obj

package standard library
go1.16beta1 Latest Latest
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 Go to latest Published: Dec 17, 2020 License: BSD-3-Clause Imports: 20 Imported by: 0

Documentation

Index

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 added in go1.11 

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 added in go1.16 

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 added in go1.6 

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

func MarkUnsafePoints added in go1.14 

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 added in go1.10 

func RLconv(list int64) string

func Rconv 

func Rconv(reg int) string

func RegisterOpSuffix added in go1.11 

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 added in go1.10 

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 added in go1.15 

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 added in go1.7 

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

Entry point of writing new object file.

Types

type ABI added in go1.12 

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 added in go1.16 

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 added in go1.12 

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 added in go1.16 

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

func (*Addr) Target added in go1.16 

func (a *Addr) Target() *Prog

func (*Addr) WriteNameTo added in go1.15 

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

type AddrName added in go1.9 

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 added in go1.16 

type AddrPos struct {
	Addr
	Pos OperandPos
}

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

type AddrType added in go1.7 

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 added in go1.8 

func (i AddrType) String() string

type As added in go1.7 

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 added in go1.8 

func (a As) String() string

type Attribute added in go1.8 

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 added in go1.12 

func (a Attribute) ABI() ABI

func (Attribute) CFunc added in go1.8 

func (a Attribute) CFunc() bool

func (Attribute) ContentAddressable added in go1.16 

func (a Attribute) ContentAddressable() bool

func (Attribute) DuplicateOK added in go1.8 

func (a Attribute) DuplicateOK() bool

func (Attribute) Indexed added in go1.14 

func (a Attribute) Indexed() bool

func (Attribute) Leaf added in go1.8 

func (a Attribute) Leaf() bool

func (Attribute) Local added in go1.8 

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

func (Attribute) NeedCtxt added in go1.9 

func (a Attribute) NeedCtxt() bool

func (Attribute) NoFrame added in go1.9 

func (a Attribute) NoFrame() bool

func (Attribute) NoSplit added in go1.8 

func (a Attribute) NoSplit() bool

func (Attribute) OnList added in go1.8 

func (a Attribute) OnList() bool

func (Attribute) ReflectMethod added in go1.8 

func (a Attribute) ReflectMethod() bool

func (*Attribute) Set added in go1.8 

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

func (*Attribute) SetABI added in go1.12 

func (a *Attribute) SetABI(abi ABI)

func (Attribute) Static added in go1.9 

func (a Attribute) Static() bool

func (Attribute) TextAttrString added in go1.9 

func (a Attribute) TextAttrString() string

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

func (Attribute) TopFrame added in go1.13 

func (a Attribute) TopFrame() bool

func (Attribute) UsedInIface added in go1.16 

func (a Attribute) UsedInIface() bool

func (Attribute) WasInlined added in go1.10 

func (a Attribute) WasInlined() bool

func (Attribute) Wrapper added in go1.9 

func (a Attribute) Wrapper() bool

type Auto 

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

type BySymName added in go1.14 

type BySymName []*LSym

func (BySymName) Len added in go1.14 

func (s BySymName) Len() int

func (BySymName) Less added in go1.14 

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

func (BySymName) Swap added in go1.14 

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

type DwarfFixupTable added in go1.10 

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 added in go1.10 

func NewDwarfFixupTable(ctxt *Link) *DwarfFixupTable

func (*DwarfFixupTable) AbsFuncDwarfSym added in go1.10 

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

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

func (*DwarfFixupTable) Finalize added in go1.10 

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 added in go1.10 

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

func (*DwarfFixupTable) ReferenceChildDIE added in go1.10 

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 added in go1.10 

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 added in go1.10 

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

type FileInfo added in go1.16 

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 added in go1.9 

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 added in go1.12 

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 added in go1.14 

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 added in go1.12 

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

type InlTree added in go1.9 

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 added in go1.9 

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 added in go1.10 

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

func (*InlTree) InlinedFunction added in go1.10 

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

func (*InlTree) Parent added in go1.10 

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

type InlinedCall added in go1.9 

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 added in go1.15 

func (s *LSym) CanBeAnSSASym()

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

func (*LSym) File added in go1.16 

func (s *LSym) File() *FileInfo

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

func (*LSym) Func added in go1.9 

func (s *LSym) Func() *FuncInfo

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

func (*LSym) Grow added in go1.7 

func (s *LSym) Grow(lsiz int64)

Grow increases the length of s.P to lsiz.

func (*LSym) GrowCap added in go1.7 

func (s *LSym) GrowCap(c int64)

GrowCap increases the capacity of s.P to c.

func (*LSym) Length added in go1.15 

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

func (*LSym) NewFileInfo added in go1.16 

func (s *LSym) NewFileInfo() *FileInfo

NewFileInfo allocates and returns a FileInfo for LSym.

func (*LSym) NewFuncInfo added in go1.16 

func (s *LSym) NewFuncInfo() *FuncInfo

NewFuncInfo allocates and returns a FuncInfo for LSym.

func (*LSym) String added in go1.7 

func (s *LSym) String() string

func (*LSym) WriteAddr added in go1.7 

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 added in go1.7 

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 added in go1.10 

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 added in go1.7 

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

WriteFloat32 writes f into s at offset off.

func (*LSym) WriteFloat64 added in go1.7 

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

WriteFloat64 writes f into s at offset off.

func (*LSym) WriteInt added in go1.7 

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 added in go1.7 

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 added in go1.7 

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 added in go1.8 

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 added in go1.14 

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 added in go1.9 

func (ctxt *Link) CanReuseProgs() bool

func (*Link) Diag 

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

func (*Link) DwarfAbstractFunc added in go1.10 

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

func (*Link) DwarfIntConst added in go1.10 

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 added in go1.11 

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 added in go1.14 

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

Similar to EmitEntryLiveness, but just emit stack map.

func (*Link) EmitEntryUnsafePoint added in go1.16 

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

Similar to EmitEntryLiveness, but just emit unsafe point map.

func (*Link) EndUnsafePoint added in go1.14 

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 added in go1.6 

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 added in go1.9 

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

func (*Link) Float64Sym added in go1.9 

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

func (*Link) Globl added in go1.8 

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

func (*Link) InitTextSym added in go1.9 

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

func (*Link) InnermostPos added in go1.10 

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 added in go1.9 

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

func (*Link) Logf added in go1.8 

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

func (*Link) Lookup added in go1.9 

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 added in go1.12 

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 added in go1.14 

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 added in go1.9 

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 added in go1.9 

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 added in go1.9 

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 added in go1.14 

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 added in go1.9 

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 added in go1.14 

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 added in go1.16 

type OperandPos int8
const (
	Source OperandPos = iota
	Destination
)

type PCIter added in go1.14 

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 added in go1.14 

func NewPCIter(pcScale uint32) *PCIter

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

func (*PCIter) Init added in go1.14 

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

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

func (*PCIter) Next added in go1.14 

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 deprecated 

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 deprecated added in go1.10 

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 added in go1.16 

func (p *Prog) GetTo2() *Addr

GetTo2 returns the second destination operand.

func (*Prog) InnermostFilename added in go1.10 

func (p *Prog) InnermostFilename() string

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

func (*Prog) InnermostLine added in go1.12 

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

func (*Prog) InnermostLineNumber added in go1.10 

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 added in go1.11 

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 added in go1.12 

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

func (*Prog) InstructionString added in go1.10 

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 deprecated added in go1.10 

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 added in go1.16 

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

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

func (*Prog) SetTo2 added in go1.16 

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 added in go1.15 

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 added in go1.9 

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

Source Files

View all Source files

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.
 Package ppc64 implements a PPC64 assembler that assembles Go asm into the corresponding PPC64 instructions as defined by the Power ISA 3.0B.

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