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go / 1.0 / reference / pkg-cmd-internal-objabi.html

Package objabi

import "cmd/internal/objabi"
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Constants

Auto.name

const (
    A_AUTO = 1 + iota
    A_PARAM
    A_DELETED_AUTO
)
const (
    PCDATA_UnsafePoint   = 0
    PCDATA_StackMapIndex = 1
    PCDATA_InlTreeIndex  = 2

    FUNCDATA_ArgsPointerMaps    = 0
    FUNCDATA_LocalsPointerMaps  = 1
    FUNCDATA_StackObjects       = 2
    FUNCDATA_InlTree            = 3
    FUNCDATA_OpenCodedDeferInfo = 4

    // ArgsSizeUnknown is set in Func.argsize to mark all functions
    // whose argument size is unknown (C vararg functions, and
    // assembly code without an explicit specification).
    // This value is generated by the compiler, assembler, or linker.
    ArgsSizeUnknown = -0x80000000
)

Special PCDATA values.

const (
    // PCDATA_UnsafePoint values.
    PCDATA_UnsafePointSafe   = -1 // Safe for async preemption
    PCDATA_UnsafePointUnsafe = -2 // Unsafe for async preemption

    // PCDATA_Restart1(2) apply on a sequence of instructions, within
    // which if an async preemption happens, we should back off the PC
    // to the start of the sequence when resuming.
    // We need two so we can distinguish the start/end of the sequence
    // in case that two sequences are next to each other.
    PCDATA_Restart1 = -3
    PCDATA_Restart2 = -4

    // Like PCDATA_Restart1, but back to function entry if async preempted.
    PCDATA_RestartAtEntry = -5
)
const (
    STACKSYSTEM = 0
    StackSystem = STACKSYSTEM
    StackBig    = 4096
    StackSmall  = 128
)
const (
    KindBool = 1 + iota
    KindInt
    KindInt8
    KindInt16
    KindInt32
    KindInt64
    KindUint
    KindUint8
    KindUint16
    KindUint32
    KindUint64
    KindUintptr
    KindFloat32
    KindFloat64
    KindComplex64
    KindComplex128
    KindArray
    KindChan
    KindFunc
    KindInterface
    KindMap
    KindPtr
    KindSlice
    KindString
    KindStruct
    KindUnsafePointer
    KindDirectIface = 1 << 5
    KindGCProg      = 1 << 6
    KindMask        = (1 << 5) - 1
)
const (
    ElfRelocOffset   = 256
    MachoRelocOffset = 2048 // reserve enough space for ELF relocations
)
const (
    StackPreempt = -1314 // 0xfff...fade
)

Variables

var (
    GOROOT   = envOr("GOROOT", defaultGOROOT)
    GOARCH   = envOr("GOARCH", defaultGOARCH)
    GOOS     = envOr("GOOS", defaultGOOS)
    GO386    = envOr("GO386", defaultGO386)
    GOARM    = goarm()
    GOMIPS   = gomips()
    GOMIPS64 = gomips64()
    GOPPC64  = goppc64()
    GOWASM   = gowasm()
    GO_LDSO  = defaultGO_LDSO
    Version  = version
)
var (
    Fieldtrack_enabled        int
    Preemptibleloops_enabled  int
    Staticlockranking_enabled int
    Regabi_enabled            int
)

Note: must agree with runtime.framepointer_enabled.

var Framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64" && (GOOS == "linux" || GOOS == "darwin" || GOOS == "ios")

Initialize StackGuard and StackLimit according to target system.

var StackGuard = 928*stackGuardMultiplier() + StackSystem
var StackLimit = StackGuard - StackSystem - StackSmall

func AbsFile 

func AbsFile(dir, file, rewrites string) string

AbsFile returns the absolute filename for file in the given directory, as rewritten by the rewrites argument. For unrewritten paths, AbsFile rewrites a leading $GOROOT prefix to the literal "$GOROOT". If the resulting path is the empty string, the result is "??".

The rewrites argument is a ;-separated list of rewrites. Each rewrite is of the form "prefix" or "prefix=>replace", where prefix must match a leading sequence of path elements and is either removed entirely or replaced by the replacement.

func AddVersionFlag 

func AddVersionFlag()

func ApplyRewrites 

func ApplyRewrites(file, rewrites string) (string, bool)

ApplyRewrites returns the filename for file in the given directory, as rewritten by the rewrites argument.

The rewrites argument is a ;-separated list of rewrites. Each rewrite is of the form "prefix" or "prefix=>replace", where prefix must match a leading sequence of path elements and is either removed entirely or replaced by the replacement.

func DecodeArg 

func DecodeArg(arg string) string

DecodeArg decodes an argument.

This function is public for testing with the parallel encoder.

func DefaultExpstring 

func DefaultExpstring() string

func Expstring 

func Expstring() string

func Flagcount 

func Flagcount(name, usage string, val *int)

func Flagfn1 

func Flagfn1(name, usage string, f func(string))

func Flagparse 

func Flagparse(usage func())

func Flagprint 

func Flagprint(w io.Writer)

func Getgoextlinkenabled 

func Getgoextlinkenabled() string

func IsRuntimePackagePath 

func IsRuntimePackagePath(pkgpath string) bool

IsRuntimePackagePath examines 'pkgpath' and returns TRUE if it belongs to the collection of "runtime-related" packages, including "runtime" itself, "reflect", "syscall", and the "runtime/internal/*" packages. The compiler and/or assembler in some cases need to be aware of when they are building such a package, for example to enable features such as ABI selectors in assembly sources.

func PathToPrefix 

func PathToPrefix(s string) string

PathToPrefix converts raw string to the prefix that will be used in the symbol table. All control characters, space, '%' and '"', as well as non-7-bit clean bytes turn into %xx. The period needs escaping only in the last segment of the path, and it makes for happier users if we escape that as little as possible.

func WorkingDir 

func WorkingDir() string

WorkingDir returns the current working directory (or "/???" if the directory cannot be identified), with "/" as separator.

type FuncID

A FuncID identifies particular functions that need to be treated specially by the runtime. Note that in some situations involving plugins, there may be multiple copies of a particular special runtime function. Note: this list must match the list in runtime/symtab.go.

type FuncID uint8
const (
    FuncID_normal FuncID = iota // not a special function
    FuncID_runtime_main
    FuncID_goexit
    FuncID_jmpdefer
    FuncID_mcall
    FuncID_morestack
    FuncID_mstart
    FuncID_rt0_go
    FuncID_asmcgocall
    FuncID_sigpanic
    FuncID_runfinq
    FuncID_gcBgMarkWorker
    FuncID_systemstack_switch
    FuncID_systemstack
    FuncID_cgocallback
    FuncID_gogo
    FuncID_externalthreadhandler
    FuncID_debugCallV1
    FuncID_gopanic
    FuncID_panicwrap
    FuncID_handleAsyncEvent
    FuncID_asyncPreempt
    FuncID_wrapper // any autogenerated code (hash/eq algorithms, method wrappers, etc.)
)

func GetFuncID 

func GetFuncID(name string, isWrapper bool) FuncID

Get the function ID for the named function in the named file. The function should be package-qualified.

type HeadType

HeadType is the executable header type.

type HeadType uint8
const (
    Hunknown HeadType = iota
    Hdarwin
    Hdragonfly
    Hfreebsd
    Hjs
    Hlinux
    Hnetbsd
    Hopenbsd
    Hplan9
    Hsolaris
    Hwindows
    Haix
)

func (*HeadType) Set 

func (h *HeadType) Set(s string) error

func (*HeadType) String 

func (h *HeadType) String() string

type RelocType 

type RelocType int16
const (
    R_ADDR RelocType = 1 + iota
    // R_ADDRPOWER relocates a pair of "D-form" instructions (instructions with 16-bit
    // immediates in the low half of the instruction word), usually addis followed by
    // another add or a load, inserting the "high adjusted" 16 bits of the address of
    // the referenced symbol into the immediate field of the first instruction and the
    // low 16 bits into that of the second instruction.
    R_ADDRPOWER
    // R_ADDRARM64 relocates an adrp, add pair to compute the address of the
    // referenced symbol.
    R_ADDRARM64
    // R_ADDRMIPS (only used on mips/mips64) resolves to the low 16 bits of an external
    // address, by encoding it into the instruction.
    R_ADDRMIPS
    // R_ADDROFF resolves to a 32-bit offset from the beginning of the section
    // holding the data being relocated to the referenced symbol.
    R_ADDROFF
    // R_WEAKADDROFF resolves just like R_ADDROFF but is a weak relocation.
    // A weak relocation does not make the symbol it refers to reachable,
    // and is only honored by the linker if the symbol is in some other way
    // reachable.
    R_WEAKADDROFF
    R_SIZE
    R_CALL
    R_CALLARM
    R_CALLARM64
    R_CALLIND
    R_CALLPOWER
    // R_CALLMIPS (only used on mips64) resolves to non-PC-relative target address
    // of a CALL (JAL) instruction, by encoding the address into the instruction.
    R_CALLMIPS
    // R_CALLRISCV marks RISC-V CALLs for stack checking.
    R_CALLRISCV
    R_CONST
    R_PCREL
    // R_TLS_LE, used on 386, amd64, and ARM, resolves to the offset of the
    // thread-local symbol from the thread local base and is used to implement the
    // "local exec" model for tls access (r.Sym is not set on intel platforms but is
    // set to a TLS symbol -- runtime.tlsg -- in the linker when externally linking).
    R_TLS_LE
    // R_TLS_IE, used 386, amd64, and ARM resolves to the PC-relative offset to a GOT
    // slot containing the offset from the thread-local symbol from the thread local
    // base and is used to implemented the "initial exec" model for tls access (r.Sym
    // is not set on intel platforms but is set to a TLS symbol -- runtime.tlsg -- in
    // the linker when externally linking).
    R_TLS_IE
    R_GOTOFF
    R_PLT0
    R_PLT1
    R_PLT2
    R_USEFIELD
    // R_USETYPE resolves to an *rtype, but no relocation is created. The
    // linker uses this as a signal that the pointed-to type information
    // should be linked into the final binary, even if there are no other
    // direct references. (This is used for types reachable by reflection.)
    R_USETYPE
    // R_USEIFACE marks a type is converted to an interface in the function this
    // relocation is applied to. The target is a type descriptor.
    // This is a marker relocation (0-sized), for the linker's reachabililty
    // analysis.
    R_USEIFACE
    // R_USEIFACEMETHOD marks an interface method that is used in the function
    // this relocation is applied to. The target is an interface type descriptor.
    // The addend is the offset of the method in the type descriptor.
    // This is a marker relocation (0-sized), for the linker's reachabililty
    // analysis.
    R_USEIFACEMETHOD
    // R_METHODOFF resolves to a 32-bit offset from the beginning of the section
    // holding the data being relocated to the referenced symbol.
    // It is a variant of R_ADDROFF used when linking from the uncommonType of a
    // *rtype, and may be set to zero by the linker if it determines the method
    // text is unreachable by the linked program.
    R_METHODOFF
    R_POWER_TOC
    R_GOTPCREL
    // R_JMPMIPS (only used on mips64) resolves to non-PC-relative target address
    // of a JMP instruction, by encoding the address into the instruction.
    // The stack nosplit check ignores this since it is not a function call.
    R_JMPMIPS

    // R_DWARFSECREF resolves to the offset of the symbol from its section.
    // Target of relocation must be size 4 (in current implementation).
    R_DWARFSECREF

    // R_DWARFFILEREF resolves to an index into the DWARF .debug_line
    // file table for the specified file symbol. Must be applied to an
    // attribute of form DW_FORM_data4.
    R_DWARFFILEREF

    // Set a MOV[NZ] immediate field to bits [15:0] of the offset from the thread
    // local base to the thread local variable defined by the referenced (thread
    // local) symbol. Error if the offset does not fit into 16 bits.
    R_ARM64_TLS_LE

    // Relocates an ADRP; LD64 instruction sequence to load the offset between
    // the thread local base and the thread local variable defined by the
    // referenced (thread local) symbol from the GOT.
    R_ARM64_TLS_IE

    // R_ARM64_GOTPCREL relocates an adrp, ld64 pair to compute the address of the GOT
    // slot of the referenced symbol.
    R_ARM64_GOTPCREL

    // R_ARM64_GOT resolves a GOT-relative instruction sequence, usually an adrp
    // followed by another ld instruction.
    R_ARM64_GOT

    // R_ARM64_PCREL resolves a PC-relative addresses instruction sequence, usually an
    // adrp followed by another add instruction.
    R_ARM64_PCREL

    // R_ARM64_LDST8 sets a LD/ST immediate value to bits [11:0] of a local address.
    R_ARM64_LDST8

    // R_ARM64_LDST16 sets a LD/ST immediate value to bits [11:1] of a local address.
    R_ARM64_LDST16

    // R_ARM64_LDST32 sets a LD/ST immediate value to bits [11:2] of a local address.
    R_ARM64_LDST32

    // R_ARM64_LDST64 sets a LD/ST immediate value to bits [11:3] of a local address.
    R_ARM64_LDST64

    // R_ARM64_LDST128 sets a LD/ST immediate value to bits [11:4] of a local address.
    R_ARM64_LDST128

    // R_POWER_TLS_LE is used to implement the "local exec" model for tls
    // access. It resolves to the offset of the thread-local symbol from the
    // thread pointer (R13) and inserts this value into the low 16 bits of an
    // instruction word.
    R_POWER_TLS_LE

    // R_POWER_TLS_IE is used to implement the "initial exec" model for tls access. It
    // relocates a D-form, DS-form instruction sequence like R_ADDRPOWER_DS. It
    // inserts to the offset of GOT slot for the thread-local symbol from the TOC (the
    // GOT slot is filled by the dynamic linker with the offset of the thread-local
    // symbol from the thread pointer (R13)).
    R_POWER_TLS_IE

    // R_POWER_TLS marks an X-form instruction such as "MOVD 0(R13)(R31*1), g" as
    // accessing a particular thread-local symbol. It does not affect code generation
    // but is used by the system linker when relaxing "initial exec" model code to
    // "local exec" model code.
    R_POWER_TLS

    // R_ADDRPOWER_DS is similar to R_ADDRPOWER above, but assumes the second
    // instruction is a "DS-form" instruction, which has an immediate field occupying
    // bits [15:2] of the instruction word. Bits [15:2] of the address of the
    // relocated symbol are inserted into this field; it is an error if the last two
    // bits of the address are not 0.
    R_ADDRPOWER_DS

    // R_ADDRPOWER_PCREL relocates a D-form, DS-form instruction sequence like
    // R_ADDRPOWER_DS but inserts the offset of the GOT slot for the referenced symbol
    // from the TOC rather than the symbol's address.
    R_ADDRPOWER_GOT

    // R_ADDRPOWER_PCREL relocates two D-form instructions like R_ADDRPOWER, but
    // inserts the displacement from the place being relocated to the address of the
    // relocated symbol instead of just its address.
    R_ADDRPOWER_PCREL

    // R_ADDRPOWER_TOCREL relocates two D-form instructions like R_ADDRPOWER, but
    // inserts the offset from the TOC to the address of the relocated symbol
    // rather than the symbol's address.
    R_ADDRPOWER_TOCREL

    // R_ADDRPOWER_TOCREL relocates a D-form, DS-form instruction sequence like
    // R_ADDRPOWER_DS but inserts the offset from the TOC to the address of the
    // relocated symbol rather than the symbol's address.
    R_ADDRPOWER_TOCREL_DS

    // R_RISCV_PCREL_ITYPE resolves a 32-bit PC-relative address using an
    // AUIPC + I-type instruction pair.
    R_RISCV_PCREL_ITYPE

    // R_RISCV_PCREL_STYPE resolves a 32-bit PC-relative address using an
    // AUIPC + S-type instruction pair.
    R_RISCV_PCREL_STYPE

    // R_RISCV_TLS_IE_ITYPE resolves a 32-bit TLS initial-exec TOC offset
    // address using an AUIPC + I-type instruction pair.
    R_RISCV_TLS_IE_ITYPE

    // R_RISCV_TLS_IE_STYPE resolves a 32-bit TLS initial-exec TOC offset
    // address using an AUIPC + S-type instruction pair.
    R_RISCV_TLS_IE_STYPE

    // R_PCRELDBL relocates s390x 2-byte aligned PC-relative addresses.
    // TODO(mundaym): remove once variants can be serialized - see issue 14218.
    R_PCRELDBL

    // R_ADDRMIPSU (only used on mips/mips64) resolves to the sign-adjusted "upper" 16
    // bits (bit 16-31) of an external address, by encoding it into the instruction.
    R_ADDRMIPSU
    // R_ADDRMIPSTLS (only used on mips64) resolves to the low 16 bits of a TLS
    // address (offset from thread pointer), by encoding it into the instruction.
    R_ADDRMIPSTLS

    // R_ADDRCUOFF resolves to a pointer-sized offset from the start of the
    // symbol's DWARF compile unit.
    R_ADDRCUOFF

    // R_WASMIMPORT resolves to the index of the WebAssembly function import.
    R_WASMIMPORT

    // R_XCOFFREF (only used on aix/ppc64) prevents garbage collection by ld
    // of a symbol. This isn't a real relocation, it can be placed in anywhere
    // in a symbol and target any symbols.
    R_XCOFFREF
)

func (RelocType) IsDirectCall 

func (r RelocType) IsDirectCall() bool

IsDirectCall reports whether r is a relocation for a direct call. A direct call is a CALL instruction that takes the target address as an immediate. The address is embedded into the instruction, possibly with limited width. An indirect call is a CALL instruction that takes the target address in register or memory.

func (RelocType) IsDirectCallOrJump 

func (r RelocType) IsDirectCallOrJump() bool

IsDirectCallOrJump reports whether r is a relocation for a direct call or a direct jump.

func (RelocType) IsDirectJump 

func (r RelocType) IsDirectJump() bool

IsDirectJump reports whether r is a relocation for a direct jump. A direct jump is a JMP instruction that takes the target address as an immediate. The address is embedded into the instruction, possibly with limited width. An indirect jump is a JMP instruction that takes the target address in register or memory.

func (RelocType) String 

func (i RelocType) String() string

type SymKind

A SymKind describes the kind of memory represented by a symbol.

type SymKind uint8

Defined SymKind values. These are used to index into cmd/link/internal/sym/AbiSymKindToSymKind

TODO(rsc): Give idiomatic Go names.

const (
    // An otherwise invalid zero value for the type
    Sxxx SymKind = iota
    // Executable instructions
    STEXT
    // Read only static data
    SRODATA
    // Static data that does not contain any pointers
    SNOPTRDATA
    // Static data
    SDATA
    // Statically data that is initially all 0s
    SBSS
    // Statically data that is initially all 0s and does not contain pointers
    SNOPTRBSS
    // Thread-local data that is initially all 0s
    STLSBSS
    // Debugging data
    SDWARFCUINFO
    SDWARFCONST
    SDWARFFCN
    SDWARFABSFCN
    SDWARFTYPE
    SDWARFVAR
    SDWARFRANGE
    SDWARFLOC
    SDWARFLINES
    // ABI alias. An ABI alias symbol is an empty symbol with a
    // single relocation with 0 size that references the native
    // function implementation symbol.
    //
    // TODO(austin): Remove this and all uses once the compiler
    // generates real ABI wrappers rather than symbol aliases.
    SABIALIAS
    // Coverage instrumentation counter for libfuzzer.
    SLIBFUZZER_EXTRA_COUNTER
)

func (SymKind) String 

func (i SymKind) String() string