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Constants

View Source
const (
	LINE_BASE   = -4
	LINE_RANGE  = 10
	PC_RANGE    = (255 - OPCODE_BASE) / LINE_RANGE
	OPCODE_BASE = 11
)

    Generate a sequence of opcodes that is as short as possible. See section 6.2.5

    View Source
    const (
    	ABase386 = (1 + iota) << 11
    	ABaseARM
    	ABaseAMD64
    	ABasePPC64
    	ABaseARM64
    	ABaseMIPS
    	ABaseRISCV
    	ABaseS390X
    	ABaseWasm
    
    	AllowedOpCodes = 1 << 11            // The number of opcodes available for any given architecture.
    	AMask          = AllowedOpCodes - 1 // AND with this to use the opcode as an array index.
    )

      Each architecture is allotted a distinct subspace of opcode values for declaring its arch-specific opcodes. Within this subspace, the first arch-specific opcode should be at offset A_ARCHSPECIFIC.

      Subspaces are aligned to a power of two so opcodes can be masked with AMask and used as compact array indices.

      View Source
      const (
      	// Don't profile the marked routine.
      	//
      	// Deprecated: Not implemented, do not use.
      	NOPROF = 1
      
      	// It is ok for the linker to get multiple of these symbols. It will
      	// pick one of the duplicates to use.
      	DUPOK = 2
      
      	// Don't insert stack check preamble.
      	NOSPLIT = 4
      
      	// Put this data in a read-only section.
      	RODATA = 8
      
      	// This data contains no pointers.
      	NOPTR = 16
      
      	// This is a wrapper function and should not count as disabling 'recover'.
      	WRAPPER = 32
      
      	// This function uses its incoming context register.
      	NEEDCTXT = 64
      
      	// When passed to ggloblsym, causes Local to be set to true on the LSym it creates.
      	LOCAL = 128
      
      	// Allocate a word of thread local storage and store the offset from the
      	// thread local base to the thread local storage in this variable.
      	TLSBSS = 256
      
      	// Do not insert instructions to allocate a stack frame for this function.
      	// Only valid on functions that declare a frame size of 0.
      	// TODO(mwhudson): only implemented for ppc64x at present.
      	NOFRAME = 512
      
      	// Function can call reflect.Type.Method or reflect.Type.MethodByName.
      	REFLECTMETHOD = 1024
      
      	// Function is the top of the call stack. Call stack unwinders should stop
      	// at this function.
      	TOPFRAME = 2048
      )
      View Source
      const (
      	C_SCOND     = (1 << 4) - 1
      	C_SBIT      = 1 << 4
      	C_PBIT      = 1 << 5
      	C_WBIT      = 1 << 6
      	C_FBIT      = 1 << 7
      	C_UBIT      = 1 << 7
      	C_SCOND_XOR = 14
      )

        ARM scond byte

        View Source
        const (
        	// Because of masking operations in the encodings, each register
        	// space should start at 0 modulo some power of 2.
        	RBase386   = 1 * 1024
        	RBaseAMD64 = 2 * 1024
        	RBaseARM   = 3 * 1024
        	RBasePPC64 = 4 * 1024  // range [4k, 8k)
        	RBaseARM64 = 8 * 1024  // range [8k, 13k)
        	RBaseMIPS  = 13 * 1024 // range [13k, 14k)
        	RBaseS390X = 14 * 1024 // range [14k, 15k)
        	RBaseRISCV = 15 * 1024 // range [15k, 16k)
        	RBaseWasm  = 16 * 1024
        )
        View Source
        const (
        	RegListARMLo = 0
        	RegListARMHi = 1 << 16
        
        	// arm64 uses the 60th bit to differentiate from other archs
        	RegListARM64Lo = 1 << 60
        	RegListARM64Hi = 1<<61 - 1
        
        	// x86 uses the 61th bit to differentiate from other archs
        	RegListX86Lo = 1 << 61
        	RegListX86Hi = 1<<62 - 1
        )

          Each architecture is allotted a distinct subspace: [Lo, Hi) for declaring its arch-specific register list numbers.

          View Source
          const (
          	LOG = 5
          )
          View Source
          const REG_NONE = 0
          View Source
          const StaticNamePref = ".stmp_"

            StaticNamePref is the prefix the front end applies to static temporary variables. When turned into LSyms, these can be tagged as static so as to avoid inserting them into the linker's name lookup tables.

            Variables

            View Source
            var Anames = []string{
            	"XXX",
            	"CALL",
            	"DUFFCOPY",
            	"DUFFZERO",
            	"END",
            	"FUNCDATA",
            	"JMP",
            	"NOP",
            	"PCALIGN",
            	"PCDATA",
            	"RET",
            	"GETCALLERPC",
            	"TEXT",
            	"UNDEF",
            }

            Functions

            func Bool2int

            func Bool2int(b bool) int

            func CConv

            func CConv(s uint8) string

              CConv formats opcode suffix bits (Prog.Scond).

              func CConvARM

              func CConvARM(s uint8) string

                CConvARM formats ARM opcode suffix bits (mostly condition codes).

                func Dconv

                func Dconv(p *Prog, a *Addr) string

                  Dconv accepts an argument 'a' within a prog 'p' and returns a string with a formatted version of the argument.

                  func DconvWithABIDetail

                  func DconvWithABIDetail(p *Prog, a *Addr) string

                    DconvDconvWithABIDetail accepts an argument 'a' within a prog 'p' and returns a string with a formatted version of the argument, in which text symbols are rendered with explicit ABI selectors.

                    func Flushplist

                    func Flushplist(ctxt *Link, plist *Plist, newprog ProgAlloc, myimportpath string)

                    func MarkUnsafePoints

                    func MarkUnsafePoints(ctxt *Link, p0 *Prog, newprog ProgAlloc, isUnsafePoint, isRestartable func(*Prog) bool)

                      MarkUnsafePoints inserts PCDATAs to mark nonpreemptible and restartable instruction sequences, based on isUnsafePoint and isRestartable predicate. p0 is the start of the instruction stream. isUnsafePoint(p) returns true if p is not safe for async preemption. isRestartable(p) returns true if we can restart at the start of p (this Prog) upon async preemption. (Currently multi-Prog restartable sequence is not supported.) isRestartable can be nil. In this case it is treated as always returning false. If isUnsafePoint(p) and isRestartable(p) are both true, it is treated as an unsafe point.

                      func Nopout

                      func Nopout(p *Prog)

                      func RLconv

                      func RLconv(list int64) string

                      func Rconv

                      func Rconv(reg int) string

                      func RegisterOpSuffix

                      func RegisterOpSuffix(arch string, cconv func(uint8) string)

                        RegisterOpSuffix assigns cconv function for formatting opcode suffixes when compiling for GOARCH=arch.

                        cconv is never called with 0 argument.

                        func RegisterOpcode

                        func RegisterOpcode(lo As, Anames []string)

                          RegisterOpcode binds a list of instruction names to a given instruction number range.

                          func RegisterRegister

                          func RegisterRegister(lo, hi int, Rconv func(int) string)

                            RegisterRegister binds a pretty-printer (Rconv) for register numbers to a given register number range. Lo is inclusive, hi exclusive (valid registers are lo through hi-1).

                            func RegisterRegisterList

                            func RegisterRegisterList(lo, hi int64, rlconv func(int64) string)

                              RegisterRegisterList binds a pretty-printer (RLconv) for register list numbers to a given register list number range. Lo is inclusive, hi exclusive (valid register list are lo through hi-1).

                              func WriteDconv

                              func WriteDconv(w io.Writer, p *Prog, a *Addr)

                                WriteDconv accepts an argument 'a' within a prog 'p' and writes a formatted version of the arg to the writer.

                                func WriteObjFile

                                func WriteObjFile(ctxt *Link, b *bio.Writer)

                                  Entry point of writing new object file.

                                  Types

                                  type ABI

                                  type ABI uint8

                                    ABI is the calling convention of a text symbol.

                                    const (
                                    	// ABI0 is the stable stack-based ABI. It's important that the
                                    	// value of this is "0": we can't distinguish between
                                    	// references to data and ABI0 text symbols in assembly code,
                                    	// and hence this doesn't distinguish between symbols without
                                    	// an ABI and text symbols with ABI0.
                                    	ABI0 ABI = iota
                                    
                                    	// ABIInternal is the internal ABI that may change between Go
                                    	// versions. All Go functions use the internal ABI and the
                                    	// compiler generates wrappers for calls to and from other
                                    	// ABIs.
                                    	ABIInternal
                                    
                                    	ABICount
                                    )

                                    func ParseABI

                                    func ParseABI(abistr string) (ABI, bool)

                                      ParseABI converts from a string representation in 'abistr' to the corresponding ABI value. Second return value is TRUE if the abi string is recognized, FALSE otherwise.

                                      func (ABI) String

                                      func (i ABI) String() string

                                      type Addr

                                      type Addr struct {
                                      	Reg    int16
                                      	Index  int16
                                      	Scale  int16 // Sometimes holds a register.
                                      	Type   AddrType
                                      	Name   AddrName
                                      	Class  int8
                                      	Offset int64
                                      	Sym    *LSym
                                      
                                      	// argument value:
                                      	//	for TYPE_SCONST, a string
                                      	//	for TYPE_FCONST, a float64
                                      	//	for TYPE_BRANCH, a *Prog (optional)
                                      	//	for TYPE_TEXTSIZE, an int32 (optional)
                                      	Val interface{}
                                      }

                                      func (*Addr) SetTarget

                                      func (a *Addr) SetTarget(t *Prog)

                                      func (*Addr) Target

                                      func (a *Addr) Target() *Prog

                                      func (*Addr) WriteNameTo

                                      func (a *Addr) WriteNameTo(w io.Writer)

                                      type AddrName

                                      type AddrName int8
                                      const (
                                      	NAME_NONE AddrName = iota
                                      	NAME_EXTERN
                                      	NAME_STATIC
                                      	NAME_AUTO
                                      	NAME_PARAM
                                      	// A reference to name@GOT(SB) is a reference to the entry in the global offset
                                      	// table for 'name'.
                                      	NAME_GOTREF
                                      	// Indicates that this is a reference to a TOC anchor.
                                      	NAME_TOCREF
                                      )

                                      type AddrPos

                                      type AddrPos struct {
                                      	Addr
                                      	Pos OperandPos
                                      }

                                        Pos indicates whether the oprand is the source or the destination.

                                        type AddrType

                                        type AddrType uint8
                                        const (
                                        	TYPE_NONE AddrType = iota
                                        	TYPE_BRANCH
                                        	TYPE_TEXTSIZE
                                        	TYPE_MEM
                                        	TYPE_CONST
                                        	TYPE_FCONST
                                        	TYPE_SCONST
                                        	TYPE_REG
                                        	TYPE_ADDR
                                        	TYPE_SHIFT
                                        	TYPE_REGREG
                                        	TYPE_REGREG2
                                        	TYPE_INDIR
                                        	TYPE_REGLIST
                                        )

                                        func (AddrType) String

                                        func (i AddrType) String() string

                                        type As

                                        type As int16

                                          An As denotes an assembler opcode. There are some portable opcodes, declared here in package obj, that are common to all architectures. However, the majority of opcodes are arch-specific and are declared in their respective architecture's subpackage.

                                          const (
                                          	AXXX As = iota
                                          	ACALL
                                          	ADUFFCOPY
                                          	ADUFFZERO
                                          	AEND
                                          	AFUNCDATA
                                          	AJMP
                                          	ANOP
                                          	APCALIGN
                                          	APCDATA
                                          	ARET
                                          	AGETCALLERPC
                                          	ATEXT
                                          	AUNDEF
                                          	A_ARCHSPECIFIC
                                          )

                                            These are the portable opcodes.

                                            func (As) String

                                            func (a As) String() string

                                            type Attribute

                                            type Attribute uint32

                                              Attribute is a set of symbol attributes.

                                              const (
                                              	AttrDuplicateOK Attribute = 1 << iota
                                              	AttrCFunc
                                              	AttrNoSplit
                                              	AttrLeaf
                                              	AttrWrapper
                                              	AttrNeedCtxt
                                              	AttrNoFrame
                                              	AttrOnList
                                              	AttrStatic
                                              
                                              	// MakeTypelink means that the type should have an entry in the typelink table.
                                              	AttrMakeTypelink
                                              
                                              	// ReflectMethod means the function may call reflect.Type.Method or
                                              	// reflect.Type.MethodByName. Matching is imprecise (as reflect.Type
                                              	// can be used through a custom interface), so ReflectMethod may be
                                              	// set in some cases when the reflect package is not called.
                                              	//
                                              	// Used by the linker to determine what methods can be pruned.
                                              	AttrReflectMethod
                                              
                                              	// Local means make the symbol local even when compiling Go code to reference Go
                                              	// symbols in other shared libraries, as in this mode symbols are global by
                                              	// default. "local" here means in the sense of the dynamic linker, i.e. not
                                              	// visible outside of the module (shared library or executable) that contains its
                                              	// definition. (When not compiling to support Go shared libraries, all symbols are
                                              	// local in this sense unless there is a cgo_export_* directive).
                                              	AttrLocal
                                              
                                              	// For function symbols; indicates that the specified function was the
                                              	// target of an inline during compilation
                                              	AttrWasInlined
                                              
                                              	// TopFrame means that this function is an entry point and unwinders should not
                                              	// keep unwinding beyond this frame.
                                              	AttrTopFrame
                                              
                                              	// Indexed indicates this symbol has been assigned with an index (when using the
                                              	// new object file format).
                                              	AttrIndexed
                                              
                                              	// Only applied on type descriptor symbols, UsedInIface indicates this type is
                                              	// converted to an interface.
                                              	//
                                              	// Used by the linker to determine what methods can be pruned.
                                              	AttrUsedInIface
                                              
                                              	// ContentAddressable indicates this is a content-addressable symbol.
                                              	AttrContentAddressable
                                              )

                                              func (Attribute) ABI

                                              func (a Attribute) ABI() ABI

                                              func (Attribute) CFunc

                                              func (a Attribute) CFunc() bool

                                              func (Attribute) ContentAddressable

                                              func (a Attribute) ContentAddressable() bool

                                              func (Attribute) DuplicateOK

                                              func (a Attribute) DuplicateOK() bool

                                              func (Attribute) Indexed

                                              func (a Attribute) Indexed() bool

                                              func (Attribute) Leaf

                                              func (a Attribute) Leaf() bool

                                              func (Attribute) Local

                                              func (a Attribute) Local() bool
                                              func (a Attribute) MakeTypelink() bool

                                              func (Attribute) NeedCtxt

                                              func (a Attribute) NeedCtxt() bool

                                              func (Attribute) NoFrame

                                              func (a Attribute) NoFrame() bool

                                              func (Attribute) NoSplit

                                              func (a Attribute) NoSplit() bool

                                              func (Attribute) OnList

                                              func (a Attribute) OnList() bool

                                              func (Attribute) ReflectMethod

                                              func (a Attribute) ReflectMethod() bool

                                              func (*Attribute) Set

                                              func (a *Attribute) Set(flag Attribute, value bool)

                                              func (*Attribute) SetABI

                                              func (a *Attribute) SetABI(abi ABI)

                                              func (Attribute) Static

                                              func (a Attribute) Static() bool

                                              func (Attribute) TextAttrString

                                              func (a Attribute) TextAttrString() string

                                                TextAttrString formats a for printing in as part of a TEXT prog.

                                                func (Attribute) TopFrame

                                                func (a Attribute) TopFrame() bool

                                                func (Attribute) UsedInIface

                                                func (a Attribute) UsedInIface() bool

                                                func (Attribute) WasInlined

                                                func (a Attribute) WasInlined() bool

                                                func (Attribute) Wrapper

                                                func (a Attribute) Wrapper() bool

                                                type Auto

                                                type Auto struct {
                                                	Asym    *LSym
                                                	Aoffset int32
                                                	Name    AddrName
                                                	Gotype  *LSym
                                                }

                                                type BySymName

                                                type BySymName []*LSym

                                                func (BySymName) Len

                                                func (s BySymName) Len() int

                                                func (BySymName) Less

                                                func (s BySymName) Less(i, j int) bool

                                                func (BySymName) Swap

                                                func (s BySymName) Swap(i, j int)

                                                type DwarfFixupTable

                                                type DwarfFixupTable struct {
                                                	// contains filtered or unexported fields
                                                }

                                                  This table is designed to aid in the creation of references between DWARF subprogram DIEs.

                                                  In most cases when one DWARF DIE has to refer to another DWARF DIE, the target of the reference has an LSym, which makes it easy to use the existing relocation mechanism. For DWARF inlined routine DIEs, however, the subprogram DIE has to refer to a child parameter/variable DIE of the abstract subprogram. This child DIE doesn't have an LSym, and also of interest is the fact that when DWARF generation is happening for inlined function F within caller G, it's possible that DWARF generation hasn't happened yet for F, so there is no way to know the offset of a child DIE within F's abstract function. Making matters more complex, each inlined instance of F may refer to a subset of the original F's variables (depending on what happens with optimization, some vars may be eliminated).

                                                  The fixup table below helps overcome this hurdle. At the point where a parameter/variable reference is made (via a call to "ReferenceChildDIE"), a fixup record is generate that records the relocation that is targeting that child variable. At a later point when the abstract function DIE is emitted, there will be a call to "RegisterChildDIEOffsets", at which point the offsets needed to apply fixups are captured. Finally, once the parallel portion of the compilation is done, fixups can actually be applied during the "Finalize" method (this can't be done during the parallel portion of the compile due to the possibility of data races).

                                                  This table is also used to record the "precursor" function node for each function that is the target of an inline -- child DIE references have to be made with respect to the original pre-optimization version of the function (to allow for the fact that each inlined body may be optimized differently).

                                                  func NewDwarfFixupTable

                                                  func NewDwarfFixupTable(ctxt *Link) *DwarfFixupTable

                                                  func (*DwarfFixupTable) AbsFuncDwarfSym

                                                  func (ft *DwarfFixupTable) AbsFuncDwarfSym(fnsym *LSym) *LSym

                                                    return the LSym corresponding to the 'abstract subprogram' DWARF info entry for a function.

                                                    func (*DwarfFixupTable) Finalize

                                                    func (ft *DwarfFixupTable) Finalize(myimportpath string, trace bool)

                                                      Called after all functions have been compiled; the main job of this function is to identify cases where there are outstanding fixups. This scenario crops up when we have references to variables of an inlined routine, but that routine is defined in some other package. This helper walks through and locate these fixups, then invokes a helper to create an abstract subprogram DIE for each one.

                                                      func (*DwarfFixupTable) GetPrecursorFunc

                                                      func (ft *DwarfFixupTable) GetPrecursorFunc(s *LSym) interface{}

                                                      func (*DwarfFixupTable) ReferenceChildDIE

                                                      func (ft *DwarfFixupTable) ReferenceChildDIE(s *LSym, ridx int, tgt *LSym, dclidx int, inlIndex int)

                                                        Make a note of a child DIE reference: relocation 'ridx' within symbol 's' is targeting child 'c' of DIE with symbol 'tgt'.

                                                        func (*DwarfFixupTable) RegisterChildDIEOffsets

                                                        func (ft *DwarfFixupTable) RegisterChildDIEOffsets(s *LSym, vars []*dwarf.Var, coffsets []int32)

                                                          Called once DWARF generation is complete for a given abstract function, whose children might have been referenced via a call above. Stores the offsets for any child DIEs (vars, params) so that they can be consumed later in on DwarfFixupTable.Finalize, which applies any outstanding fixups.

                                                          func (*DwarfFixupTable) SetPrecursorFunc

                                                          func (ft *DwarfFixupTable) SetPrecursorFunc(s *LSym, fn interface{})

                                                          type FileInfo

                                                          type FileInfo struct {
                                                          	Name string // name of file to read into object file
                                                          	Size int64  // length of file
                                                          }

                                                            A FileInfo contains extra fields for SDATA symbols backed by files. (If LSym.Extra is a *FileInfo, LSym.P == nil.)

                                                            type FuncInfo

                                                            type FuncInfo struct {
                                                            	Args     int32
                                                            	Locals   int32
                                                            	Align    int32
                                                            	FuncID   objabi.FuncID
                                                            	Text     *Prog
                                                            	Autot    map[*LSym]struct{}
                                                            	Pcln     Pcln
                                                            	InlMarks []InlMark
                                                            
                                                            	GCArgs             *LSym
                                                            	GCLocals           *LSym
                                                            	StackObjects       *LSym
                                                            	OpenCodedDeferInfo *LSym
                                                            
                                                            	FuncInfoSym *LSym
                                                            	// contains filtered or unexported fields
                                                            }

                                                              A FuncInfo contains extra fields for STEXT symbols.

                                                              func (*FuncInfo) AddInlMark

                                                              func (fi *FuncInfo) AddInlMark(p *Prog, id int32)

                                                                Mark p as the instruction to set as the pc when "unwinding" the inlining global frame id. Usually it should be instruction with a file:line at the callsite, and occur just before the body of the inlined function.

                                                                func (*FuncInfo) RecordAutoType

                                                                func (fi *FuncInfo) RecordAutoType(gotype *LSym)

                                                                  Record the type symbol for an auto variable so that the linker an emit DWARF type information for the type.

                                                                  type InlMark

                                                                  type InlMark struct {
                                                                  	// contains filtered or unexported fields
                                                                  }

                                                                  type InlTree

                                                                  type InlTree struct {
                                                                  	// contains filtered or unexported fields
                                                                  }

                                                                    InlTree is a collection of inlined calls. The Parent field of an InlinedCall is the index of another InlinedCall in InlTree.

                                                                    The compiler maintains a global inlining tree and adds a node to it every time a function is inlined. For example, suppose f() calls g() and g has two calls to h(), and that f, g, and h are inlineable:

                                                                    1 func main() {
                                                                    2     f()
                                                                    3 }
                                                                    4 func f() {
                                                                    5     g()
                                                                    6 }
                                                                    7 func g() {
                                                                    8     h()
                                                                    9     h()
                                                                    

                                                                    10 } 11 func h() { 12 println("H") 13 }

                                                                    Assuming the global tree starts empty, inlining will produce the following tree:

                                                                    []InlinedCall{
                                                                      {Parent: -1, Func: "f", Pos: <line 2>},
                                                                      {Parent:  0, Func: "g", Pos: <line 5>},
                                                                      {Parent:  1, Func: "h", Pos: <line 8>},
                                                                      {Parent:  1, Func: "h", Pos: <line 9>},
                                                                    }
                                                                    

                                                                    The nodes of h inlined into main will have inlining indexes 2 and 3.

                                                                    Eventually, the compiler extracts a per-function inlining tree from the global inlining tree (see pcln.go).

                                                                    func (*InlTree) Add

                                                                    func (tree *InlTree) Add(parent int, pos src.XPos, func_ *LSym) int

                                                                      Add adds a new call to the tree, returning its index.

                                                                      func (*InlTree) CallPos

                                                                      func (tree *InlTree) CallPos(inlIndex int) src.XPos

                                                                      func (*InlTree) InlinedFunction

                                                                      func (tree *InlTree) InlinedFunction(inlIndex int) *LSym

                                                                      func (*InlTree) Parent

                                                                      func (tree *InlTree) Parent(inlIndex int) int

                                                                      type InlinedCall

                                                                      type InlinedCall struct {
                                                                      	Parent   int      // index of the parent in the InlTree or < 0 if outermost call
                                                                      	Pos      src.XPos // position of the inlined call
                                                                      	Func     *LSym    // function that was inlined
                                                                      	ParentPC int32    // PC of instruction just before inlined body. Only valid in local trees.
                                                                      }

                                                                        InlinedCall is a node in an InlTree.

                                                                        type LSym

                                                                        type LSym struct {
                                                                        	Name string
                                                                        	Type objabi.SymKind
                                                                        	Attribute
                                                                        
                                                                        	Size   int64
                                                                        	Gotype *LSym
                                                                        	P      []byte
                                                                        	R      []Reloc
                                                                        
                                                                        	Extra *interface{} // *FuncInfo or *FileInfo, if present
                                                                        
                                                                        	Pkg    string
                                                                        	PkgIdx int32
                                                                        	SymIdx int32
                                                                        }

                                                                          An LSym is the sort of symbol that is written to an object file. It represents Go symbols in a flat pkg+"."+name namespace.

                                                                          func (*LSym) CanBeAnSSASym

                                                                          func (s *LSym) CanBeAnSSASym()

                                                                            The compiler needs *LSym to be assignable to cmd/compile/internal/ssa.Sym.

                                                                            func (*LSym) File

                                                                            func (s *LSym) File() *FileInfo

                                                                              File returns the *FileInfo associated with s, or else nil.

                                                                              func (*LSym) Func

                                                                              func (s *LSym) Func() *FuncInfo

                                                                                Func returns the *FuncInfo associated with s, or else nil.

                                                                                func (*LSym) Grow

                                                                                func (s *LSym) Grow(lsiz int64)

                                                                                  Grow increases the length of s.P to lsiz.

                                                                                  func (*LSym) GrowCap

                                                                                  func (s *LSym) GrowCap(c int64)

                                                                                    GrowCap increases the capacity of s.P to c.

                                                                                    func (*LSym) Length

                                                                                    func (s *LSym) Length(dwarfContext interface{}) int64

                                                                                    func (*LSym) NewFileInfo

                                                                                    func (s *LSym) NewFileInfo() *FileInfo

                                                                                      NewFileInfo allocates and returns a FileInfo for LSym.

                                                                                      func (*LSym) NewFuncInfo

                                                                                      func (s *LSym) NewFuncInfo() *FuncInfo

                                                                                        NewFuncInfo allocates and returns a FuncInfo for LSym.

                                                                                        func (*LSym) String

                                                                                        func (s *LSym) String() string

                                                                                        func (*LSym) WriteAddr

                                                                                        func (s *LSym) WriteAddr(ctxt *Link, off int64, siz int, rsym *LSym, roff int64)

                                                                                          WriteAddr writes an address of size siz into s at offset off. rsym and roff specify the relocation for the address.

                                                                                          func (*LSym) WriteBytes

                                                                                          func (s *LSym) WriteBytes(ctxt *Link, off int64, b []byte) int64

                                                                                            WriteBytes writes a slice of bytes into s at offset off.

                                                                                            func (*LSym) WriteCURelativeAddr

                                                                                            func (s *LSym) WriteCURelativeAddr(ctxt *Link, off int64, rsym *LSym, roff int64)

                                                                                              WriteCURelativeAddr writes a pointer-sized address into s at offset off. rsym and roff specify the relocation for the address which will be resolved by the linker to an offset from the DW_AT_low_pc attribute of the DWARF Compile Unit of rsym.

                                                                                              func (*LSym) WriteFloat32

                                                                                              func (s *LSym) WriteFloat32(ctxt *Link, off int64, f float32)

                                                                                                WriteFloat32 writes f into s at offset off.

                                                                                                func (*LSym) WriteFloat64

                                                                                                func (s *LSym) WriteFloat64(ctxt *Link, off int64, f float64)

                                                                                                  WriteFloat64 writes f into s at offset off.

                                                                                                  func (*LSym) WriteInt

                                                                                                  func (s *LSym) WriteInt(ctxt *Link, off int64, siz int, i int64)

                                                                                                    WriteInt writes an integer i of size siz into s at offset off.

                                                                                                    func (*LSym) WriteOff

                                                                                                    func (s *LSym) WriteOff(ctxt *Link, off int64, rsym *LSym, roff int64)

                                                                                                      WriteOff writes a 4 byte offset to rsym+roff into s at offset off. After linking the 4 bytes stored at s+off will be rsym+roff-(start of section that s is in).

                                                                                                      func (*LSym) WriteString

                                                                                                      func (s *LSym) WriteString(ctxt *Link, off int64, siz int, str string)

                                                                                                        WriteString writes a string of size siz into s at offset off.

                                                                                                        func (*LSym) WriteWeakOff

                                                                                                        func (s *LSym) WriteWeakOff(ctxt *Link, off int64, rsym *LSym, roff int64)

                                                                                                          WriteWeakOff writes a weak 4 byte offset to rsym+roff into s at offset off. After linking the 4 bytes stored at s+off will be rsym+roff-(start of section that s is in).

                                                                                                          type Link struct {
                                                                                                          	Headtype           objabi.HeadType
                                                                                                          	Arch               *LinkArch
                                                                                                          	Debugasm           int
                                                                                                          	Debugvlog          bool
                                                                                                          	Debugpcln          string
                                                                                                          	Flag_shared        bool
                                                                                                          	Flag_dynlink       bool
                                                                                                          	Flag_linkshared    bool
                                                                                                          	Flag_optimize      bool
                                                                                                          	Flag_locationlists bool
                                                                                                          	Retpoline          bool // emit use of retpoline stubs for indirect jmp/call
                                                                                                          	Bso                *bufio.Writer
                                                                                                          	Pathname           string
                                                                                                          	Pkgpath            string // the current package's import path, "" if unknown
                                                                                                          
                                                                                                          	PosTable        src.PosTable
                                                                                                          	InlTree         InlTree // global inlining tree used by gc/inl.go
                                                                                                          	DwFixups        *DwarfFixupTable
                                                                                                          	Imports         []goobj.ImportedPkg
                                                                                                          	DiagFunc        func(string, ...interface{})
                                                                                                          	DiagFlush       func()
                                                                                                          	DebugInfo       func(fn *LSym, info *LSym, curfn interface{}) ([]dwarf.Scope, dwarf.InlCalls) // if non-nil, curfn is a *gc.Node
                                                                                                          	GenAbstractFunc func(fn *LSym)
                                                                                                          	Errors          int
                                                                                                          
                                                                                                          	InParallel    bool // parallel backend phase in effect
                                                                                                          	UseBASEntries bool // use Base Address Selection Entries in location lists and PC ranges
                                                                                                          	IsAsm         bool // is the source assembly language, which may contain surprising idioms (e.g., call tables)
                                                                                                          
                                                                                                          	// state for writing objects
                                                                                                          	Text []*LSym
                                                                                                          	Data []*LSym
                                                                                                          
                                                                                                          	// ABIAliases are text symbols that should be aliased to all
                                                                                                          	// ABIs. These symbols may only be referenced and not defined
                                                                                                          	// by this object, since the need for an alias may appear in a
                                                                                                          	// different object than the definition. Hence, this
                                                                                                          	// information can't be carried in the symbol definition.
                                                                                                          	//
                                                                                                          	// TODO(austin): Replace this with ABI wrappers once the ABIs
                                                                                                          	// actually diverge.
                                                                                                          	ABIAliases []*LSym
                                                                                                          
                                                                                                          	Fingerprint goobj.FingerprintType // fingerprint of symbol indices, to catch index mismatch
                                                                                                          	// contains filtered or unexported fields
                                                                                                          }

                                                                                                            Link holds the context for writing object code from a compiler to be linker input or for reading that input into the linker.

                                                                                                            func Linknew

                                                                                                            func Linknew(arch *LinkArch) *Link

                                                                                                            func (*Link) AddImport

                                                                                                            func (ctxt *Link) AddImport(pkg string, fingerprint goobj.FingerprintType)

                                                                                                              AddImport adds a package to the list of imported packages.

                                                                                                              func (*Link) AllPos

                                                                                                              func (ctxt *Link) AllPos(xpos src.XPos, result []src.Pos) []src.Pos

                                                                                                                AllPos returns a slice of the positions inlined at xpos, from innermost (index zero) to outermost. To avoid gratuitous allocation the result is passed in and extended if necessary.

                                                                                                                func (*Link) CanReuseProgs

                                                                                                                func (ctxt *Link) CanReuseProgs() bool

                                                                                                                func (*Link) Diag

                                                                                                                func (ctxt *Link) Diag(format string, args ...interface{})

                                                                                                                func (*Link) DwarfAbstractFunc

                                                                                                                func (ctxt *Link) DwarfAbstractFunc(curfn interface{}, s *LSym, myimportpath string)

                                                                                                                func (*Link) DwarfIntConst

                                                                                                                func (ctxt *Link) DwarfIntConst(myimportpath, name, typename string, val int64)

                                                                                                                  DwarfIntConst creates a link symbol for an integer constant with the given name, type and value.

                                                                                                                  func (*Link) EmitEntryLiveness

                                                                                                                  func (ctxt *Link) EmitEntryLiveness(s *LSym, p *Prog, newprog ProgAlloc) *Prog

                                                                                                                    EmitEntryLiveness generates PCDATA Progs after p to switch to the liveness map active at the entry of function s. It returns the last Prog generated.

                                                                                                                    func (*Link) EmitEntryStackMap

                                                                                                                    func (ctxt *Link) EmitEntryStackMap(s *LSym, p *Prog, newprog ProgAlloc) *Prog

                                                                                                                      Similar to EmitEntryLiveness, but just emit stack map.

                                                                                                                      func (*Link) EmitEntryUnsafePoint

                                                                                                                      func (ctxt *Link) EmitEntryUnsafePoint(s *LSym, p *Prog, newprog ProgAlloc) *Prog

                                                                                                                        Similar to EmitEntryLiveness, but just emit unsafe point map.

                                                                                                                        func (*Link) EndUnsafePoint

                                                                                                                        func (ctxt *Link) EndUnsafePoint(p *Prog, newprog ProgAlloc, oldval int64) *Prog

                                                                                                                          EndUnsafePoint generates PCDATA Progs after p to mark the end of an unsafe point, restoring the register map index to oldval. The unsafe point ends right after p. It returns the last Prog generated.

                                                                                                                          func (*Link) FixedFrameSize

                                                                                                                          func (ctxt *Link) FixedFrameSize() int64

                                                                                                                            The smallest possible offset from the hardware stack pointer to a local variable on the stack. Architectures that use a link register save its value on the stack in the function prologue and so always have a pointer between the hardware stack pointer and the local variable area.

                                                                                                                            func (*Link) Float32Sym

                                                                                                                            func (ctxt *Link) Float32Sym(f float32) *LSym

                                                                                                                            func (*Link) Float64Sym

                                                                                                                            func (ctxt *Link) Float64Sym(f float64) *LSym

                                                                                                                            func (*Link) Globl

                                                                                                                            func (ctxt *Link) Globl(s *LSym, size int64, flag int)

                                                                                                                            func (*Link) InitTextSym

                                                                                                                            func (ctxt *Link) InitTextSym(s *LSym, flag int)

                                                                                                                            func (*Link) InnermostPos

                                                                                                                            func (ctxt *Link) InnermostPos(xpos src.XPos) src.Pos

                                                                                                                              InnermostPos returns the innermost position corresponding to xpos, that is, the code that is inlined and that inlines nothing else. In the example for InlTree above, the code for println within h would have an innermost position with line number 12, whether h was not inlined, inlined into g, g-then-f, or g-then-f-then-main. This corresponds to what someone debugging main, f, g, or h might expect to see while single-stepping.

                                                                                                                              func (*Link) Int64Sym

                                                                                                                              func (ctxt *Link) Int64Sym(i int64) *LSym

                                                                                                                              func (*Link) Logf

                                                                                                                              func (ctxt *Link) Logf(format string, args ...interface{})

                                                                                                                              func (*Link) Lookup

                                                                                                                              func (ctxt *Link) Lookup(name string) *LSym

                                                                                                                                Lookup looks up the symbol with name name. If it does not exist, it creates it.

                                                                                                                                func (*Link) LookupABI

                                                                                                                                func (ctxt *Link) LookupABI(name string, abi ABI) *LSym

                                                                                                                                  LookupABI looks up a symbol with the given ABI. If it does not exist, it creates it.

                                                                                                                                  func (*Link) LookupABIInit

                                                                                                                                  func (ctxt *Link) LookupABIInit(name string, abi ABI, init func(s *LSym)) *LSym

                                                                                                                                    LookupABI looks up a symbol with the given ABI. If it does not exist, it creates it and passes it to init for one-time initialization.

                                                                                                                                    func (*Link) LookupDerived

                                                                                                                                    func (ctxt *Link) LookupDerived(s *LSym, name string) *LSym

                                                                                                                                      LookupDerived looks up or creates the symbol with name name derived from symbol s. The resulting symbol will be static iff s is.

                                                                                                                                      func (*Link) LookupInit

                                                                                                                                      func (ctxt *Link) LookupInit(name string, init func(s *LSym)) *LSym

                                                                                                                                        LookupInit looks up the symbol with name name. If it does not exist, it creates it and passes it to init for one-time initialization.

                                                                                                                                        func (*Link) LookupStatic

                                                                                                                                        func (ctxt *Link) LookupStatic(name string) *LSym

                                                                                                                                          LookupStatic looks up the static symbol with name name. If it does not exist, it creates it.

                                                                                                                                          func (*Link) NewProg

                                                                                                                                          func (ctxt *Link) NewProg() *Prog

                                                                                                                                          func (*Link) NumberSyms

                                                                                                                                          func (ctxt *Link) NumberSyms()

                                                                                                                                            Assign index to symbols. asm is set to true if this is called by the assembler (i.e. not the compiler), in which case all the symbols are non-package (for now).

                                                                                                                                            func (*Link) OutermostPos

                                                                                                                                            func (ctxt *Link) OutermostPos(xpos src.XPos) src.Pos

                                                                                                                                              OutermostPos returns the outermost position corresponding to xpos, which is where xpos was ultimately inlined to. In the example for InlTree, main() contains inlined AST nodes from h(), but the outermost position for those nodes is line 2.

                                                                                                                                              func (*Link) StartUnsafePoint

                                                                                                                                              func (ctxt *Link) StartUnsafePoint(p *Prog, newprog ProgAlloc) *Prog

                                                                                                                                                StartUnsafePoint generates PCDATA Progs after p to mark the beginning of an unsafe point. The unsafe point starts immediately after p. It returns the last Prog generated.

                                                                                                                                                type LinkArch

                                                                                                                                                type LinkArch struct {
                                                                                                                                                	*sys.Arch
                                                                                                                                                	Init           func(*Link)
                                                                                                                                                	Preprocess     func(*Link, *LSym, ProgAlloc)
                                                                                                                                                	Assemble       func(*Link, *LSym, ProgAlloc)
                                                                                                                                                	Progedit       func(*Link, *Prog, ProgAlloc)
                                                                                                                                                	UnaryDst       map[As]bool // Instruction takes one operand, a destination.
                                                                                                                                                	DWARFRegisters map[int16]int16
                                                                                                                                                }

                                                                                                                                                  LinkArch is the definition of a single architecture.

                                                                                                                                                  type OperandPos

                                                                                                                                                  type OperandPos int8
                                                                                                                                                  const (
                                                                                                                                                  	Source OperandPos = iota
                                                                                                                                                  	Destination
                                                                                                                                                  )

                                                                                                                                                  type PCIter

                                                                                                                                                  type PCIter struct {
                                                                                                                                                  	PC      uint32
                                                                                                                                                  	NextPC  uint32
                                                                                                                                                  	PCScale uint32
                                                                                                                                                  	Value   int32
                                                                                                                                                  
                                                                                                                                                  	Done bool
                                                                                                                                                  	// contains filtered or unexported fields
                                                                                                                                                  }

                                                                                                                                                    PCIter iterates over encoded pcdata tables.

                                                                                                                                                    func NewPCIter

                                                                                                                                                    func NewPCIter(pcScale uint32) *PCIter

                                                                                                                                                      newPCIter creates a PCIter with a scale factor for the PC step size.

                                                                                                                                                      func (*PCIter) Init

                                                                                                                                                      func (it *PCIter) Init(p []byte)

                                                                                                                                                        init prepares it to iterate over p, and advances it to the first pc.

                                                                                                                                                        func (*PCIter) Next

                                                                                                                                                        func (it *PCIter) Next()

                                                                                                                                                          Next advances it to the Next pc.

                                                                                                                                                          type Pcln

                                                                                                                                                          type Pcln struct {
                                                                                                                                                          	// Aux symbols for pcln
                                                                                                                                                          	Pcsp        *LSym
                                                                                                                                                          	Pcfile      *LSym
                                                                                                                                                          	Pcline      *LSym
                                                                                                                                                          	Pcinline    *LSym
                                                                                                                                                          	Pcdata      []*LSym
                                                                                                                                                          	Funcdata    []*LSym
                                                                                                                                                          	Funcdataoff []int64
                                                                                                                                                          	UsedFiles   map[goobj.CUFileIndex]struct{} // file indices used while generating pcfile
                                                                                                                                                          	InlTree     InlTree                        // per-function inlining tree extracted from the global tree
                                                                                                                                                          }

                                                                                                                                                          type Plist

                                                                                                                                                          type Plist struct {
                                                                                                                                                          	Firstpc *Prog
                                                                                                                                                          	Curfn   interface{} // holds a *gc.Node, if non-nil
                                                                                                                                                          }

                                                                                                                                                          type Prog

                                                                                                                                                          type Prog struct {
                                                                                                                                                          	Ctxt     *Link     // linker context
                                                                                                                                                          	Link     *Prog     // next Prog in linked list
                                                                                                                                                          	From     Addr      // first source operand
                                                                                                                                                          	RestArgs []AddrPos // can pack any operands that not fit into {Prog.From, Prog.To}
                                                                                                                                                          	To       Addr      // destination operand (second is RegTo2 below)
                                                                                                                                                          	Pool     *Prog     // constant pool entry, for arm,arm64 back ends
                                                                                                                                                          	Forwd    *Prog     // for x86 back end
                                                                                                                                                          	Rel      *Prog     // for x86, arm back ends
                                                                                                                                                          	Pc       int64     // for back ends or assembler: virtual or actual program counter, depending on phase
                                                                                                                                                          	Pos      src.XPos  // source position of this instruction
                                                                                                                                                          	Spadj    int32     // effect of instruction on stack pointer (increment or decrement amount)
                                                                                                                                                          	As       As        // assembler opcode
                                                                                                                                                          	Reg      int16     // 2nd source operand
                                                                                                                                                          	RegTo2   int16     // 2nd destination operand
                                                                                                                                                          	Mark     uint16    // bitmask of arch-specific items
                                                                                                                                                          	Optab    uint16    // arch-specific opcode index
                                                                                                                                                          	Scond    uint8     // bits that describe instruction suffixes (e.g. ARM conditions)
                                                                                                                                                          	Back     uint8     // for x86 back end: backwards branch state
                                                                                                                                                          	Ft       uint8     // for x86 back end: type index of Prog.From
                                                                                                                                                          	Tt       uint8     // for x86 back end: type index of Prog.To
                                                                                                                                                          	Isize    uint8     // for x86 back end: size of the instruction in bytes
                                                                                                                                                          }

                                                                                                                                                            Prog describes a single machine instruction.

                                                                                                                                                            The general instruction form is:

                                                                                                                                                            (1) As.Scond From [, ...RestArgs], To
                                                                                                                                                            (2) As.Scond From, Reg [, ...RestArgs], To, RegTo2
                                                                                                                                                            

                                                                                                                                                            where As is an opcode and the others are arguments: From, Reg are sources, and To, RegTo2 are destinations. RestArgs can hold additional sources and destinations. Usually, not all arguments are present. For example, MOVL R1, R2 encodes using only As=MOVL, From=R1, To=R2. The Scond field holds additional condition bits for systems (like arm) that have generalized conditional execution. (2) form is present for compatibility with older code, to avoid too much changes in a single swing. (1) scheme is enough to express any kind of operand combination.

                                                                                                                                                            Jump instructions use the To.Val field to point to the target *Prog, which must be in the same linked list as the jump instruction.

                                                                                                                                                            The Progs for a given function are arranged in a list linked through the Link field.

                                                                                                                                                            Each Prog is charged to a specific source line in the debug information, specified by Pos.Line(). Every Prog has a Ctxt field that defines its context. For performance reasons, Progs usually are usually bulk allocated, cached, and reused; those bulk allocators should always be used, rather than new(Prog).

                                                                                                                                                            The other fields not yet mentioned are for use by the back ends and should be left zeroed by creators of Prog lists.

                                                                                                                                                            func Appendp

                                                                                                                                                            func Appendp(q *Prog, newprog ProgAlloc) *Prog

                                                                                                                                                            func (*Prog) From3Type

                                                                                                                                                            func (p *Prog) From3Type() AddrType

                                                                                                                                                              From3Type returns p.GetFrom3().Type, or TYPE_NONE when p.GetFrom3() returns nil.

                                                                                                                                                              Deprecated: for the same reasons as Prog.GetFrom3.

                                                                                                                                                              func (*Prog) GetFrom3

                                                                                                                                                              func (p *Prog) GetFrom3() *Addr

                                                                                                                                                                GetFrom3 returns second source operand (the first is Prog.From). In combination with Prog.From and Prog.To it makes common 3 operand case easier to use.

                                                                                                                                                                Should be used only when RestArgs is set with SetFrom3.

                                                                                                                                                                Deprecated: better use RestArgs directly or define backend-specific getters. Introduced to simplify transition to []Addr. Usage of this is discouraged due to fragility and lack of guarantees.

                                                                                                                                                                func (*Prog) GetTo2

                                                                                                                                                                func (p *Prog) GetTo2() *Addr

                                                                                                                                                                  GetTo2 returns the second destination operand.

                                                                                                                                                                  func (*Prog) InnermostFilename

                                                                                                                                                                  func (p *Prog) InnermostFilename() string

                                                                                                                                                                    InnermostFilename returns a string containing the innermost (in inlining) filename at p's position

                                                                                                                                                                    func (*Prog) InnermostLine

                                                                                                                                                                    func (p *Prog) InnermostLine(w io.Writer)

                                                                                                                                                                    func (*Prog) InnermostLineNumber

                                                                                                                                                                    func (p *Prog) InnermostLineNumber() string

                                                                                                                                                                      InnermostLineNumber returns a string containing the line number for the innermost inlined function (if any inlining) at p's position

                                                                                                                                                                      func (*Prog) InnermostLineNumberHTML

                                                                                                                                                                      func (p *Prog) InnermostLineNumberHTML() string

                                                                                                                                                                        InnermostLineNumberHTML returns a string containing the line number for the innermost inlined function (if any inlining) at p's position

                                                                                                                                                                        func (*Prog) InnermostString

                                                                                                                                                                        func (p *Prog) InnermostString(w io.Writer)

                                                                                                                                                                        func (*Prog) InstructionString

                                                                                                                                                                        func (p *Prog) InstructionString() string

                                                                                                                                                                          InstructionString returns a string representation of the instruction without preceding program counter or file and line number.

                                                                                                                                                                          func (*Prog) Line

                                                                                                                                                                          func (p *Prog) Line() string

                                                                                                                                                                            Line returns a string containing the filename and line number for p

                                                                                                                                                                            func (*Prog) SetFrom3

                                                                                                                                                                            func (p *Prog) SetFrom3(a Addr)

                                                                                                                                                                              SetFrom3 assigns []Args{{a, 0}} to p.RestArgs. In pair with Prog.GetFrom3 it can help in emulation of Prog.From3.

                                                                                                                                                                              Deprecated: for the same reasons as Prog.GetFrom3.

                                                                                                                                                                              func (*Prog) SetRestArgs

                                                                                                                                                                              func (p *Prog) SetRestArgs(args []Addr)

                                                                                                                                                                                SetRestArgs assigns more than one source operands to p.RestArgs.

                                                                                                                                                                                func (*Prog) SetTo2

                                                                                                                                                                                func (p *Prog) SetTo2(a Addr)

                                                                                                                                                                                  SetTo2 assings []Args{{a, 1}} to p.RestArgs when the second destination operand does not fit into prog.RegTo2.

                                                                                                                                                                                  func (*Prog) String

                                                                                                                                                                                  func (p *Prog) String() string

                                                                                                                                                                                  func (*Prog) WriteInstructionString

                                                                                                                                                                                  func (p *Prog) WriteInstructionString(w io.Writer)

                                                                                                                                                                                    WriteInstructionString writes a string representation of the instruction without preceding program counter or file and line number.

                                                                                                                                                                                    type ProgAlloc

                                                                                                                                                                                    type ProgAlloc func() *Prog

                                                                                                                                                                                      ProgAlloc is a function that allocates Progs. It is used to provide access to cached/bulk-allocated Progs to the assemblers.

                                                                                                                                                                                      type Reloc

                                                                                                                                                                                      type Reloc struct {
                                                                                                                                                                                      	Off  int32
                                                                                                                                                                                      	Siz  uint8
                                                                                                                                                                                      	Type objabi.RelocType
                                                                                                                                                                                      	Add  int64
                                                                                                                                                                                      	Sym  *LSym
                                                                                                                                                                                      }

                                                                                                                                                                                      func Addrel

                                                                                                                                                                                      func Addrel(s *LSym) *Reloc

                                                                                                                                                                                      Directories

                                                                                                                                                                                      Path Synopsis
                                                                                                                                                                                      Package arm64 implements an ARM64 assembler.
                                                                                                                                                                                      Package arm64 implements an ARM64 assembler.
                                                                                                                                                                                      Package ppc64 implements a PPC64 assembler that assembles Go asm into the corresponding PPC64 instructions as defined by the Power ISA 3.0B. This document provides information on how to write code in Go assembler for PPC64, focusing on the differences between Go and PPC64 assembly language.
                                                                                                                                                                                      Package ppc64 implements a PPC64 assembler that assembles Go asm into the corresponding PPC64 instructions as defined by the Power ISA 3.0B. This document provides information on how to write code in Go assembler for PPC64, focusing on the differences between Go and PPC64 assembly language.