obj

package
v0.0.0-...-c8b2ac6 Latest Latest
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 Go to latest Published: Oct 25, 2018 License: BSD-3-Clause Imports: 14 Imported by: 0

Documentation

Index

Constants

View Source 
const (
	ABase386 = (1 + iota) << 11
	ABaseARM
	ABaseAMD64
	ABasePPC64
	ABaseARM64
	ABaseMIPS
	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 (
	PrologueEnd   = 2 + iota // overload "is_stmt" to include prologue_end
	EpilogueBegin            // overload "is_stmt" to include epilogue_end
)
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
)
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)
	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

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

func Flushplist 

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

func Mconv 

func Mconv(a *Addr) string

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 SortSlice 

func SortSlice(slice interface{}, less func(i, j int) bool)

func WriteObjFile 

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

Types

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{}
}

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 auto that was optimized away, but whose type
	// we want to preserve in the DWARF debug info.
	NAME_DELETED_AUTO
)

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 int16

Attribute is a set of symbol attributes. 

const (
	AttrDuplicateOK Attribute = 1 << iota
	AttrCFunc
	AttrNoSplit
	AttrLeaf
	AttrWrapper
	AttrNeedCtxt
	AttrNoFrame
	AttrSeenGlobl
	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
)

func (Attribute) CFunc 

func (a Attribute) CFunc() bool

func (Attribute) DuplicateOK 

func (a Attribute) DuplicateOK() 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) SeenGlobl 

func (a Attribute) SeenGlobl() bool

func (*Attribute) Set 

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

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) 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 DwarfFixupTable 

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

This table is designed to aid in the creation of references betweeen 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 FuncInfo 

type FuncInfo struct {
	Args   int32
	Locals int32
	Text   *Prog
	Autom  []*Auto
	Pcln   Pcln

	GCArgs       LSym
	GCLocals     LSym
	GCRegs       LSym
	StackObjects *LSym
	// contains filtered or unexported fields
}

A FuncInfo contains extra fields for STEXT symbols.

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
}

InlinedCall is a node in an InlTree.

type LSym 

type LSym struct {
	Name string
	Type objabi.SymKind
	Attribute

	RefIdx int // Index of this symbol in the symbol reference list.
	Size   int64
	Gotype *LSym
	P      []byte
	R      []Reloc

	Func *FuncInfo
}

An LSym is the sort of symbol that is written to an object file.

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) Len 

func (s *LSym) Len() int64

func (*LSym) String 

func (s *LSym) String() string

The compiler needs LSym to satisfy fmt.Stringer, because it stores an LSym in ssa.ExternSymbol.

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) 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           bool
	Debugvlog          bool
	Debugpcln          string
	Flag_shared        bool
	Flag_dynlink       bool
	Flag_optimize      bool
	Flag_locationlists bool
	Bso                *bufio.Writer
	Pathname           string

	PosTable        src.PosTable
	InlTree         InlTree // global inlining tree used by gc/inl.go
	DwFixups        *DwarfFixupTable
	Imports         []string
	DiagFunc        func(string, ...interface{})
	DiagFlush       func()
	DebugInfo       func(fn *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
	Framepointer_enabled bool

	// state for writing objects
	Text []*LSym
	Data []*LSym
	// 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)

AddImport adds a package to the list of imported packages.

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) 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) 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) 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.

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 Pcdata 

type Pcdata struct {
	P []byte
}

type Pcln 

type Pcln struct {
	Pcsp        Pcdata
	Pcfile      Pcdata
	Pcline      Pcdata
	Pcinline    Pcdata
	Pcdata      []Pcdata
	Funcdata    []*LSym
	Funcdataoff []int64
	File        []string
	Lastfile    string
	Lastindex   int
	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 []Addr   // can pack any operands that not fit into {Prog.From, Prog.To}
	To       Addr     // destination operand (second is RegTo2 below)
	Pcond    *Prog    // target of conditional jump
	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 Pcond field to point to the target instruction, 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 

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) InnermostFilename 

func (p *Prog) InnermostFilename() string

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

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) 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 deprecated 

func (p *Prog) SetFrom3(a Addr)

SetFrom3 assigns []Addr{a} 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) String 

func (p *Prog) String() string

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

Source Files

View all Source files

Directories

Path Synopsis
Package arm64 implements an ARM64 assembler.
 Package arm64 implements an ARM64 assembler.

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