975 lines
28 KiB
Go
975 lines
28 KiB
Go
// Derived from Inferno utils/6l/l.h and related files.
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// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/6l/l.h
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//
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// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
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// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
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// Portions Copyright © 1997-1999 Vita Nuova Limited
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// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
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// Portions Copyright © 2004,2006 Bruce Ellis
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// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
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// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
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// Portions Copyright © 2009 The Go Authors. All rights reserved.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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package obj
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import (
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"bufio"
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"fmt"
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"github.com/google/gops/internal/sys"
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)
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// An Addr is an argument to an instruction.
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// The general forms and their encodings are:
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//
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// sym±offset(symkind)(reg)(index*scale)
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// Memory reference at address &sym(symkind) + offset + reg + index*scale.
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// Any of sym(symkind), ±offset, (reg), (index*scale), and *scale can be omitted.
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// If (reg) and *scale are both omitted, the resulting expression (index) is parsed as (reg).
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// To force a parsing as index*scale, write (index*1).
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// Encoding:
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// type = TYPE_MEM
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// name = symkind (NAME_AUTO, ...) or 0 (NAME_NONE)
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// sym = sym
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// offset = ±offset
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// reg = reg (REG_*)
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// index = index (REG_*)
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// scale = scale (1, 2, 4, 8)
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//
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// $<mem>
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// Effective address of memory reference <mem>, defined above.
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// Encoding: same as memory reference, but type = TYPE_ADDR.
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//
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// $<±integer value>
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// This is a special case of $<mem>, in which only ±offset is present.
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// It has a separate type for easy recognition.
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// Encoding:
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// type = TYPE_CONST
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// offset = ±integer value
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//
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// *<mem>
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// Indirect reference through memory reference <mem>, defined above.
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// Only used on x86 for CALL/JMP *sym(SB), which calls/jumps to a function
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// pointer stored in the data word sym(SB), not a function named sym(SB).
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// Encoding: same as above, but type = TYPE_INDIR.
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//
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// $*$<mem>
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// No longer used.
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// On machines with actual SB registers, $*$<mem> forced the
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// instruction encoding to use a full 32-bit constant, never a
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// reference relative to SB.
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//
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// $<floating point literal>
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// Floating point constant value.
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// Encoding:
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// type = TYPE_FCONST
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// val = floating point value
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//
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// $<string literal, up to 8 chars>
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// String literal value (raw bytes used for DATA instruction).
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// Encoding:
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// type = TYPE_SCONST
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// val = string
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//
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// <register name>
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// Any register: integer, floating point, control, segment, and so on.
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// If looking for specific register kind, must check type and reg value range.
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// Encoding:
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// type = TYPE_REG
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// reg = reg (REG_*)
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//
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// x(PC)
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// Encoding:
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// type = TYPE_BRANCH
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// val = Prog* reference OR ELSE offset = target pc (branch takes priority)
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//
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// $±x-±y
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// Final argument to TEXT, specifying local frame size x and argument size y.
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// In this form, x and y are integer literals only, not arbitrary expressions.
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// This avoids parsing ambiguities due to the use of - as a separator.
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// The ± are optional.
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// If the final argument to TEXT omits the -±y, the encoding should still
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// use TYPE_TEXTSIZE (not TYPE_CONST), with u.argsize = ArgsSizeUnknown.
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// Encoding:
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// type = TYPE_TEXTSIZE
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// offset = x
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// val = int32(y)
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//
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// reg<<shift, reg>>shift, reg->shift, reg@>shift
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// Shifted register value, for ARM and ARM64.
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// In this form, reg must be a register and shift can be a register or an integer constant.
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// Encoding:
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// type = TYPE_SHIFT
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// On ARM:
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// offset = (reg&15) | shifttype<<5 | count
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// shifttype = 0, 1, 2, 3 for <<, >>, ->, @>
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// count = (reg&15)<<8 | 1<<4 for a register shift count, (n&31)<<7 for an integer constant.
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// On ARM64:
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// offset = (reg&31)<<16 | shifttype<<22 | (count&63)<<10
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// shifttype = 0, 1, 2 for <<, >>, ->
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//
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// (reg, reg)
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// A destination register pair. When used as the last argument of an instruction,
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// this form makes clear that both registers are destinations.
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// Encoding:
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// type = TYPE_REGREG
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// reg = first register
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// offset = second register
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//
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// [reg, reg, reg-reg]
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// Register list for ARM.
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// Encoding:
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// type = TYPE_REGLIST
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// offset = bit mask of registers in list; R0 is low bit.
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//
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// reg, reg
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// Register pair for ARM.
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// TYPE_REGREG2
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//
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// (reg+reg)
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// Register pair for PPC64.
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// Encoding:
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// type = TYPE_MEM
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// reg = first register
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// index = second register
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// scale = 1
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//
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type Addr struct {
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Reg int16
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Index int16
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Scale int16 // Sometimes holds a register.
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Type AddrType
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Name int8
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Class int8
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Offset int64
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Sym *LSym
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// argument value:
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// for TYPE_SCONST, a string
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// for TYPE_FCONST, a float64
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// for TYPE_BRANCH, a *Prog (optional)
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// for TYPE_TEXTSIZE, an int32 (optional)
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Val interface{}
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Node interface{} // for use by compiler
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}
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type AddrType uint8
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const (
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NAME_NONE = 0 + iota
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NAME_EXTERN
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NAME_STATIC
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NAME_AUTO
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NAME_PARAM
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// A reference to name@GOT(SB) is a reference to the entry in the global offset
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// table for 'name'.
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NAME_GOTREF
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)
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const (
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TYPE_NONE AddrType = 0
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TYPE_BRANCH AddrType = 5 + iota
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TYPE_TEXTSIZE
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TYPE_MEM
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TYPE_CONST
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TYPE_FCONST
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TYPE_SCONST
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TYPE_REG
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TYPE_ADDR
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TYPE_SHIFT
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TYPE_REGREG
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TYPE_REGREG2
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TYPE_INDIR
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TYPE_REGLIST
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)
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// Prog describes a single machine instruction.
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//
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// The general instruction form is:
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//
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// As.Scond From, Reg, From3, To, RegTo2
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//
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// where As is an opcode and the others are arguments:
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// From, Reg, From3 are sources, and To, RegTo2 are destinations.
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// Usually, not all arguments are present.
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// For example, MOVL R1, R2 encodes using only As=MOVL, From=R1, To=R2.
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// The Scond field holds additional condition bits for systems (like arm)
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// that have generalized conditional execution.
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//
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// Jump instructions use the Pcond field to point to the target instruction,
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// which must be in the same linked list as the jump instruction.
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//
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// The Progs for a given function are arranged in a list linked through the Link field.
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//
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// Each Prog is charged to a specific source line in the debug information,
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// specified by Lineno, an index into the line history (see LineHist).
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// Every Prog has a Ctxt field that defines various context, including the current LineHist.
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// Progs should be allocated using ctxt.NewProg(), not new(Prog).
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//
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// The other fields not yet mentioned are for use by the back ends and should
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// be left zeroed by creators of Prog lists.
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type Prog struct {
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Ctxt *Link // linker context
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Link *Prog // next Prog in linked list
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From Addr // first source operand
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From3 *Addr // third source operand (second is Reg below)
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To Addr // destination operand (second is RegTo2 below)
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Pcond *Prog // target of conditional jump
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Opt interface{} // available to optimization passes to hold per-Prog state
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Forwd *Prog // for x86 back end
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Rel *Prog // for x86, arm back ends
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Pc int64 // for back ends or assembler: virtual or actual program counter, depending on phase
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Lineno int32 // line number of this instruction
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Spadj int32 // effect of instruction on stack pointer (increment or decrement amount)
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As As // assembler opcode
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Reg int16 // 2nd source operand
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RegTo2 int16 // 2nd destination operand
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Mark uint16 // bitmask of arch-specific items
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Optab uint16 // arch-specific opcode index
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Scond uint8 // condition bits for conditional instruction (e.g., on ARM)
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Back uint8 // for x86 back end: backwards branch state
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Ft uint8 // for x86 back end: type index of Prog.From
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Tt uint8 // for x86 back end: type index of Prog.To
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Isize uint8 // for x86 back end: size of the instruction in bytes
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Mode int8 // for x86 back end: 32- or 64-bit mode
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}
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// From3Type returns From3.Type, or TYPE_NONE when From3 is nil.
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func (p *Prog) From3Type() AddrType {
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if p.From3 == nil {
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return TYPE_NONE
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}
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return p.From3.Type
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}
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// From3Offset returns From3.Offset, or 0 when From3 is nil.
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func (p *Prog) From3Offset() int64 {
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if p.From3 == nil {
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return 0
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}
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return p.From3.Offset
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}
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// An As denotes an assembler opcode.
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// There are some portable opcodes, declared here in package obj,
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// that are common to all architectures.
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// However, the majority of opcodes are arch-specific
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// and are declared in their respective architecture's subpackage.
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type As int16
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// These are the portable opcodes.
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const (
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AXXX As = iota
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ACALL
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ADUFFCOPY
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ADUFFZERO
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AEND
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AFUNCDATA
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AJMP
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ANOP
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APCDATA
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ARET
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ATEXT
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ATYPE
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AUNDEF
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AUSEFIELD
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AVARDEF
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AVARKILL
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AVARLIVE
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A_ARCHSPECIFIC
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)
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// Each architecture is allotted a distinct subspace of opcode values
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// for declaring its arch-specific opcodes.
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// Within this subspace, the first arch-specific opcode should be
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// at offset A_ARCHSPECIFIC.
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//
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// Subspaces are aligned to a power of two so opcodes can be masked
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// with AMask and used as compact array indices.
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const (
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ABase386 = (1 + iota) << 10
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ABaseARM
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ABaseAMD64
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ABasePPC64
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ABaseARM64
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ABaseMIPS64
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ABaseS390X
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AllowedOpCodes = 1 << 10 // The number of opcodes available for any given architecture.
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AMask = AllowedOpCodes - 1 // AND with this to use the opcode as an array index.
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)
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// An LSym is the sort of symbol that is written to an object file.
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type LSym struct {
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Name string
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Type SymKind
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Version int16
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Attribute
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RefIdx int // Index of this symbol in the symbol reference list.
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Args int32
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Locals int32
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Size int64
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Gotype *LSym
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Autom *Auto
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Text *Prog
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Pcln *Pcln
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P []byte
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R []Reloc
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}
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// Attribute is a set of symbol attributes.
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type Attribute int16
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const (
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AttrDuplicateOK Attribute = 1 << iota
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AttrCFunc
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AttrNoSplit
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AttrLeaf
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AttrSeenGlobl
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AttrOnList
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// MakeTypelink means that the type should have an entry in the typelink table.
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AttrMakeTypelink
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// ReflectMethod means the function may call reflect.Type.Method or
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// reflect.Type.MethodByName. Matching is imprecise (as reflect.Type
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// can be used through a custom interface), so ReflectMethod may be
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// set in some cases when the reflect package is not called.
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//
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// Used by the linker to determine what methods can be pruned.
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AttrReflectMethod
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// Local means make the symbol local even when compiling Go code to reference Go
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// symbols in other shared libraries, as in this mode symbols are global by
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// default. "local" here means in the sense of the dynamic linker, i.e. not
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// visible outside of the module (shared library or executable) that contains its
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// definition. (When not compiling to support Go shared libraries, all symbols are
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// local in this sense unless there is a cgo_export_* directive).
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AttrLocal
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)
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func (a Attribute) DuplicateOK() bool { return a&AttrDuplicateOK != 0 }
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func (a Attribute) MakeTypelink() bool { return a&AttrMakeTypelink != 0 }
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func (a Attribute) CFunc() bool { return a&AttrCFunc != 0 }
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func (a Attribute) NoSplit() bool { return a&AttrNoSplit != 0 }
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func (a Attribute) Leaf() bool { return a&AttrLeaf != 0 }
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func (a Attribute) SeenGlobl() bool { return a&AttrSeenGlobl != 0 }
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func (a Attribute) OnList() bool { return a&AttrOnList != 0 }
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func (a Attribute) ReflectMethod() bool { return a&AttrReflectMethod != 0 }
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func (a Attribute) Local() bool { return a&AttrLocal != 0 }
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func (a *Attribute) Set(flag Attribute, value bool) {
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if value {
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*a |= flag
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} else {
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*a &^= flag
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}
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}
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// The compiler needs LSym to satisfy fmt.Stringer, because it stores
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// an LSym in ssa.ExternSymbol.
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func (s *LSym) String() string {
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return s.Name
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}
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type Pcln struct {
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Pcsp Pcdata
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Pcfile Pcdata
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Pcline Pcdata
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Pcdata []Pcdata
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Funcdata []*LSym
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Funcdataoff []int64
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File []*LSym
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Lastfile *LSym
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Lastindex int
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}
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// A SymKind describes the kind of memory represented by a symbol.
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type SymKind int16
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// Defined SymKind values.
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//
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// TODO(rsc): Give idiomatic Go names.
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// TODO(rsc): Reduce the number of symbol types in the object files.
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//go:generate stringer -type=SymKind
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const (
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Sxxx SymKind = iota
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STEXT
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SELFRXSECT
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// Read-only sections.
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STYPE
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SSTRING
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SGOSTRING
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SGOFUNC
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SGCBITS
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SRODATA
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SFUNCTAB
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SELFROSECT
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SMACHOPLT
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// Read-only sections with relocations.
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//
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// Types STYPE-SFUNCTAB above are written to the .rodata section by default.
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// When linking a shared object, some conceptually "read only" types need to
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// be written to by relocations and putting them in a section called
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// ".rodata" interacts poorly with the system linkers. The GNU linkers
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// support this situation by arranging for sections of the name
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// ".data.rel.ro.XXX" to be mprotected read only by the dynamic linker after
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// relocations have applied, so when the Go linker is creating a shared
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// object it checks all objects of the above types and bumps any object that
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// has a relocation to it to the corresponding type below, which are then
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// written to sections with appropriate magic names.
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STYPERELRO
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SSTRINGRELRO
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SGOSTRINGRELRO
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|
SGOFUNCRELRO
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SGCBITSRELRO
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|
SRODATARELRO
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|
SFUNCTABRELRO
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|
|
|
// Part of .data.rel.ro if it exists, otherwise part of .rodata.
|
|
STYPELINK
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SITABLINK
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|
SSYMTAB
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|
SPCLNTAB
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|
|
|
// Writable sections.
|
|
SELFSECT
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|
SMACHO
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|
SMACHOGOT
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|
SWINDOWS
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|
SELFGOT
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|
SNOPTRDATA
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|
SINITARR
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|
SDATA
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|
SBSS
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|
SNOPTRBSS
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|
STLSBSS
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|
SXREF
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|
SMACHOSYMSTR
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|
SMACHOSYMTAB
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|
SMACHOINDIRECTPLT
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|
SMACHOINDIRECTGOT
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|
SFILE
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|
SFILEPATH
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|
SCONST
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|
SDYNIMPORT
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|
SHOSTOBJ
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|
SDWARFSECT
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|
SDWARFINFO
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|
SSUB = SymKind(1 << 8)
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SMASK = SymKind(SSUB - 1)
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|
SHIDDEN = SymKind(1 << 9)
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|
SCONTAINER = SymKind(1 << 10) // has a sub-symbol
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)
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|
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|
// ReadOnly are the symbol kinds that form read-only sections. In some
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// cases, if they will require relocations, they are transformed into
|
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// rel-ro sections using RelROMap.
|
|
var ReadOnly = []SymKind{
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STYPE,
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SSTRING,
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SGOSTRING,
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SGOFUNC,
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SGCBITS,
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SRODATA,
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SFUNCTAB,
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}
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|
|
|
// RelROMap describes the transformation of read-only symbols to rel-ro
|
|
// symbols.
|
|
var RelROMap = map[SymKind]SymKind{
|
|
STYPE: STYPERELRO,
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SSTRING: SSTRINGRELRO,
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SGOSTRING: SGOSTRINGRELRO,
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SGOFUNC: SGOFUNCRELRO,
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SGCBITS: SGCBITSRELRO,
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SRODATA: SRODATARELRO,
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SFUNCTAB: SFUNCTABRELRO,
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}
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|
|
|
type Reloc struct {
|
|
Off int32
|
|
Siz uint8
|
|
Type RelocType
|
|
Add int64
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|
Sym *LSym
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|
}
|
|
|
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type RelocType int32
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|
|
|
//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] }
|