site/vendor/github.com/google/gops/internal/obj/link.go

975 lines
28 KiB
Go

// Derived from Inferno utils/6l/l.h and related files.
// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/l.h
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
// Portions Copyright © 1997-1999 Vita Nuova Limited
// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
// Portions Copyright © 2004,2006 Bruce Ellis
// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
// Portions Copyright © 2009 The Go Authors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package obj
import (
"bufio"
"fmt"
"github.com/google/gops/internal/sys"
)
// An Addr is an argument to an instruction.
// The general forms and their encodings are:
//
// sym±offset(symkind)(reg)(index*scale)
// Memory reference at address &sym(symkind) + offset + reg + index*scale.
// Any of sym(symkind), ±offset, (reg), (index*scale), and *scale can be omitted.
// If (reg) and *scale are both omitted, the resulting expression (index) is parsed as (reg).
// To force a parsing as index*scale, write (index*1).
// Encoding:
// type = TYPE_MEM
// name = symkind (NAME_AUTO, ...) or 0 (NAME_NONE)
// sym = sym
// offset = ±offset
// reg = reg (REG_*)
// index = index (REG_*)
// scale = scale (1, 2, 4, 8)
//
// $<mem>
// Effective address of memory reference <mem>, defined above.
// Encoding: same as memory reference, but type = TYPE_ADDR.
//
// $<±integer value>
// This is a special case of $<mem>, in which only ±offset is present.
// It has a separate type for easy recognition.
// Encoding:
// type = TYPE_CONST
// offset = ±integer value
//
// *<mem>
// Indirect reference through memory reference <mem>, defined above.
// Only used on x86 for CALL/JMP *sym(SB), which calls/jumps to a function
// pointer stored in the data word sym(SB), not a function named sym(SB).
// Encoding: same as above, but type = TYPE_INDIR.
//
// $*$<mem>
// No longer used.
// On machines with actual SB registers, $*$<mem> forced the
// instruction encoding to use a full 32-bit constant, never a
// reference relative to SB.
//
// $<floating point literal>
// Floating point constant value.
// Encoding:
// type = TYPE_FCONST
// val = floating point value
//
// $<string literal, up to 8 chars>
// String literal value (raw bytes used for DATA instruction).
// Encoding:
// type = TYPE_SCONST
// val = string
//
// <register name>
// Any register: integer, floating point, control, segment, and so on.
// If looking for specific register kind, must check type and reg value range.
// Encoding:
// type = TYPE_REG
// reg = reg (REG_*)
//
// x(PC)
// Encoding:
// type = TYPE_BRANCH
// val = Prog* reference OR ELSE offset = target pc (branch takes priority)
//
// $±x-±y
// Final argument to TEXT, specifying local frame size x and argument size y.
// In this form, x and y are integer literals only, not arbitrary expressions.
// This avoids parsing ambiguities due to the use of - as a separator.
// The ± are optional.
// If the final argument to TEXT omits the -±y, the encoding should still
// use TYPE_TEXTSIZE (not TYPE_CONST), with u.argsize = ArgsSizeUnknown.
// Encoding:
// type = TYPE_TEXTSIZE
// offset = x
// val = int32(y)
//
// reg<<shift, reg>>shift, reg->shift, reg@>shift
// Shifted register value, for ARM and ARM64.
// In this form, reg must be a register and shift can be a register or an integer constant.
// Encoding:
// type = TYPE_SHIFT
// On ARM:
// offset = (reg&15) | shifttype<<5 | count
// shifttype = 0, 1, 2, 3 for <<, >>, ->, @>
// count = (reg&15)<<8 | 1<<4 for a register shift count, (n&31)<<7 for an integer constant.
// On ARM64:
// offset = (reg&31)<<16 | shifttype<<22 | (count&63)<<10
// shifttype = 0, 1, 2 for <<, >>, ->
//
// (reg, reg)
// A destination register pair. When used as the last argument of an instruction,
// this form makes clear that both registers are destinations.
// Encoding:
// type = TYPE_REGREG
// reg = first register
// offset = second register
//
// [reg, reg, reg-reg]
// Register list for ARM.
// Encoding:
// type = TYPE_REGLIST
// offset = bit mask of registers in list; R0 is low bit.
//
// reg, reg
// Register pair for ARM.
// TYPE_REGREG2
//
// (reg+reg)
// Register pair for PPC64.
// Encoding:
// type = TYPE_MEM
// reg = first register
// index = second register
// scale = 1
//
type Addr struct {
Reg int16
Index int16
Scale int16 // Sometimes holds a register.
Type AddrType
Name int8
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{}
Node interface{} // for use by compiler
}
type AddrType uint8
const (
NAME_NONE = 0 + 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
)
const (
TYPE_NONE AddrType = 0
TYPE_BRANCH AddrType = 5 + iota
TYPE_TEXTSIZE
TYPE_MEM
TYPE_CONST
TYPE_FCONST
TYPE_SCONST
TYPE_REG
TYPE_ADDR
TYPE_SHIFT
TYPE_REGREG
TYPE_REGREG2
TYPE_INDIR
TYPE_REGLIST
)
// Prog describes a single machine instruction.
//
// The general instruction form is:
//
// As.Scond From, Reg, From3, To, RegTo2
//
// where As is an opcode and the others are arguments:
// From, Reg, From3 are sources, and To, RegTo2 are 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.
//
// 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 Lineno, an index into the line history (see LineHist).
// Every Prog has a Ctxt field that defines various context, including the current LineHist.
// Progs should be allocated using ctxt.NewProg(), not 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.
type Prog struct {
Ctxt *Link // linker context
Link *Prog // next Prog in linked list
From Addr // first source operand
From3 *Addr // third source operand (second is Reg below)
To Addr // destination operand (second is RegTo2 below)
Pcond *Prog // target of conditional jump
Opt interface{} // available to optimization passes to hold per-Prog state
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
Lineno int32 // line number 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 // condition bits for conditional instruction (e.g., on ARM)
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
Mode int8 // for x86 back end: 32- or 64-bit mode
}
// From3Type returns From3.Type, or TYPE_NONE when From3 is nil.
func (p *Prog) From3Type() AddrType {
if p.From3 == nil {
return TYPE_NONE
}
return p.From3.Type
}
// From3Offset returns From3.Offset, or 0 when From3 is nil.
func (p *Prog) From3Offset() int64 {
if p.From3 == nil {
return 0
}
return p.From3.Offset
}
// 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.
type As int16
// These are the portable opcodes.
const (
AXXX As = iota
ACALL
ADUFFCOPY
ADUFFZERO
AEND
AFUNCDATA
AJMP
ANOP
APCDATA
ARET
ATEXT
ATYPE
AUNDEF
AUSEFIELD
AVARDEF
AVARKILL
AVARLIVE
A_ARCHSPECIFIC
)
// 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.
const (
ABase386 = (1 + iota) << 10
ABaseARM
ABaseAMD64
ABasePPC64
ABaseARM64
ABaseMIPS64
ABaseS390X
AllowedOpCodes = 1 << 10 // The number of opcodes available for any given architecture.
AMask = AllowedOpCodes - 1 // AND with this to use the opcode as an array index.
)
// An LSym is the sort of symbol that is written to an object file.
type LSym struct {
Name string
Type SymKind
Version int16
Attribute
RefIdx int // Index of this symbol in the symbol reference list.
Args int32
Locals int32
Size int64
Gotype *LSym
Autom *Auto
Text *Prog
Pcln *Pcln
P []byte
R []Reloc
}
// Attribute is a set of symbol attributes.
type Attribute int16
const (
AttrDuplicateOK Attribute = 1 << iota
AttrCFunc
AttrNoSplit
AttrLeaf
AttrSeenGlobl
AttrOnList
// 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
)
func (a Attribute) DuplicateOK() bool { return a&AttrDuplicateOK != 0 }
func (a Attribute) MakeTypelink() bool { return a&AttrMakeTypelink != 0 }
func (a Attribute) CFunc() bool { return a&AttrCFunc != 0 }
func (a Attribute) NoSplit() bool { return a&AttrNoSplit != 0 }
func (a Attribute) Leaf() bool { return a&AttrLeaf != 0 }
func (a Attribute) SeenGlobl() bool { return a&AttrSeenGlobl != 0 }
func (a Attribute) OnList() bool { return a&AttrOnList != 0 }
func (a Attribute) ReflectMethod() bool { return a&AttrReflectMethod != 0 }
func (a Attribute) Local() bool { return a&AttrLocal != 0 }
func (a *Attribute) Set(flag Attribute, value bool) {
if value {
*a |= flag
} else {
*a &^= flag
}
}
// The compiler needs LSym to satisfy fmt.Stringer, because it stores
// an LSym in ssa.ExternSymbol.
func (s *LSym) String() string {
return s.Name
}
type Pcln struct {
Pcsp Pcdata
Pcfile Pcdata
Pcline Pcdata
Pcdata []Pcdata
Funcdata []*LSym
Funcdataoff []int64
File []*LSym
Lastfile *LSym
Lastindex int
}
// A SymKind describes the kind of memory represented by a symbol.
type SymKind int16
// Defined SymKind values.
//
// TODO(rsc): Give idiomatic Go names.
// TODO(rsc): Reduce the number of symbol types in the object files.
//go:generate stringer -type=SymKind
const (
Sxxx SymKind = iota
STEXT
SELFRXSECT
// Read-only sections.
STYPE
SSTRING
SGOSTRING
SGOFUNC
SGCBITS
SRODATA
SFUNCTAB
SELFROSECT
SMACHOPLT
// Read-only sections with relocations.
//
// Types STYPE-SFUNCTAB above are written to the .rodata section by default.
// When linking a shared object, some conceptually "read only" types need to
// be written to by relocations and putting them in a section called
// ".rodata" interacts poorly with the system linkers. The GNU linkers
// support this situation by arranging for sections of the name
// ".data.rel.ro.XXX" to be mprotected read only by the dynamic linker after
// relocations have applied, so when the Go linker is creating a shared
// object it checks all objects of the above types and bumps any object that
// has a relocation to it to the corresponding type below, which are then
// written to sections with appropriate magic names.
STYPERELRO
SSTRINGRELRO
SGOSTRINGRELRO
SGOFUNCRELRO
SGCBITSRELRO
SRODATARELRO
SFUNCTABRELRO
// Part of .data.rel.ro if it exists, otherwise part of .rodata.
STYPELINK
SITABLINK
SSYMTAB
SPCLNTAB
// Writable sections.
SELFSECT
SMACHO
SMACHOGOT
SWINDOWS
SELFGOT
SNOPTRDATA
SINITARR
SDATA
SBSS
SNOPTRBSS
STLSBSS
SXREF
SMACHOSYMSTR
SMACHOSYMTAB
SMACHOINDIRECTPLT
SMACHOINDIRECTGOT
SFILE
SFILEPATH
SCONST
SDYNIMPORT
SHOSTOBJ
SDWARFSECT
SDWARFINFO
SSUB = SymKind(1 << 8)
SMASK = SymKind(SSUB - 1)
SHIDDEN = SymKind(1 << 9)
SCONTAINER = SymKind(1 << 10) // has a sub-symbol
)
// ReadOnly are the symbol kinds that form read-only sections. In some
// cases, if they will require relocations, they are transformed into
// rel-ro sections using RelROMap.
var ReadOnly = []SymKind{
STYPE,
SSTRING,
SGOSTRING,
SGOFUNC,
SGCBITS,
SRODATA,
SFUNCTAB,
}
// RelROMap describes the transformation of read-only symbols to rel-ro
// symbols.
var RelROMap = map[SymKind]SymKind{
STYPE: STYPERELRO,
SSTRING: SSTRINGRELRO,
SGOSTRING: SGOSTRINGRELRO,
SGOFUNC: SGOFUNCRELRO,
SGCBITS: SGCBITSRELRO,
SRODATA: SRODATARELRO,
SFUNCTAB: SFUNCTABRELRO,
}
type Reloc struct {
Off int32
Siz uint8
Type RelocType
Add int64
Sym *LSym
}
type RelocType int32
//go:generate stringer -type=RelocType
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 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_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_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_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_DWARFREF resolves to the offset of the symbol from its section.
R_DWARFREF
// Platform dependent relocations. Architectures with fixed width instructions
// have the inherent issue that a 32-bit (or 64-bit!) displacement cannot be
// stuffed into a 32-bit instruction, so an address needs to be spread across
// several instructions, and in turn this requires a sequence of relocations, each
// updating a part of an instruction. This leads to relocation codes that are
// inherently processor specific.
// Arm64.
// 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
// PPC64.
// 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
// 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 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 the
// relocated symbol rather than the symbol's address.
R_ADDRPOWER_TOCREL_DS
// 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 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
)
// IsDirectJump returns whether r is a relocation for a direct jump.
// A direct jump is a CALL or JMP instruction that takes the target address
// as immediate. The address is embedded into the instruction, possibly
// with limited width.
// An indirect jump is a CALL or JMP instruction that takes the target address
// in register or memory.
func (r RelocType) IsDirectJump() bool {
switch r {
case R_CALL, R_CALLARM, R_CALLARM64, R_CALLPOWER, R_CALLMIPS, R_JMPMIPS:
return true
}
return false
}
type Auto struct {
Asym *LSym
Link *Auto
Aoffset int32
Name int16
Gotype *LSym
}
// Auto.name
const (
A_AUTO = 1 + iota
A_PARAM
)
type Pcdata struct {
P []byte
}
// symbol version, incremented each time a file is loaded.
// version==1 is reserved for savehist.
const (
HistVersion = 1
)
// Link holds the context for writing object code from a compiler
// to be linker input or for reading that input into the linker.
type Link struct {
Headtype HeadType
Arch *LinkArch
Debugasm int32
Debugvlog int32
Debugdivmod int32
Debugpcln int32
Flag_shared bool
Flag_dynlink bool
Flag_optimize bool
Bso *bufio.Writer
Pathname string
Hash map[SymVer]*LSym
LineHist LineHist
Imports []string
Plists []*Plist
Sym_div *LSym
Sym_divu *LSym
Sym_mod *LSym
Sym_modu *LSym
Plan9privates *LSym
Curp *Prog
Printp *Prog
Blitrl *Prog
Elitrl *Prog
Rexflag int
Vexflag int
Rep int
Repn int
Lock int
Asmode int
AsmBuf AsmBuf // instruction buffer for x86
Instoffset int64
Autosize int32
Armsize int32
Pc int64
DiagFunc func(string, ...interface{})
Mode int
Cursym *LSym
Version int
Errors int
Framepointer_enabled bool
// state for writing objects
Text []*LSym
Data []*LSym
// Cache of Progs
allocIdx int
progs [10000]Prog
}
func (ctxt *Link) Diag(format string, args ...interface{}) {
ctxt.Errors++
ctxt.DiagFunc(format, args...)
}
func (ctxt *Link) Logf(format string, args ...interface{}) {
fmt.Fprintf(ctxt.Bso, format, args...)
ctxt.Bso.Flush()
}
// 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 (ctxt *Link) FixedFrameSize() int64 {
switch ctxt.Arch.Family {
case sys.AMD64, sys.I386:
return 0
case sys.PPC64:
// PIC code on ppc64le requires 32 bytes of stack, and it's easier to
// just use that much stack always on ppc64x.
return int64(4 * ctxt.Arch.PtrSize)
default:
return int64(ctxt.Arch.PtrSize)
}
}
type SymVer struct {
Name string
Version int // TODO: make int16 to match LSym.Version?
}
// LinkArch is the definition of a single architecture.
type LinkArch struct {
*sys.Arch
Preprocess func(*Link, *LSym)
Assemble func(*Link, *LSym)
Follow func(*Link, *LSym)
Progedit func(*Link, *Prog)
UnaryDst map[As]bool // Instruction takes one operand, a destination.
}
// HeadType is the executable header type.
type HeadType uint8
const (
Hunknown HeadType = iota
Hdarwin
Hdragonfly
Hfreebsd
Hlinux
Hnacl
Hnetbsd
Hopenbsd
Hplan9
Hsolaris
Hwindows
Hwindowsgui
)
func (h *HeadType) Set(s string) error {
switch s {
case "darwin":
*h = Hdarwin
case "dragonfly":
*h = Hdragonfly
case "freebsd":
*h = Hfreebsd
case "linux", "android":
*h = Hlinux
case "nacl":
*h = Hnacl
case "netbsd":
*h = Hnetbsd
case "openbsd":
*h = Hopenbsd
case "plan9":
*h = Hplan9
case "solaris":
*h = Hsolaris
case "windows":
*h = Hwindows
case "windowsgui":
*h = Hwindowsgui
default:
return fmt.Errorf("invalid headtype: %q", s)
}
return nil
}
func (h *HeadType) String() string {
switch *h {
case Hdarwin:
return "darwin"
case Hdragonfly:
return "dragonfly"
case Hfreebsd:
return "freebsd"
case Hlinux:
return "linux"
case Hnacl:
return "nacl"
case Hnetbsd:
return "netbsd"
case Hopenbsd:
return "openbsd"
case Hplan9:
return "plan9"
case Hsolaris:
return "solaris"
case Hwindows:
return "windows"
case Hwindowsgui:
return "windowsgui"
}
return fmt.Sprintf("HeadType(%d)", *h)
}
// AsmBuf is a simple buffer to assemble variable-length x86 instructions into.
type AsmBuf struct {
buf [100]byte
off int
}
// Put1 appends one byte to the end of the buffer.
func (a *AsmBuf) Put1(x byte) {
a.buf[a.off] = x
a.off++
}
// Put2 appends two bytes to the end of the buffer.
func (a *AsmBuf) Put2(x, y byte) {
a.buf[a.off+0] = x
a.buf[a.off+1] = y
a.off += 2
}
// Put3 appends three bytes to the end of the buffer.
func (a *AsmBuf) Put3(x, y, z byte) {
a.buf[a.off+0] = x
a.buf[a.off+1] = y
a.buf[a.off+2] = z
a.off += 3
}
// Put4 appends four bytes to the end of the buffer.
func (a *AsmBuf) Put4(x, y, z, w byte) {
a.buf[a.off+0] = x
a.buf[a.off+1] = y
a.buf[a.off+2] = z
a.buf[a.off+3] = w
a.off += 4
}
// PutInt16 writes v into the buffer using little-endian encoding.
func (a *AsmBuf) PutInt16(v int16) {
a.buf[a.off+0] = byte(v)
a.buf[a.off+1] = byte(v >> 8)
a.off += 2
}
// PutInt32 writes v into the buffer using little-endian encoding.
func (a *AsmBuf) PutInt32(v int32) {
a.buf[a.off+0] = byte(v)
a.buf[a.off+1] = byte(v >> 8)
a.buf[a.off+2] = byte(v >> 16)
a.buf[a.off+3] = byte(v >> 24)
a.off += 4
}
// PutInt64 writes v into the buffer using little-endian encoding.
func (a *AsmBuf) PutInt64(v int64) {
a.buf[a.off+0] = byte(v)
a.buf[a.off+1] = byte(v >> 8)
a.buf[a.off+2] = byte(v >> 16)
a.buf[a.off+3] = byte(v >> 24)
a.buf[a.off+4] = byte(v >> 32)
a.buf[a.off+5] = byte(v >> 40)
a.buf[a.off+6] = byte(v >> 48)
a.buf[a.off+7] = byte(v >> 56)
a.off += 8
}
// Put copies b into the buffer.
func (a *AsmBuf) Put(b []byte) {
copy(a.buf[a.off:], b)
a.off += len(b)
}
// Insert inserts b at offset i.
func (a *AsmBuf) Insert(i int, b byte) {
a.off++
copy(a.buf[i+1:a.off], a.buf[i:a.off-1])
a.buf[i] = b
}
// Last returns the byte at the end of the buffer.
func (a *AsmBuf) Last() byte { return a.buf[a.off-1] }
// Len returns the length of the buffer.
func (a *AsmBuf) Len() int { return a.off }
// Bytes returns the contents of the buffer.
func (a *AsmBuf) Bytes() []byte { return a.buf[:a.off] }
// Reset empties the buffer.
func (a *AsmBuf) Reset() { a.off = 0 }
// Peek returns the byte at offset i.
func (a *AsmBuf) Peek(i int) byte { return a.buf[i] }