func stacksplitPost(ctxt *obj.Link, p *obj.Prog, pPre *obj.Prog, pPreempt *obj.Prog) *obj.Prog {
// MOVD LR, R5
p = obj.Appendp(ctxt, p)
pPre.Pcond = p
p.As = AMOVD
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_LR
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R5
if pPreempt != nil {
pPreempt.Pcond = p
}
// BL runtime.morestack(SB)
p = obj.Appendp(ctxt, p)
p.As = ABL
p.To.Type = obj.TYPE_BRANCH
if ctxt.Cursym.Cfunc {
p.To.Sym = obj.Linklookup(ctxt, "runtime.morestackc", 0)
} else if ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0 {
p.To.Sym = obj.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
} else {
p.To.Sym = obj.Linklookup(ctxt, "runtime.morestack", 0)
}
// BR start
p = obj.Appendp(ctxt, p)
p.As = ABR
p.To.Type = obj.TYPE_BRANCH
p.Pcond = ctxt.Cursym.Text.Link
return p
}
func initdiv(ctxt *obj.Link) {
if ctxt.Sym_div != nil {
return
}
ctxt.Sym_div = obj.Linklookup(ctxt, "_div", 0)
ctxt.Sym_divu = obj.Linklookup(ctxt, "_divu", 0)
ctxt.Sym_mod = obj.Linklookup(ctxt, "_mod", 0)
ctxt.Sym_modu = obj.Linklookup(ctxt, "_modu", 0)
}
// dname creates a reflect.name for a struct field or method.
func dname(name, tag string, pkg *Pkg, exported bool) *obj.LSym {
// Write out data as "type.." to signal two things to the
// linker, first that when dynamically linking, the symbol
// should be moved to a relro section, and second that the
// contents should not be decoded as a type.
sname := "type..namedata."
if pkg == nil {
// In the common case, share data with other packages.
if name == "" {
if exported {
sname += "-noname-exported." + tag
} else {
sname += "-noname-unexported." + tag
}
} else {
sname += name + "." + tag
}
} else {
sname = fmt.Sprintf(`%s"".%d`, sname, dnameCount)
dnameCount++
}
s := obj.Linklookup(Ctxt, sname, 0)
if len(s.P) > 0 {
return s
}
ot := dnameData(s, 0, name, tag, pkg, exported)
ggloblLSym(s, int32(ot), obj.DUPOK|obj.RODATA)
return s
}
func dimportpath(p *Pkg) {
if p.Pathsym != nil {
return
}
// If we are compiling the runtime package, there are two runtime packages around
// -- localpkg and Runtimepkg. We don't want to produce import path symbols for
// both of them, so just produce one for localpkg.
if myimportpath == "runtime" && p == Runtimepkg {
return
}
var str string
if p == localpkg {
// Note: myimportpath != "", or else dgopkgpath won't call dimportpath.
str = myimportpath
} else {
str = p.Path
}
s := obj.Linklookup(Ctxt, "type..importpath."+p.Prefix+".", 0)
ot := dnameData(s, 0, str, "", nil, false)
ggloblLSym(s, int32(ot), obj.DUPOK|obj.RODATA)
p.Pathsym = s
}
func rewriteToPcrel(ctxt *obj.Link, p *obj.Prog) {
// RegTo2 is set on the instructions we insert here so they don't get
// processed twice.
if p.RegTo2 != 0 {
return
}
if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP {
return
}
// Any Prog (aside from the above special cases) with an Addr with Name ==
// NAME_EXTERN, NAME_STATIC or NAME_GOTREF has a CALL __x86.get_pc_thunk.cx
// inserted before it.
isName := func(a *obj.Addr) bool {
if a.Sym == nil || (a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR) || a.Reg != 0 {
return false
}
if a.Sym.Type == obj.STLSBSS {
return false
}
return a.Name == obj.NAME_EXTERN || a.Name == obj.NAME_STATIC || a.Name == obj.NAME_GOTREF
}
if isName(&p.From) && p.From.Type == obj.TYPE_ADDR {
// Handle things like "MOVL $sym, (SP)" or "PUSHL $sym" by rewriting
// to "MOVL $sym, CX; MOVL CX, (SP)" or "MOVL $sym, CX; PUSHL CX"
// respectively.
if p.To.Type != obj.TYPE_REG {
q := obj.Appendp(ctxt, p)
q.As = p.As
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_CX
q.To = p.To
p.As = AMOVL
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_CX
p.To.Sym = nil
p.To.Name = obj.NAME_NONE
}
}
if !isName(&p.From) && !isName(&p.To) && (p.From3 == nil || !isName(p.From3)) {
return
}
q := obj.Appendp(ctxt, p)
q.RegTo2 = 1
r := obj.Appendp(ctxt, q)
r.RegTo2 = 1
q.As = obj.ACALL
q.To.Sym = obj.Linklookup(ctxt, "__x86.get_pc_thunk.cx", 0)
q.To.Type = obj.TYPE_MEM
q.To.Name = obj.NAME_EXTERN
q.To.Sym.Local = true
r.As = p.As
r.Scond = p.Scond
r.From = p.From
r.From3 = p.From3
r.Reg = p.Reg
r.To = p.To
obj.Nopout(p)
}
// dgopkgpathOffLSym writes an offset relocation in s at offset ot to the pkg path symbol.
func dgopkgpathOffLSym(s *obj.LSym, ot int, pkg *Pkg) int {
if pkg == nil {
return duintxxLSym(s, ot, 0, 4)
}
if pkg == localpkg && myimportpath == "" {
// If we don't know the full import path of the package being compiled
// (i.e. -p was not passed on the compiler command line), emit a reference to
// type..importpath.""., which the linker will rewrite using the correct import path.
// Every package that imports this one directly defines the symbol.
// See also https://groups.google.com/forum/#!topic/golang-dev/myb9s53HxGQ.
ns := obj.Linklookup(Ctxt, `type..importpath."".`, 0)
return dsymptrOffLSym(s, ot, ns, 0)
}
dimportpath(pkg)
return dsymptrOffLSym(s, ot, pkg.Pathsym, 0)
}
func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
// MOVV g_stackguard(g), R1
p = obj.Appendp(ctxt, p)
p.As = AMOVV
p.From.Type = obj.TYPE_MEM
p.From.Reg = REGG
p.From.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
if ctxt.Cursym.Cfunc {
p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
}
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R1
var q *obj.Prog
if framesize <= obj.StackSmall {
// small stack: SP < stackguard
// AGTU SP, stackguard, R1
p = obj.Appendp(ctxt, p)
p.As = ASGTU
p.From.Type = obj.TYPE_REG
p.From.Reg = REGSP
p.Reg = REG_R1
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R1
} else if framesize <= obj.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// ADDV $-framesize, SP, R2
// SGTU R2, stackguard, R1
p = obj.Appendp(ctxt, p)
p.As = AADDV
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(-framesize)
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p = obj.Appendp(ctxt, p)
p.As = ASGTU
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R2
p.Reg = REG_R1
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R1
} else {
// Such a large stack we need to protect against wraparound.
// If SP is close to zero:
// SP-stackguard+StackGuard <= framesize + (StackGuard-StackSmall)
// The +StackGuard on both sides is required to keep the left side positive:
// SP is allowed to be slightly below stackguard. See stack.h.
//
// Preemption sets stackguard to StackPreempt, a very large value.
// That breaks the math above, so we have to check for that explicitly.
// // stackguard is R1
// MOVV $StackPreempt, R2
// BEQ R1, R2, label-of-call-to-morestack
// ADDV $StackGuard, SP, R2
// SUBVU R1, R2
// MOVV $(framesize+(StackGuard-StackSmall)), R1
// SGTU R2, R1, R1
p = obj.Appendp(ctxt, p)
p.As = AMOVV
p.From.Type = obj.TYPE_CONST
p.From.Offset = obj.StackPreempt
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p = obj.Appendp(ctxt, p)
q = p
p.As = ABEQ
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R1
p.Reg = REG_R2
p.To.Type = obj.TYPE_BRANCH
p.Mark |= BRANCH
p = obj.Appendp(ctxt, p)
p.As = AADDV
p.From.Type = obj.TYPE_CONST
p.From.Offset = obj.StackGuard
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p = obj.Appendp(ctxt, p)
p.As = ASUBVU
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R1
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p = obj.Appendp(ctxt, p)
p.As = AMOVV
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(framesize) + obj.StackGuard - obj.StackSmall
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R1
p = obj.Appendp(ctxt, p)
p.As = ASGTU
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R2
p.Reg = REG_R1
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R1
}
// q1: BNE R1, done
p = obj.Appendp(ctxt, p)
q1 := p
p.As = ABNE
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R1
p.To.Type = obj.TYPE_BRANCH
p.Mark |= BRANCH
// MOVV LINK, R3
p = obj.Appendp(ctxt, p)
p.As = AMOVV
p.From.Type = obj.TYPE_REG
p.From.Reg = REGLINK
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R3
if q != nil {
q.Pcond = p
p.Mark |= LABEL
}
// JAL runtime.morestack(SB)
p = obj.Appendp(ctxt, p)
p.As = AJAL
p.To.Type = obj.TYPE_BRANCH
if ctxt.Cursym.Cfunc {
p.To.Sym = obj.Linklookup(ctxt, "runtime.morestackc", 0)
} else if ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0 {
p.To.Sym = obj.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
} else {
p.To.Sym = obj.Linklookup(ctxt, "runtime.morestack", 0)
}
p.Mark |= BRANCH
// JMP start
p = obj.Appendp(ctxt, p)
p.As = AJMP
p.To.Type = obj.TYPE_BRANCH
p.Pcond = ctxt.Cursym.Text.Link
p.Mark |= BRANCH
// placeholder for q1's jump target
p = obj.Appendp(ctxt, p)
p.As = obj.ANOP // zero-width place holder
q1.Pcond = p
return p
}
func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
// MOVW g_stackguard(g), R1
p = obj.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type = obj.TYPE_MEM
p.From.Reg = REGG
p.From.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
if ctxt.Cursym.Cfunc {
p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
}
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R1
if framesize <= obj.StackSmall {
// small stack: SP < stackguard
// CMP stackguard, SP
p = obj.Appendp(ctxt, p)
p.As = ACMP
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R1
p.Reg = REGSP
} else if framesize <= obj.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// MOVW $-framesize(SP), R2
// CMP stackguard, R2
p = obj.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type = obj.TYPE_ADDR
p.From.Reg = REGSP
p.From.Offset = int64(-framesize)
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p = obj.Appendp(ctxt, p)
p.As = ACMP
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R1
p.Reg = REG_R2
} else {
// Such a large stack we need to protect against wraparound
// if SP is close to zero.
// SP-stackguard+StackGuard < framesize + (StackGuard-StackSmall)
// The +StackGuard on both sides is required to keep the left side positive:
// SP is allowed to be slightly below stackguard. See stack.h.
// CMP $StackPreempt, R1
// MOVW.NE $StackGuard(SP), R2
// SUB.NE R1, R2
// MOVW.NE $(framesize+(StackGuard-StackSmall)), R3
// CMP.NE R3, R2
p = obj.Appendp(ctxt, p)
p.As = ACMP
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(uint32(obj.StackPreempt & (1<<32 - 1)))
p.Reg = REG_R1
p = obj.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type = obj.TYPE_ADDR
p.From.Reg = REGSP
p.From.Offset = obj.StackGuard
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p.Scond = C_SCOND_NE
p = obj.Appendp(ctxt, p)
p.As = ASUB
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R1
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p.Scond = C_SCOND_NE
p = obj.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type = obj.TYPE_ADDR
p.From.Offset = int64(framesize) + (obj.StackGuard - obj.StackSmall)
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R3
p.Scond = C_SCOND_NE
p = obj.Appendp(ctxt, p)
p.As = ACMP
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R3
p.Reg = REG_R2
p.Scond = C_SCOND_NE
}
// BLS call-to-morestack
bls := obj.Appendp(ctxt, p)
bls.As = ABLS
bls.To.Type = obj.TYPE_BRANCH
var last *obj.Prog
for last = ctxt.Cursym.Text; last.Link != nil; last = last.Link {
}
spfix := obj.Appendp(ctxt, last)
spfix.As = obj.ANOP
spfix.Spadj = -framesize
// MOVW LR, R3
movw := obj.Appendp(ctxt, spfix)
movw.As = AMOVW
movw.From.Type = obj.TYPE_REG
movw.From.Reg = REGLINK
movw.To.Type = obj.TYPE_REG
movw.To.Reg = REG_R3
bls.Pcond = movw
// BL runtime.morestack
call := obj.Appendp(ctxt, movw)
call.As = obj.ACALL
call.To.Type = obj.TYPE_BRANCH
morestack := "runtime.morestack"
switch {
case ctxt.Cursym.Cfunc:
morestack = "runtime.morestackc"
case ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0:
morestack = "runtime.morestack_noctxt"
}
call.To.Sym = obj.Linklookup(ctxt, morestack, 0)
// B start
b := obj.Appendp(ctxt, call)
b.As = obj.AJMP
b.To.Type = obj.TYPE_BRANCH
b.Pcond = ctxt.Cursym.Text.Link
b.Spadj = +framesize
return bls
}
func progedit(ctxt *obj.Link, p *obj.Prog) {
p.From.Class = 0
p.To.Class = 0
// Rewrite B/BL to symbol as TYPE_BRANCH.
switch p.As {
case AB,
ABL,
obj.ADUFFZERO,
obj.ADUFFCOPY:
if p.To.Type == obj.TYPE_MEM && (p.To.Name == obj.NAME_EXTERN || p.To.Name == obj.NAME_STATIC) && p.To.Sym != nil {
p.To.Type = obj.TYPE_BRANCH
}
}
// Replace TLS register fetches on older ARM processors.
switch p.As {
// Treat MRC 15, 0, <reg>, C13, C0, 3 specially.
case AMRC:
if p.To.Offset&0xffff0fff == 0xee1d0f70 {
// Because the instruction might be rewritten to a BL which returns in R0
// the register must be zero.
if p.To.Offset&0xf000 != 0 {
ctxt.Diag("%v: TLS MRC instruction must write to R0 as it might get translated into a BL instruction", p.Line())
}
if ctxt.Goarm < 7 {
// Replace it with BL runtime.read_tls_fallback(SB) for ARM CPUs that lack the tls extension.
if progedit_tlsfallback == nil {
progedit_tlsfallback = obj.Linklookup(ctxt, "runtime.read_tls_fallback", 0)
}
// MOVW LR, R11
p.As = AMOVW
p.From.Type = obj.TYPE_REG
p.From.Reg = REGLINK
p.To.Type = obj.TYPE_REG
p.To.Reg = REGTMP
// BL runtime.read_tls_fallback(SB)
p = obj.Appendp(ctxt, p)
p.As = ABL
p.To.Type = obj.TYPE_BRANCH
p.To.Sym = progedit_tlsfallback
p.To.Offset = 0
// MOVW R11, LR
p = obj.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type = obj.TYPE_REG
p.From.Reg = REGTMP
p.To.Type = obj.TYPE_REG
p.To.Reg = REGLINK
break
}
}
// Otherwise, MRC/MCR instructions need no further treatment.
p.As = AWORD
}
// Rewrite float constants to values stored in memory.
switch p.As {
case AMOVF:
if p.From.Type == obj.TYPE_FCONST && chipfloat5(ctxt, p.From.Val.(float64)) < 0 && (chipzero5(ctxt, p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) {
f32 := float32(p.From.Val.(float64))
i32 := math.Float32bits(f32)
literal := fmt.Sprintf("$f32.%08x", i32)
s := obj.Linklookup(ctxt, literal, 0)
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
case AMOVD:
if p.From.Type == obj.TYPE_FCONST && chipfloat5(ctxt, p.From.Val.(float64)) < 0 && (chipzero5(ctxt, p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) {
i64 := math.Float64bits(p.From.Val.(float64))
literal := fmt.Sprintf("$f64.%016x", i64)
s := obj.Linklookup(ctxt, literal, 0)
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
}
if ctxt.Flag_dynlink {
rewriteToUseGot(ctxt, p)
}
}
func progedit(ctxt *obj.Link, p *obj.Prog) {
// Maintain information about code generation mode.
if ctxt.Mode == 0 {
ctxt.Mode = ctxt.Arch.RegSize * 8
}
p.Mode = int8(ctxt.Mode)
switch p.As {
case AMODE:
if p.From.Type == obj.TYPE_CONST || (p.From.Type == obj.TYPE_MEM && p.From.Reg == REG_NONE) {
switch int(p.From.Offset) {
case 16, 32, 64:
ctxt.Mode = int(p.From.Offset)
}
}
obj.Nopout(p)
}
// Thread-local storage references use the TLS pseudo-register.
// As a register, TLS refers to the thread-local storage base, and it
// can only be loaded into another register:
//
// MOVQ TLS, AX
//
// An offset from the thread-local storage base is written off(reg)(TLS*1).
// Semantically it is off(reg), but the (TLS*1) annotation marks this as
// indexing from the loaded TLS base. This emits a relocation so that
// if the linker needs to adjust the offset, it can. For example:
//
// MOVQ TLS, AX
// MOVQ 0(AX)(TLS*1), CX // load g into CX
//
// On systems that support direct access to the TLS memory, this
// pair of instructions can be reduced to a direct TLS memory reference:
//
// MOVQ 0(TLS), CX // load g into CX
//
// The 2-instruction and 1-instruction forms correspond to the two code
// sequences for loading a TLS variable in the local exec model given in "ELF
// Handling For Thread-Local Storage".
//
// We apply this rewrite on systems that support the 1-instruction form.
// The decision is made using only the operating system and the -shared flag,
// not the link mode. If some link modes on a particular operating system
// require the 2-instruction form, then all builds for that operating system
// will use the 2-instruction form, so that the link mode decision can be
// delayed to link time.
//
// In this way, all supported systems use identical instructions to
// access TLS, and they are rewritten appropriately first here in
// liblink and then finally using relocations in the linker.
//
// When -shared is passed, we leave the code in the 2-instruction form but
// assemble (and relocate) them in different ways to generate the initial
// exec code sequence. It's a bit of a fluke that this is possible without
// rewriting the instructions more comprehensively, and it only does because
// we only support a single TLS variable (g).
if CanUse1InsnTLS(ctxt) {
// Reduce 2-instruction sequence to 1-instruction sequence.
// Sequences like
// MOVQ TLS, BX
// ... off(BX)(TLS*1) ...
// become
// NOP
// ... off(TLS) ...
//
// TODO(rsc): Remove the Hsolaris special case. It exists only to
// guarantee we are producing byte-identical binaries as before this code.
// But it should be unnecessary.
if (p.As == AMOVQ || p.As == AMOVL) && p.From.Type == obj.TYPE_REG && p.From.Reg == REG_TLS && p.To.Type == obj.TYPE_REG && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 && ctxt.Headtype != obj.Hsolaris {
obj.Nopout(p)
}
if p.From.Type == obj.TYPE_MEM && p.From.Index == REG_TLS && REG_AX <= p.From.Reg && p.From.Reg <= REG_R15 {
p.From.Reg = REG_TLS
p.From.Scale = 0
p.From.Index = REG_NONE
}
if p.To.Type == obj.TYPE_MEM && p.To.Index == REG_TLS && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 {
p.To.Reg = REG_TLS
p.To.Scale = 0
p.To.Index = REG_NONE
}
} else {
// load_g_cx, below, always inserts the 1-instruction sequence. Rewrite it
// as the 2-instruction sequence if necessary.
// MOVQ 0(TLS), BX
// becomes
// MOVQ TLS, BX
// MOVQ 0(BX)(TLS*1), BX
if (p.As == AMOVQ || p.As == AMOVL) && p.From.Type == obj.TYPE_MEM && p.From.Reg == REG_TLS && p.To.Type == obj.TYPE_REG && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 {
q := obj.Appendp(ctxt, p)
q.As = p.As
q.From = p.From
q.From.Type = obj.TYPE_MEM
q.From.Reg = p.To.Reg
q.From.Index = REG_TLS
q.From.Scale = 2 // TODO: use 1
q.To = p.To
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_TLS
p.From.Index = REG_NONE
p.From.Offset = 0
}
}
// TODO: Remove.
if ctxt.Headtype == obj.Hwindows && p.Mode == 64 || ctxt.Headtype == obj.Hplan9 {
if p.From.Scale == 1 && p.From.Index == REG_TLS {
p.From.Scale = 2
}
if p.To.Scale == 1 && p.To.Index == REG_TLS {
p.To.Scale = 2
}
}
// Rewrite 0 to $0 in 3rd argument to CMPPS etc.
// That's what the tables expect.
switch p.As {
case ACMPPD, ACMPPS, ACMPSD, ACMPSS:
if p.To.Type == obj.TYPE_MEM && p.To.Name == obj.NAME_NONE && p.To.Reg == REG_NONE && p.To.Index == REG_NONE && p.To.Sym == nil {
p.To.Type = obj.TYPE_CONST
}
}
// Rewrite CALL/JMP/RET to symbol as TYPE_BRANCH.
switch p.As {
case obj.ACALL, obj.AJMP, obj.ARET:
if p.To.Type == obj.TYPE_MEM && (p.To.Name == obj.NAME_EXTERN || p.To.Name == obj.NAME_STATIC) && p.To.Sym != nil {
p.To.Type = obj.TYPE_BRANCH
}
}
// Rewrite MOVL/MOVQ $XXX(FP/SP) as LEAL/LEAQ.
if p.From.Type == obj.TYPE_ADDR && (ctxt.Arch.Family == sys.AMD64 || p.From.Name != obj.NAME_EXTERN && p.From.Name != obj.NAME_STATIC) {
switch p.As {
case AMOVL:
p.As = ALEAL
p.From.Type = obj.TYPE_MEM
case AMOVQ:
p.As = ALEAQ
p.From.Type = obj.TYPE_MEM
}
}
if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
if p.From3 != nil {
nacladdr(ctxt, p, p.From3)
}
nacladdr(ctxt, p, &p.From)
nacladdr(ctxt, p, &p.To)
}
// Rewrite float constants to values stored in memory.
switch p.As {
// Convert AMOVSS $(0), Xx to AXORPS Xx, Xx
case AMOVSS:
if p.From.Type == obj.TYPE_FCONST {
// f == 0 can't be used here due to -0, so use Float64bits
if f := p.From.Val.(float64); math.Float64bits(f) == 0 {
if p.To.Type == obj.TYPE_REG && REG_X0 <= p.To.Reg && p.To.Reg <= REG_X15 {
p.As = AXORPS
p.From = p.To
break
}
}
}
fallthrough
case AFMOVF,
AFADDF,
AFSUBF,
AFSUBRF,
AFMULF,
AFDIVF,
AFDIVRF,
AFCOMF,
AFCOMFP,
AADDSS,
ASUBSS,
AMULSS,
ADIVSS,
ACOMISS,
AUCOMISS:
if p.From.Type == obj.TYPE_FCONST {
f32 := float32(p.From.Val.(float64))
i32 := math.Float32bits(f32)
literal := fmt.Sprintf("$f32.%08x", i32)
s := obj.Linklookup(ctxt, literal, 0)
p.From.Type = obj.TYPE_MEM
p.From.Name = obj.NAME_EXTERN
p.From.Sym = s
p.From.Sym.Local = true
p.From.Offset = 0
}
case AMOVSD:
// Convert AMOVSD $(0), Xx to AXORPS Xx, Xx
if p.From.Type == obj.TYPE_FCONST {
// f == 0 can't be used here due to -0, so use Float64bits
if f := p.From.Val.(float64); math.Float64bits(f) == 0 {
if p.To.Type == obj.TYPE_REG && REG_X0 <= p.To.Reg && p.To.Reg <= REG_X15 {
p.As = AXORPS
p.From = p.To
break
}
}
}
fallthrough
case AFMOVD,
AFADDD,
AFSUBD,
AFSUBRD,
AFMULD,
AFDIVD,
AFDIVRD,
AFCOMD,
AFCOMDP,
AADDSD,
ASUBSD,
AMULSD,
ADIVSD,
ACOMISD,
AUCOMISD:
if p.From.Type == obj.TYPE_FCONST {
i64 := math.Float64bits(p.From.Val.(float64))
literal := fmt.Sprintf("$f64.%016x", i64)
s := obj.Linklookup(ctxt, literal, 0)
p.From.Type = obj.TYPE_MEM
p.From.Name = obj.NAME_EXTERN
p.From.Sym = s
p.From.Sym.Local = true
p.From.Offset = 0
}
}
if ctxt.Flag_dynlink {
rewriteToUseGot(ctxt, p)
}
if ctxt.Flag_shared && p.Mode == 32 {
rewriteToPcrel(ctxt, p)
}
}
func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
if ctxt.Headtype == obj.Hplan9 && ctxt.Plan9privates == nil {
ctxt.Plan9privates = obj.Linklookup(ctxt, "_privates", 0)
}
ctxt.Cursym = cursym
if cursym.Text == nil || cursym.Text.Link == nil {
return
}
p := cursym.Text
autoffset := int32(p.To.Offset)
if autoffset < 0 {
autoffset = 0
}
var bpsize int
if p.Mode == 64 && ctxt.Framepointer_enabled && autoffset > 0 && p.From3.Offset&obj.NOFRAME == 0 {
// Make room for to save a base pointer. If autoffset == 0,
// this might do something special like a tail jump to
// another function, so in that case we omit this.
bpsize = ctxt.Arch.PtrSize
autoffset += int32(bpsize)
p.To.Offset += int64(bpsize)
} else {
bpsize = 0
}
textarg := int64(p.To.Val.(int32))
cursym.Args = int32(textarg)
cursym.Locals = int32(p.To.Offset)
// TODO(rsc): Remove.
if p.Mode == 32 && cursym.Locals < 0 {
cursym.Locals = 0
}
// TODO(rsc): Remove 'p.Mode == 64 &&'.
if p.Mode == 64 && autoffset < obj.StackSmall && p.From3Offset()&obj.NOSPLIT == 0 {
for q := p; q != nil; q = q.Link {
if q.As == obj.ACALL {
goto noleaf
}
if (q.As == obj.ADUFFCOPY || q.As == obj.ADUFFZERO) && autoffset >= obj.StackSmall-8 {
goto noleaf
}
}
p.From3.Offset |= obj.NOSPLIT
noleaf:
}
if p.From3Offset()&obj.NOSPLIT == 0 || p.From3Offset()&obj.WRAPPER != 0 {
p = obj.Appendp(ctxt, p)
p = load_g_cx(ctxt, p) // load g into CX
}
if cursym.Text.From3Offset()&obj.NOSPLIT == 0 {
p = stacksplit(ctxt, p, autoffset, int32(textarg)) // emit split check
}
if autoffset != 0 {
if autoffset%int32(ctxt.Arch.RegSize) != 0 {
ctxt.Diag("unaligned stack size %d", autoffset)
}
p = obj.Appendp(ctxt, p)
p.As = AADJSP
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(autoffset)
p.Spadj = autoffset
} else {
// zero-byte stack adjustment.
// Insert a fake non-zero adjustment so that stkcheck can
// recognize the end of the stack-splitting prolog.
p = obj.Appendp(ctxt, p)
p.As = obj.ANOP
p.Spadj = int32(-ctxt.Arch.PtrSize)
p = obj.Appendp(ctxt, p)
p.As = obj.ANOP
p.Spadj = int32(ctxt.Arch.PtrSize)
}
deltasp := autoffset
if bpsize > 0 {
// Save caller's BP
p = obj.Appendp(ctxt, p)
p.As = AMOVQ
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_BP
p.To.Type = obj.TYPE_MEM
p.To.Reg = REG_SP
p.To.Scale = 1
p.To.Offset = int64(autoffset) - int64(bpsize)
// Move current frame to BP
p = obj.Appendp(ctxt, p)
p.As = ALEAQ
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_SP
p.From.Scale = 1
p.From.Offset = int64(autoffset) - int64(bpsize)
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_BP
}
if cursym.Text.From3Offset()&obj.WRAPPER != 0 {
// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
//
// MOVQ g_panic(CX), BX
// TESTQ BX, BX
// JEQ end
// LEAQ (autoffset+8)(SP), DI
// CMPQ panic_argp(BX), DI
// JNE end
// MOVQ SP, panic_argp(BX)
// end:
// NOP
//
// The NOP is needed to give the jumps somewhere to land.
// It is a liblink NOP, not an x86 NOP: it encodes to 0 instruction bytes.
p = obj.Appendp(ctxt, p)
p.As = AMOVQ
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_CX
p.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_BX
if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
p.As = AMOVL
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_R15
p.From.Scale = 1
p.From.Index = REG_CX
}
if p.Mode == 32 {
p.As = AMOVL
}
p = obj.Appendp(ctxt, p)
p.As = ATESTQ
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_BX
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_BX
if ctxt.Headtype == obj.Hnacl || p.Mode == 32 {
p.As = ATESTL
}
p = obj.Appendp(ctxt, p)
p.As = AJEQ
p.To.Type = obj.TYPE_BRANCH
p1 := p
p = obj.Appendp(ctxt, p)
p.As = ALEAQ
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_SP
p.From.Offset = int64(autoffset) + int64(ctxt.Arch.RegSize)
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_DI
if ctxt.Headtype == obj.Hnacl || p.Mode == 32 {
p.As = ALEAL
}
p = obj.Appendp(ctxt, p)
p.As = ACMPQ
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_BX
p.From.Offset = 0 // Panic.argp
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_DI
if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
p.As = ACMPL
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_R15
p.From.Scale = 1
p.From.Index = REG_BX
}
if p.Mode == 32 {
p.As = ACMPL
}
p = obj.Appendp(ctxt, p)
p.As = AJNE
p.To.Type = obj.TYPE_BRANCH
p2 := p
p = obj.Appendp(ctxt, p)
p.As = AMOVQ
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_SP
p.To.Type = obj.TYPE_MEM
p.To.Reg = REG_BX
p.To.Offset = 0 // Panic.argp
if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
p.As = AMOVL
p.To.Type = obj.TYPE_MEM
p.To.Reg = REG_R15
p.To.Scale = 1
p.To.Index = REG_BX
}
if p.Mode == 32 {
p.As = AMOVL
}
p = obj.Appendp(ctxt, p)
p.As = obj.ANOP
p1.Pcond = p
p2.Pcond = p
}
var a int
var pcsize int
for ; p != nil; p = p.Link {
pcsize = int(p.Mode) / 8
a = int(p.From.Name)
if a == obj.NAME_AUTO {
p.From.Offset += int64(deltasp) - int64(bpsize)
}
if a == obj.NAME_PARAM {
p.From.Offset += int64(deltasp) + int64(pcsize)
}
if p.From3 != nil {
a = int(p.From3.Name)
if a == obj.NAME_AUTO {
p.From3.Offset += int64(deltasp) - int64(bpsize)
}
if a == obj.NAME_PARAM {
p.From3.Offset += int64(deltasp) + int64(pcsize)
}
}
a = int(p.To.Name)
if a == obj.NAME_AUTO {
p.To.Offset += int64(deltasp) - int64(bpsize)
}
if a == obj.NAME_PARAM {
p.To.Offset += int64(deltasp) + int64(pcsize)
}
switch p.As {
default:
continue
case APUSHL, APUSHFL:
deltasp += 4
p.Spadj = 4
continue
case APUSHQ, APUSHFQ:
deltasp += 8
p.Spadj = 8
continue
case APUSHW, APUSHFW:
deltasp += 2
p.Spadj = 2
continue
case APOPL, APOPFL:
deltasp -= 4
p.Spadj = -4
continue
case APOPQ, APOPFQ:
deltasp -= 8
p.Spadj = -8
continue
case APOPW, APOPFW:
deltasp -= 2
p.Spadj = -2
continue
case obj.ARET:
break
}
if autoffset != deltasp {
ctxt.Diag("unbalanced PUSH/POP")
}
if autoffset != 0 {
if bpsize > 0 {
// Restore caller's BP
p.As = AMOVQ
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_SP
p.From.Scale = 1
p.From.Offset = int64(autoffset) - int64(bpsize)
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_BP
p = obj.Appendp(ctxt, p)
}
p.As = AADJSP
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(-autoffset)
p.Spadj = -autoffset
p = obj.Appendp(ctxt, p)
p.As = obj.ARET
// If there are instructions following
// this ARET, they come from a branch
// with the same stackframe, so undo
// the cleanup.
p.Spadj = +autoffset
}
if p.To.Sym != nil { // retjmp
p.As = obj.AJMP
}
}
}
func indir_cx(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) {
if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
a.Type = obj.TYPE_MEM
a.Reg = REG_R15
a.Index = REG_CX
a.Scale = 1
return
}
a.Type = obj.TYPE_MEM
a.Reg = REG_CX
}
// Append code to p to load g into cx.
// Overwrites p with the first instruction (no first appendp).
// Overwriting p is unusual but it lets use this in both the
// prologue (caller must call appendp first) and in the epilogue.
// Returns last new instruction.
func load_g_cx(ctxt *obj.Link, p *obj.Prog) *obj.Prog {
p.As = AMOVQ
if ctxt.Arch.PtrSize == 4 {
p.As = AMOVL
}
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_TLS
p.From.Offset = 0
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_CX
next := p.Link
progedit(ctxt, p)
for p.Link != next {
p = p.Link
}
if p.From.Index == REG_TLS {
p.From.Scale = 2
}
return p
}
// Append code to p to check for stack split.
// Appends to (does not overwrite) p.
// Assumes g is in CX.
// Returns last new instruction.
func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32, textarg int32) *obj.Prog {
cmp := ACMPQ
lea := ALEAQ
mov := AMOVQ
sub := ASUBQ
if ctxt.Headtype == obj.Hnacl || p.Mode == 32 {
cmp = ACMPL
lea = ALEAL
mov = AMOVL
sub = ASUBL
}
var q1 *obj.Prog
if framesize <= obj.StackSmall {
// small stack: SP <= stackguard
// CMPQ SP, stackguard
p = obj.Appendp(ctxt, p)
p.As = cmp
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_SP
indir_cx(ctxt, p, &p.To)
p.To.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
if ctxt.Cursym.Cfunc {
p.To.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
}
} else if framesize <= obj.StackBig {
// large stack: SP-framesize <= stackguard-StackSmall
// LEAQ -xxx(SP), AX
// CMPQ AX, stackguard
p = obj.Appendp(ctxt, p)
p.As = lea
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_SP
p.From.Offset = -(int64(framesize) - obj.StackSmall)
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_AX
p = obj.Appendp(ctxt, p)
p.As = cmp
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_AX
indir_cx(ctxt, p, &p.To)
p.To.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
if ctxt.Cursym.Cfunc {
p.To.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
}
} else {
// Such a large stack we need to protect against wraparound.
// If SP is close to zero:
// SP-stackguard+StackGuard <= framesize + (StackGuard-StackSmall)
// The +StackGuard on both sides is required to keep the left side positive:
// SP is allowed to be slightly below stackguard. See stack.h.
//
// Preemption sets stackguard to StackPreempt, a very large value.
// That breaks the math above, so we have to check for that explicitly.
// MOVQ stackguard, CX
// CMPQ CX, $StackPreempt
// JEQ label-of-call-to-morestack
// LEAQ StackGuard(SP), AX
// SUBQ CX, AX
// CMPQ AX, $(framesize+(StackGuard-StackSmall))
p = obj.Appendp(ctxt, p)
p.As = mov
indir_cx(ctxt, p, &p.From)
p.From.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
if ctxt.Cursym.Cfunc {
p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
}
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_SI
p = obj.Appendp(ctxt, p)
p.As = cmp
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_SI
p.To.Type = obj.TYPE_CONST
p.To.Offset = obj.StackPreempt
if p.Mode == 32 {
p.To.Offset = int64(uint32(obj.StackPreempt & (1<<32 - 1)))
}
p = obj.Appendp(ctxt, p)
p.As = AJEQ
p.To.Type = obj.TYPE_BRANCH
q1 = p
p = obj.Appendp(ctxt, p)
p.As = lea
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_SP
p.From.Offset = obj.StackGuard
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_AX
p = obj.Appendp(ctxt, p)
p.As = sub
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_SI
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_AX
p = obj.Appendp(ctxt, p)
p.As = cmp
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_AX
p.To.Type = obj.TYPE_CONST
p.To.Offset = int64(framesize) + (obj.StackGuard - obj.StackSmall)
}
// common
jls := obj.Appendp(ctxt, p)
jls.As = AJLS
jls.To.Type = obj.TYPE_BRANCH
var last *obj.Prog
for last = ctxt.Cursym.Text; last.Link != nil; last = last.Link {
}
spfix := obj.Appendp(ctxt, last)
spfix.As = obj.ANOP
spfix.Spadj = -framesize
call := obj.Appendp(ctxt, spfix)
call.Lineno = ctxt.Cursym.Text.Lineno
call.Mode = ctxt.Cursym.Text.Mode
call.As = obj.ACALL
call.To.Type = obj.TYPE_BRANCH
call.To.Name = obj.NAME_EXTERN
morestack := "runtime.morestack"
switch {
case ctxt.Cursym.Cfunc:
morestack = "runtime.morestackc"
case ctxt.Cursym.Text.From3Offset()&obj.NEEDCTXT == 0:
morestack = "runtime.morestack_noctxt"
}
call.To.Sym = obj.Linklookup(ctxt, morestack, 0)
// When compiling 386 code for dynamic linking, the call needs to be adjusted
// to follow PIC rules. This in turn can insert more instructions, so we need
// to keep track of the start of the call (where the jump will be to) and the
// end (which following instructions are appended to).
callend := call
progedit(ctxt, callend)
for ; callend.Link != nil; callend = callend.Link {
progedit(ctxt, callend.Link)
}
jmp := obj.Appendp(ctxt, callend)
jmp.As = obj.AJMP
jmp.To.Type = obj.TYPE_BRANCH
jmp.Pcond = ctxt.Cursym.Text.Link
jmp.Spadj = +framesize
jls.Pcond = call
if q1 != nil {
q1.Pcond = call
}
return jls
}
func follow(ctxt *obj.Link, s *obj.LSym) {
ctxt.Cursym = s
firstp := ctxt.NewProg()
lastp := firstp
xfol(ctxt, s.Text, &lastp)
lastp.Link = nil
s.Text = firstp.Link
}
func nofollow(a obj.As) bool {
switch a {
case obj.AJMP,
obj.ARET,
AIRETL,
AIRETQ,
AIRETW,
ARETFL,
ARETFQ,
ARETFW,
obj.AUNDEF:
return true
}
return false
}
func pushpop(a obj.As) bool {
switch a {
case APUSHL,
APUSHFL,
APUSHQ,
APUSHFQ,
APUSHW,
APUSHFW,
APOPL,
APOPFL,
APOPQ,
APOPFQ,
APOPW,
APOPFW:
return true
}
return false
}
func relinv(a obj.As) obj.As {
switch a {
case AJEQ:
return AJNE
case AJNE:
return AJEQ
case AJLE:
return AJGT
case AJLS:
return AJHI
case AJLT:
return AJGE
case AJMI:
return AJPL
case AJGE:
return AJLT
case AJPL:
return AJMI
case AJGT:
return AJLE
case AJHI:
return AJLS
case AJCS:
return AJCC
case AJCC:
return AJCS
case AJPS:
return AJPC
case AJPC:
return AJPS
case AJOS:
return AJOC
case AJOC:
return AJOS
}
log.Fatalf("unknown relation: %s", obj.Aconv(a))
return 0
}
func xfol(ctxt *obj.Link, p *obj.Prog, last **obj.Prog) {
var q *obj.Prog
var i int
var a obj.As
loop:
if p == nil {
return
}
if p.As == obj.AJMP {
q = p.Pcond
if q != nil && q.As != obj.ATEXT {
/* mark instruction as done and continue layout at target of jump */
p.Mark |= DONE
p = q
if p.Mark&DONE == 0 {
goto loop
}
}
}
if p.Mark&DONE != 0 {
/*
* p goes here, but already used it elsewhere.
* copy up to 4 instructions or else branch to other copy.
*/
i = 0
q = p
for ; i < 4; i, q = i+1, q.Link {
if q == nil {
break
}
if q == *last {
break
}
a = q.As
if a == obj.ANOP {
i--
continue
}
if nofollow(a) || pushpop(a) {
break // NOTE(rsc): arm does goto copy
}
if q.Pcond == nil || q.Pcond.Mark&DONE != 0 {
continue
}
if a == obj.ACALL || a == ALOOP {
continue
}
for {
if p.As == obj.ANOP {
p = p.Link
continue
}
q = obj.Copyp(ctxt, p)
p = p.Link
q.Mark |= DONE
(*last).Link = q
*last = q
if q.As != a || q.Pcond == nil || q.Pcond.Mark&DONE != 0 {
continue
}
q.As = relinv(q.As)
p = q.Pcond
q.Pcond = q.Link
q.Link = p
xfol(ctxt, q.Link, last)
p = q.Link
if p.Mark&DONE != 0 {
return
}
goto loop
/* */
}
}
q = ctxt.NewProg()
q.As = obj.AJMP
q.Lineno = p.Lineno
q.To.Type = obj.TYPE_BRANCH
q.To.Offset = p.Pc
q.Pcond = p
p = q
}
/* emit p */
p.Mark |= DONE
(*last).Link = p
*last = p
a = p.As
/* continue loop with what comes after p */
if nofollow(a) {
return
}
if p.Pcond != nil && a != obj.ACALL {
/*
* some kind of conditional branch.
* recurse to follow one path.
* continue loop on the other.
*/
q = obj.Brchain(ctxt, p.Pcond)
if q != nil {
p.Pcond = q
}
q = obj.Brchain(ctxt, p.Link)
if q != nil {
p.Link = q
}
if p.From.Type == obj.TYPE_CONST {
if p.From.Offset == 1 {
/*
* expect conditional jump to be taken.
* rewrite so that's the fall-through case.
*/
p.As = relinv(a)
q = p.Link
p.Link = p.Pcond
p.Pcond = q
}
} else {
q = p.Link
if q.Mark&DONE != 0 {
if a != ALOOP {
p.As = relinv(a)
p.Link = p.Pcond
p.Pcond = q
}
}
}
xfol(ctxt, p.Link, last)
if p.Pcond.Mark&DONE != 0 {
return
}
p = p.Pcond
goto loop
}
p = p.Link
goto loop
}
var unaryDst = map[obj.As]bool{
ABSWAPL: true,
ABSWAPQ: true,
ACMPXCHG8B: true,
ADECB: true,
ADECL: true,
ADECQ: true,
ADECW: true,
AINCB: true,
AINCL: true,
AINCQ: true,
AINCW: true,
ANEGB: true,
ANEGL: true,
ANEGQ: true,
ANEGW: true,
ANOTB: true,
ANOTL: true,
ANOTQ: true,
ANOTW: true,
APOPL: true,
APOPQ: true,
APOPW: true,
ASETCC: true,
ASETCS: true,
ASETEQ: true,
ASETGE: true,
ASETGT: true,
ASETHI: true,
ASETLE: true,
ASETLS: true,
ASETLT: true,
ASETMI: true,
ASETNE: true,
ASETOC: true,
ASETOS: true,
ASETPC: true,
ASETPL: true,
ASETPS: true,
AFFREE: true,
AFLDENV: true,
AFSAVE: true,
AFSTCW: true,
AFSTENV: true,
AFSTSW: true,
AFXSAVE: true,
AFXSAVE64: true,
ASTMXCSR: true,
}
var Linkamd64 = obj.LinkArch{
Arch: sys.ArchAMD64,
Preprocess: preprocess,
Assemble: span6,
Follow: follow,
Progedit: progedit,
UnaryDst: unaryDst,
}
var Linkamd64p32 = obj.LinkArch{
Arch: sys.ArchAMD64P32,
Preprocess: preprocess,
Assemble: span6,
Follow: follow,
Progedit: progedit,
UnaryDst: unaryDst,
}
var Link386 = obj.LinkArch{
Arch: sys.Arch386,
Preprocess: preprocess,
Assemble: span6,
Follow: follow,
Progedit: progedit,
UnaryDst: unaryDst,
}
// Rewrite p, if necessary, to access global data via the global offset table.
func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) {
var add, lea, mov obj.As
var reg int16
if p.Mode == 64 {
add = AADDQ
lea = ALEAQ
mov = AMOVQ
reg = REG_R15
} else {
add = AADDL
lea = ALEAL
mov = AMOVL
reg = REG_CX
}
if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
// ADUFFxxx $offset
// becomes
// $MOV runtime.duffxxx@GOT, $reg
// $ADD $offset, $reg
// CALL $reg
var sym *obj.LSym
if p.As == obj.ADUFFZERO {
sym = obj.Linklookup(ctxt, "runtime.duffzero", 0)
} else {
sym = obj.Linklookup(ctxt, "runtime.duffcopy", 0)
}
offset := p.To.Offset
p.As = mov
p.From.Type = obj.TYPE_MEM
p.From.Name = obj.NAME_GOTREF
p.From.Sym = sym
p.To.Type = obj.TYPE_REG
p.To.Reg = reg
p.To.Offset = 0
p.To.Sym = nil
p1 := obj.Appendp(ctxt, p)
p1.As = add
p1.From.Type = obj.TYPE_CONST
p1.From.Offset = offset
p1.To.Type = obj.TYPE_REG
p1.To.Reg = reg
p2 := obj.Appendp(ctxt, p1)
p2.As = obj.ACALL
p2.To.Type = obj.TYPE_REG
p2.To.Reg = reg
}
// We only care about global data: NAME_EXTERN means a global
// symbol in the Go sense, and p.Sym.Local is true for a few
// internally defined symbols.
if p.As == lea && p.From.Type == obj.TYPE_MEM && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
// $LEA sym, Rx becomes $MOV $sym, Rx which will be rewritten below
p.As = mov
p.From.Type = obj.TYPE_ADDR
}
if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
// $MOV $sym, Rx becomes $MOV sym@GOT, Rx
// $MOV $sym+<off>, Rx becomes $MOV sym@GOT, Rx; $LEA <off>(Rx), Rx
// On 386 only, more complicated things like PUSHL $sym become $MOV sym@GOT, CX; PUSHL CX
cmplxdest := false
pAs := p.As
var dest obj.Addr
if p.To.Type != obj.TYPE_REG || pAs != mov {
if p.Mode == 64 {
ctxt.Diag("do not know how to handle LEA-type insn to non-register in %v with -dynlink", p)
}
cmplxdest = true
dest = p.To
p.As = mov
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_CX
p.To.Sym = nil
p.To.Name = obj.NAME_NONE
}
p.From.Type = obj.TYPE_MEM
p.From.Name = obj.NAME_GOTREF
q := p
if p.From.Offset != 0 {
q = obj.Appendp(ctxt, p)
q.As = lea
q.From.Type = obj.TYPE_MEM
q.From.Reg = p.To.Reg
q.From.Offset = p.From.Offset
q.To = p.To
p.From.Offset = 0
}
if cmplxdest {
q = obj.Appendp(ctxt, q)
q.As = pAs
q.To = dest
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_CX
}
}
if p.From3 != nil && p.From3.Name == obj.NAME_EXTERN {
ctxt.Diag("don't know how to handle %v with -dynlink", p)
}
var source *obj.Addr
// MOVx sym, Ry becomes $MOV sym@GOT, R15; MOVx (R15), Ry
// MOVx Ry, sym becomes $MOV sym@GOT, R15; MOVx Ry, (R15)
// An addition may be inserted between the two MOVs if there is an offset.
if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local {
ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -dynlink", p)
}
source = &p.From
} else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local {
source = &p.To
} else {
return
}
if p.As == obj.ACALL {
// When dynlinking on 386, almost any call might end up being a call
// to a PLT, so make sure the GOT pointer is loaded into BX.
// RegTo2 is set on the replacement call insn to stop it being
// processed when it is in turn passed to progedit.
if p.Mode == 64 || (p.To.Sym != nil && p.To.Sym.Local) || p.RegTo2 != 0 {
return
}
p1 := obj.Appendp(ctxt, p)
p2 := obj.Appendp(ctxt, p1)
p1.As = ALEAL
p1.From.Type = obj.TYPE_MEM
p1.From.Name = obj.NAME_STATIC
p1.From.Sym = obj.Linklookup(ctxt, "_GLOBAL_OFFSET_TABLE_", 0)
p1.To.Type = obj.TYPE_REG
p1.To.Reg = REG_BX
p2.As = p.As
p2.Scond = p.Scond
p2.From = p.From
p2.From3 = p.From3
p2.Reg = p.Reg
p2.To = p.To
// p.To.Type was set to TYPE_BRANCH above, but that makes checkaddr
// in ../pass.go complain, so set it back to TYPE_MEM here, until p2
// itself gets passed to progedit.
p2.To.Type = obj.TYPE_MEM
p2.RegTo2 = 1
obj.Nopout(p)
return
}
if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ARET || p.As == obj.AJMP {
return
}
if source.Type != obj.TYPE_MEM {
ctxt.Diag("don't know how to handle %v with -dynlink", p)
}
p1 := obj.Appendp(ctxt, p)
p2 := obj.Appendp(ctxt, p1)
p1.As = mov
p1.From.Type = obj.TYPE_MEM
p1.From.Sym = source.Sym
p1.From.Name = obj.NAME_GOTREF
p1.To.Type = obj.TYPE_REG
p1.To.Reg = reg
p2.As = p.As
p2.From = p.From
p2.To = p.To
if p.From.Name == obj.NAME_EXTERN {
p2.From.Reg = reg
p2.From.Name = obj.NAME_NONE
p2.From.Sym = nil
} else if p.To.Name == obj.NAME_EXTERN {
p2.To.Reg = reg
p2.To.Name = obj.NAME_NONE
p2.To.Sym = nil
} else {
return
}
obj.Nopout(p)
}
/*
// instruction scheduling
if(debug['Q'] == 0)
return;
curtext = nil;
q = nil; // p - 1
q1 = firstp; // top of block
o = 0; // count of instructions
for(p = firstp; p != nil; p = p1) {
p1 = p->link;
o++;
if(p->mark & NOSCHED){
if(q1 != p){
sched(q1, q);
}
for(; p != nil; p = p->link){
if(!(p->mark & NOSCHED))
break;
q = p;
}
p1 = p;
q1 = p;
o = 0;
continue;
}
if(p->mark & (LABEL|SYNC)) {
if(q1 != p)
sched(q1, q);
q1 = p;
o = 1;
}
if(p->mark & (BRANCH|SYNC)) {
sched(q1, p);
q1 = p1;
o = 0;
}
if(o >= NSCHED) {
sched(q1, p);
q1 = p1;
o = 0;
}
q = p;
}
*/
func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
// MOVD g_stackguard(g), R3
p = obj.Appendp(ctxt, p)
p.As = AMOVD
p.From.Type = obj.TYPE_MEM
p.From.Reg = REGG
p.From.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
if ctxt.Cursym.Cfunc {
p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
}
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R3
var q *obj.Prog
if framesize <= obj.StackSmall {
// small stack: SP < stackguard
// CMP stackguard, SP
p = obj.Appendp(ctxt, p)
p.As = ACMPU
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R3
p.To.Type = obj.TYPE_REG
p.To.Reg = REGSP
} else if framesize <= obj.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// ADD $-framesize, SP, R4
// CMP stackguard, R4
p = obj.Appendp(ctxt, p)
p.As = AADD
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(-framesize)
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R4
p = obj.Appendp(ctxt, p)
p.As = ACMPU
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R3
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R4
} else {
// Such a large stack we need to protect against wraparound.
// If SP is close to zero:
// SP-stackguard+StackGuard <= framesize + (StackGuard-StackSmall)
// The +StackGuard on both sides is required to keep the left side positive:
// SP is allowed to be slightly below stackguard. See stack.h.
//
// Preemption sets stackguard to StackPreempt, a very large value.
// That breaks the math above, so we have to check for that explicitly.
// // stackguard is R3
// CMP R3, $StackPreempt
// BEQ label-of-call-to-morestack
// ADD $StackGuard, SP, R4
// SUB R3, R4
// MOVD $(framesize+(StackGuard-StackSmall)), R31
// CMPU R31, R4
p = obj.Appendp(ctxt, p)
p.As = ACMP
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R3
p.To.Type = obj.TYPE_CONST
p.To.Offset = obj.StackPreempt
p = obj.Appendp(ctxt, p)
q = p
p.As = ABEQ
p.To.Type = obj.TYPE_BRANCH
p = obj.Appendp(ctxt, p)
p.As = AADD
p.From.Type = obj.TYPE_CONST
p.From.Offset = obj.StackGuard
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R4
p = obj.Appendp(ctxt, p)
p.As = ASUB
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R3
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R4
p = obj.Appendp(ctxt, p)
p.As = AMOVD
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(framesize) + obj.StackGuard - obj.StackSmall
p.To.Type = obj.TYPE_REG
p.To.Reg = REGTMP
p = obj.Appendp(ctxt, p)
p.As = ACMPU
p.From.Type = obj.TYPE_REG
p.From.Reg = REGTMP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R4
}
// q1: BLT done
p = obj.Appendp(ctxt, p)
q1 := p
p.As = ABLT
p.To.Type = obj.TYPE_BRANCH
// MOVD LR, R5
p = obj.Appendp(ctxt, p)
p.As = AMOVD
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_LR
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R5
if q != nil {
q.Pcond = p
}
var morestacksym *obj.LSym
if ctxt.Cursym.Cfunc {
morestacksym = obj.Linklookup(ctxt, "runtime.morestackc", 0)
} else if ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0 {
morestacksym = obj.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
} else {
morestacksym = obj.Linklookup(ctxt, "runtime.morestack", 0)
}
if ctxt.Flag_dynlink {
// Avoid calling morestack via a PLT when dynamically linking. The
// PLT stubs generated by the system linker on ppc64le when "std r2,
// 24(r1)" to save the TOC pointer in their callers stack
// frame. Unfortunately (and necessarily) morestack is called before
// the function that calls it sets up its frame and so the PLT ends
// up smashing the saved TOC pointer for its caller's caller.
//
// According to the ABI documentation there is a mechanism to avoid
// the TOC save that the PLT stub does (put a R_PPC64_TOCSAVE
// relocation on the nop after the call to morestack) but at the time
// of writing it is not supported at all by gold and my attempt to
// use it with ld.bfd caused an internal linker error. So this hack
// seems preferable.
// MOVD $runtime.morestack(SB), R12
p = obj.Appendp(ctxt, p)
p.As = AMOVD
p.From.Type = obj.TYPE_MEM
p.From.Sym = morestacksym
p.From.Name = obj.NAME_GOTREF
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R12
// MOVD R12, CTR
p = obj.Appendp(ctxt, p)
p.As = AMOVD
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R12
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_CTR
// BL CTR
p = obj.Appendp(ctxt, p)
p.As = obj.ACALL
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R12
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_CTR
} else {
// BL runtime.morestack(SB)
p = obj.Appendp(ctxt, p)
p.As = ABL
p.To.Type = obj.TYPE_BRANCH
p.To.Sym = morestacksym
}
// BR start
p = obj.Appendp(ctxt, p)
p.As = ABR
p.To.Type = obj.TYPE_BRANCH
p.Pcond = ctxt.Cursym.Text.Link
// placeholder for q1's jump target
p = obj.Appendp(ctxt, p)
p.As = obj.ANOP // zero-width place holder
q1.Pcond = p
return p
}
func progedit(ctxt *obj.Link, p *obj.Prog) {
p.From.Class = 0
p.To.Class = 0
// Rewrite BR/BL to symbol as TYPE_BRANCH.
switch p.As {
case ABR,
ABL,
obj.ARET,
obj.ADUFFZERO,
obj.ADUFFCOPY:
if p.To.Sym != nil {
p.To.Type = obj.TYPE_BRANCH
}
}
// Rewrite float constants to values stored in memory.
switch p.As {
case AFMOVS:
if p.From.Type == obj.TYPE_FCONST {
f32 := float32(p.From.Val.(float64))
i32 := math.Float32bits(f32)
literal := fmt.Sprintf("$f32.%08x", i32)
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 4
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Sym.Local = true
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
case AFMOVD:
if p.From.Type == obj.TYPE_FCONST {
i64 := math.Float64bits(p.From.Val.(float64))
literal := fmt.Sprintf("$f64.%016x", i64)
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 8
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Sym.Local = true
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
// Put >32-bit constants in memory and load them
case AMOVD:
if p.From.Type == obj.TYPE_CONST && p.From.Name == obj.NAME_NONE && p.From.Reg == 0 && int64(int32(p.From.Offset)) != p.From.Offset {
literal := fmt.Sprintf("$i64.%016x", uint64(p.From.Offset))
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 8
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Sym.Local = true
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
}
// Rewrite SUB constants into ADD.
switch p.As {
case ASUBC:
if p.From.Type == obj.TYPE_CONST {
p.From.Offset = -p.From.Offset
p.As = AADDC
}
case ASUBCCC:
if p.From.Type == obj.TYPE_CONST {
p.From.Offset = -p.From.Offset
p.As = AADDCCC
}
case ASUB:
if p.From.Type == obj.TYPE_CONST {
p.From.Offset = -p.From.Offset
p.As = AADD
}
}
if ctxt.Flag_dynlink {
rewriteToUseGot(ctxt, p)
}
}
func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
// TODO(minux): add morestack short-cuts with small fixed frame-size.
ctxt.Cursym = cursym
if cursym.Text == nil || cursym.Text.Link == nil {
return
}
p := cursym.Text
textstksiz := p.To.Offset
if textstksiz == -8 {
// Compatibility hack.
p.From3.Offset |= obj.NOFRAME
textstksiz = 0
}
if textstksiz%8 != 0 {
ctxt.Diag("frame size %d not a multiple of 8", textstksiz)
}
if p.From3.Offset&obj.NOFRAME != 0 {
if textstksiz != 0 {
ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz)
}
}
cursym.Args = p.To.Val.(int32)
cursym.Locals = int32(textstksiz)
/*
* find leaf subroutines
* strip NOPs
* expand RET
* expand BECOME pseudo
*/
if ctxt.Debugvlog != 0 {
fmt.Fprintf(ctxt.Bso, "%5.2f noops\n", obj.Cputime())
}
ctxt.Bso.Flush()
var q *obj.Prog
var q1 *obj.Prog
for p := cursym.Text; p != nil; p = p.Link {
switch p.As {
/* too hard, just leave alone */
case obj.ATEXT:
q = p
p.Mark |= LABEL | LEAF | SYNC
if p.Link != nil {
p.Link.Mark |= LABEL
}
case ANOR:
q = p
if p.To.Type == obj.TYPE_REG {
if p.To.Reg == REGZERO {
p.Mark |= LABEL | SYNC
}
}
case ALWAR,
ALBAR,
ASTBCCC,
ASTWCCC,
AECIWX,
AECOWX,
AEIEIO,
AICBI,
AISYNC,
ATLBIE,
ATLBIEL,
ASLBIA,
ASLBIE,
ASLBMFEE,
ASLBMFEV,
ASLBMTE,
ADCBF,
ADCBI,
ADCBST,
ADCBT,
ADCBTST,
ADCBZ,
ASYNC,
ATLBSYNC,
APTESYNC,
ALWSYNC,
ATW,
AWORD,
ARFI,
ARFCI,
ARFID,
AHRFID:
q = p
p.Mark |= LABEL | SYNC
continue
case AMOVW, AMOVWZ, AMOVD:
q = p
if p.From.Reg >= REG_SPECIAL || p.To.Reg >= REG_SPECIAL {
p.Mark |= LABEL | SYNC
}
continue
case AFABS,
AFABSCC,
AFADD,
AFADDCC,
AFCTIW,
AFCTIWCC,
AFCTIWZ,
AFCTIWZCC,
AFDIV,
AFDIVCC,
AFMADD,
AFMADDCC,
AFMOVD,
AFMOVDU,
/* case AFMOVDS: */
AFMOVS,
AFMOVSU,
/* case AFMOVSD: */
AFMSUB,
AFMSUBCC,
AFMUL,
AFMULCC,
AFNABS,
AFNABSCC,
AFNEG,
AFNEGCC,
AFNMADD,
AFNMADDCC,
AFNMSUB,
AFNMSUBCC,
AFRSP,
AFRSPCC,
AFSUB,
AFSUBCC:
q = p
p.Mark |= FLOAT
continue
case ABL,
ABCL,
obj.ADUFFZERO,
obj.ADUFFCOPY:
cursym.Text.Mark &^= LEAF
fallthrough
case ABC,
ABEQ,
ABGE,
ABGT,
ABLE,
ABLT,
ABNE,
ABR,
ABVC,
ABVS:
p.Mark |= BRANCH
q = p
q1 = p.Pcond
if q1 != nil {
for q1.As == obj.ANOP {
q1 = q1.Link
p.Pcond = q1
}
if q1.Mark&LEAF == 0 {
q1.Mark |= LABEL
}
} else {
p.Mark |= LABEL
}
q1 = p.Link
if q1 != nil {
q1.Mark |= LABEL
}
continue
case AFCMPO, AFCMPU:
q = p
p.Mark |= FCMP | FLOAT
continue
case obj.ARET:
q = p
if p.Link != nil {
p.Link.Mark |= LABEL
}
continue
case obj.ANOP:
q1 = p.Link
q.Link = q1 /* q is non-nop */
q1.Mark |= p.Mark
continue
default:
q = p
continue
}
}
autosize := int32(0)
var aoffset int
var mov obj.As
var p1 *obj.Prog
var p2 *obj.Prog
for p := cursym.Text; p != nil; p = p.Link {
o := p.As
switch o {
case obj.ATEXT:
mov = AMOVD
aoffset = 0
autosize = int32(textstksiz)
if p.Mark&LEAF != 0 && autosize == 0 && p.From3.Offset&obj.NOFRAME == 0 {
// A leaf function with no locals has no frame.
p.From3.Offset |= obj.NOFRAME
}
if p.From3.Offset&obj.NOFRAME == 0 {
// If there is a stack frame at all, it includes
// space to save the LR.
autosize += int32(ctxt.FixedFrameSize())
}
p.To.Offset = int64(autosize)
q = p
if ctxt.Flag_shared && cursym.Name != "runtime.duffzero" && cursym.Name != "runtime.duffcopy" && cursym.Name != "runtime.stackBarrier" {
// When compiling Go into PIC, all functions must start
// with instructions to load the TOC pointer into r2:
//
// addis r2, r12, .TOC.-func@ha
// addi r2, r2, .TOC.-func@l+4
//
// We could probably skip this prologue in some situations
// but it's a bit subtle. However, it is both safe and
// necessary to leave the prologue off duffzero and
// duffcopy as we rely on being able to jump to a specific
// instruction offset for them, and stackBarrier is only
// ever called from an overwritten LR-save slot on the
// stack (when r12 will not be remotely the right thing)
// but fortunately does not access global data.
//
// These are AWORDS because there is no (afaict) way to
// generate the addis instruction except as part of the
// load of a large constant, and in that case there is no
// way to use r12 as the source.
q = obj.Appendp(ctxt, q)
q.As = AWORD
q.Lineno = p.Lineno
q.From.Type = obj.TYPE_CONST
q.From.Offset = 0x3c4c0000
q = obj.Appendp(ctxt, q)
q.As = AWORD
q.Lineno = p.Lineno
q.From.Type = obj.TYPE_CONST
q.From.Offset = 0x38420000
rel := obj.Addrel(ctxt.Cursym)
rel.Off = 0
rel.Siz = 8
rel.Sym = obj.Linklookup(ctxt, ".TOC.", 0)
rel.Type = obj.R_ADDRPOWER_PCREL
}
if cursym.Text.From3.Offset&obj.NOSPLIT == 0 {
q = stacksplit(ctxt, q, autosize) // emit split check
}
if autosize != 0 {
/* use MOVDU to adjust R1 when saving R31, if autosize is small */
if cursym.Text.Mark&LEAF == 0 && autosize >= -BIG && autosize <= BIG {
mov = AMOVDU
aoffset = int(-autosize)
} else {
q = obj.Appendp(ctxt, q)
q.As = AADD
q.Lineno = p.Lineno
q.From.Type = obj.TYPE_CONST
q.From.Offset = int64(-autosize)
q.To.Type = obj.TYPE_REG
q.To.Reg = REGSP
q.Spadj = +autosize
}
} else if cursym.Text.Mark&LEAF == 0 {
// A very few functions that do not return to their caller
// (e.g. gogo) are not identified as leaves but still have
// no frame.
cursym.Text.Mark |= LEAF
}
if cursym.Text.Mark&LEAF != 0 {
cursym.Leaf = true
break
}
q = obj.Appendp(ctxt, q)
q.As = AMOVD
q.Lineno = p.Lineno
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_LR
q.To.Type = obj.TYPE_REG
q.To.Reg = REGTMP
q = obj.Appendp(ctxt, q)
q.As = mov
q.Lineno = p.Lineno
q.From.Type = obj.TYPE_REG
q.From.Reg = REGTMP
q.To.Type = obj.TYPE_MEM
q.To.Offset = int64(aoffset)
q.To.Reg = REGSP
if q.As == AMOVDU {
q.Spadj = int32(-aoffset)
}
if ctxt.Flag_shared {
q = obj.Appendp(ctxt, q)
q.As = AMOVD
q.Lineno = p.Lineno
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_R2
q.To.Type = obj.TYPE_MEM
q.To.Reg = REGSP
q.To.Offset = 24
}
if cursym.Text.From3.Offset&obj.WRAPPER != 0 {
// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
//
// MOVD g_panic(g), R3
// CMP R0, R3
// BEQ end
// MOVD panic_argp(R3), R4
// ADD $(autosize+8), R1, R5
// CMP R4, R5
// BNE end
// ADD $8, R1, R6
// MOVD R6, panic_argp(R3)
// end:
// NOP
//
// The NOP is needed to give the jumps somewhere to land.
// It is a liblink NOP, not a ppc64 NOP: it encodes to 0 instruction bytes.
q = obj.Appendp(ctxt, q)
q.As = AMOVD
q.From.Type = obj.TYPE_MEM
q.From.Reg = REGG
q.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R3
q = obj.Appendp(ctxt, q)
q.As = ACMP
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_R0
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R3
q = obj.Appendp(ctxt, q)
q.As = ABEQ
q.To.Type = obj.TYPE_BRANCH
p1 = q
q = obj.Appendp(ctxt, q)
q.As = AMOVD
q.From.Type = obj.TYPE_MEM
q.From.Reg = REG_R3
q.From.Offset = 0 // Panic.argp
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R4
q = obj.Appendp(ctxt, q)
q.As = AADD
q.From.Type = obj.TYPE_CONST
q.From.Offset = int64(autosize) + ctxt.FixedFrameSize()
q.Reg = REGSP
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R5
q = obj.Appendp(ctxt, q)
q.As = ACMP
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_R4
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R5
q = obj.Appendp(ctxt, q)
q.As = ABNE
q.To.Type = obj.TYPE_BRANCH
p2 = q
q = obj.Appendp(ctxt, q)
q.As = AADD
q.From.Type = obj.TYPE_CONST
q.From.Offset = ctxt.FixedFrameSize()
q.Reg = REGSP
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R6
q = obj.Appendp(ctxt, q)
q.As = AMOVD
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_R6
q.To.Type = obj.TYPE_MEM
q.To.Reg = REG_R3
q.To.Offset = 0 // Panic.argp
q = obj.Appendp(ctxt, q)
q.As = obj.ANOP
p1.Pcond = q
p2.Pcond = q
}
case obj.ARET:
if p.From.Type == obj.TYPE_CONST {
ctxt.Diag("using BECOME (%v) is not supported!", p)
break
}
retTarget := p.To.Sym
if cursym.Text.Mark&LEAF != 0 {
if autosize == 0 {
p.As = ABR
p.From = obj.Addr{}
if retTarget == nil {
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_LR
} else {
p.To.Type = obj.TYPE_BRANCH
p.To.Sym = retTarget
}
p.Mark |= BRANCH
break
}
p.As = AADD
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(autosize)
p.To.Type = obj.TYPE_REG
p.To.Reg = REGSP
p.Spadj = -autosize
q = ctxt.NewProg()
q.As = ABR
q.Lineno = p.Lineno
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_LR
q.Mark |= BRANCH
q.Spadj = +autosize
q.Link = p.Link
p.Link = q
break
}
p.As = AMOVD
p.From.Type = obj.TYPE_MEM
p.From.Offset = 0
p.From.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REGTMP
q = ctxt.NewProg()
q.As = AMOVD
q.Lineno = p.Lineno
q.From.Type = obj.TYPE_REG
q.From.Reg = REGTMP
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_LR
q.Link = p.Link
p.Link = q
p = q
if false {
// Debug bad returns
q = ctxt.NewProg()
q.As = AMOVD
q.Lineno = p.Lineno
q.From.Type = obj.TYPE_MEM
q.From.Offset = 0
q.From.Reg = REGTMP
q.To.Type = obj.TYPE_REG
q.To.Reg = REGTMP
q.Link = p.Link
p.Link = q
p = q
}
if autosize != 0 {
q = ctxt.NewProg()
q.As = AADD
q.Lineno = p.Lineno
q.From.Type = obj.TYPE_CONST
q.From.Offset = int64(autosize)
q.To.Type = obj.TYPE_REG
q.To.Reg = REGSP
q.Spadj = -autosize
q.Link = p.Link
p.Link = q
}
q1 = ctxt.NewProg()
q1.As = ABR
q1.Lineno = p.Lineno
if retTarget == nil {
q1.To.Type = obj.TYPE_REG
q1.To.Reg = REG_LR
} else {
q1.To.Type = obj.TYPE_BRANCH
q1.To.Sym = retTarget
}
q1.Mark |= BRANCH
q1.Spadj = +autosize
q1.Link = q.Link
q.Link = q1
case AADD:
if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST {
p.Spadj = int32(-p.From.Offset)
}
}
}
}
func typelinkLSym(t *Type) *obj.LSym {
name := "go.typelink." + Tconv(t, FmtLeft) // complete, unambiguous type name
return obj.Linklookup(Ctxt, name, 0)
}
// Rewrite p, if necessary, to access global data via the global offset table.
func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) {
if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
// ADUFFxxx $offset
// becomes
// MOVW runtime.duffxxx@GOT, R9
// ADD $offset, R9
// CALL (R9)
var sym *obj.LSym
if p.As == obj.ADUFFZERO {
sym = obj.Linklookup(ctxt, "runtime.duffzero", 0)
} else {
sym = obj.Linklookup(ctxt, "runtime.duffcopy", 0)
}
offset := p.To.Offset
p.As = AMOVW
p.From.Type = obj.TYPE_MEM
p.From.Name = obj.NAME_GOTREF
p.From.Sym = sym
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R9
p.To.Name = obj.NAME_NONE
p.To.Offset = 0
p.To.Sym = nil
p1 := obj.Appendp(ctxt, p)
p1.As = AADD
p1.From.Type = obj.TYPE_CONST
p1.From.Offset = offset
p1.To.Type = obj.TYPE_REG
p1.To.Reg = REG_R9
p2 := obj.Appendp(ctxt, p1)
p2.As = obj.ACALL
p2.To.Type = obj.TYPE_MEM
p2.To.Reg = REG_R9
return
}
// We only care about global data: NAME_EXTERN means a global
// symbol in the Go sense, and p.Sym.Local is true for a few
// internally defined symbols.
if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
// MOVW $sym, Rx becomes MOVW sym@GOT, Rx
// MOVW $sym+<off>, Rx becomes MOVW sym@GOT, Rx; ADD <off>, Rx
if p.As != AMOVW {
ctxt.Diag("do not know how to handle TYPE_ADDR in %v with -dynlink", p)
}
if p.To.Type != obj.TYPE_REG {
ctxt.Diag("do not know how to handle LEAQ-type insn to non-register in %v with -dynlink", p)
}
p.From.Type = obj.TYPE_MEM
p.From.Name = obj.NAME_GOTREF
if p.From.Offset != 0 {
q := obj.Appendp(ctxt, p)
q.As = AADD
q.From.Type = obj.TYPE_CONST
q.From.Offset = p.From.Offset
q.To = p.To
p.From.Offset = 0
}
}
if p.From3 != nil && p.From3.Name == obj.NAME_EXTERN {
ctxt.Diag("don't know how to handle %v with -dynlink", p)
}
var source *obj.Addr
// MOVx sym, Ry becomes MOVW sym@GOT, R9; MOVx (R9), Ry
// MOVx Ry, sym becomes MOVW sym@GOT, R9; MOVx Ry, (R9)
// An addition may be inserted between the two MOVs if there is an offset.
if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local {
ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -dynlink", p)
}
source = &p.From
} else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local {
source = &p.To
} else {
return
}
if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP {
return
}
if source.Sym.Type == obj.STLSBSS {
return
}
if source.Type != obj.TYPE_MEM {
ctxt.Diag("don't know how to handle %v with -dynlink", p)
}
p1 := obj.Appendp(ctxt, p)
p2 := obj.Appendp(ctxt, p1)
p1.As = AMOVW
p1.From.Type = obj.TYPE_MEM
p1.From.Sym = source.Sym
p1.From.Name = obj.NAME_GOTREF
p1.To.Type = obj.TYPE_REG
p1.To.Reg = REG_R9
p2.As = p.As
p2.From = p.From
p2.To = p.To
if p.From.Name == obj.NAME_EXTERN {
p2.From.Reg = REG_R9
p2.From.Name = obj.NAME_NONE
p2.From.Sym = nil
} else if p.To.Name == obj.NAME_EXTERN {
p2.To.Reg = REG_R9
p2.To.Name = obj.NAME_NONE
p2.To.Sym = nil
} else {
return
}
obj.Nopout(p)
}
func progedit(ctxt *obj.Link, p *obj.Prog) {
p.From.Class = 0
p.To.Class = 0
// $0 results in C_ZCON, which matches both C_REG and various
// C_xCON, however the C_REG cases in asmout don't expect a
// constant, so they will use the register fields and assemble
// a R0. To prevent that, rewrite $0 as ZR.
if p.From.Type == obj.TYPE_CONST && p.From.Offset == 0 {
p.From.Type = obj.TYPE_REG
p.From.Reg = REGZERO
}
if p.To.Type == obj.TYPE_CONST && p.To.Offset == 0 {
p.To.Type = obj.TYPE_REG
p.To.Reg = REGZERO
}
// Rewrite BR/BL to symbol as TYPE_BRANCH.
switch p.As {
case AB,
ABL,
obj.ARET,
obj.ADUFFZERO,
obj.ADUFFCOPY:
if p.To.Sym != nil {
p.To.Type = obj.TYPE_BRANCH
}
break
}
// Rewrite float constants to values stored in memory.
switch p.As {
case AFMOVS:
if p.From.Type == obj.TYPE_FCONST {
f32 := float32(p.From.Val.(float64))
i32 := math.Float32bits(f32)
literal := fmt.Sprintf("$f32.%08x", i32)
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 4
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Sym.Local = true
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
case AFMOVD:
if p.From.Type == obj.TYPE_FCONST {
i64 := math.Float64bits(p.From.Val.(float64))
literal := fmt.Sprintf("$f64.%016x", i64)
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 8
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Sym.Local = true
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
break
}
// Rewrite negative immediates as positive immediates with
// complementary instruction.
switch p.As {
case AADD,
AADDW,
ASUB,
ASUBW,
ACMP,
ACMPW,
ACMN,
ACMNW:
if p.From.Type == obj.NAME_EXTERN && p.From.Offset < 0 {
p.From.Offset = -p.From.Offset
p.As = complements[p.As]
}
break
}
if ctxt.Flag_dynlink {
rewriteToUseGot(ctxt, p)
}
}
func softfloat(ctxt *obj.Link, cursym *obj.LSym) {
if ctxt.Goarm > 5 {
return
}
symsfloat := obj.Linklookup(ctxt, "_sfloat", 0)
wasfloat := 0
for p := cursym.Text; p != nil; p = p.Link {
if p.Pcond != nil {
p.Pcond.Mark |= LABEL
}
}
var next *obj.Prog
for p := cursym.Text; p != nil; p = p.Link {
switch p.As {
case AMOVW:
if isfloatreg(&p.To) || isfloatreg(&p.From) {
goto soft
}
goto notsoft
case AMOVWD,
AMOVWF,
AMOVDW,
AMOVFW,
AMOVFD,
AMOVDF,
AMOVF,
AMOVD,
ACMPF,
ACMPD,
AADDF,
AADDD,
ASUBF,
ASUBD,
AMULF,
AMULD,
ADIVF,
ADIVD,
ASQRTF,
ASQRTD,
AABSF,
AABSD:
goto soft
default:
goto notsoft
}
soft:
if wasfloat == 0 || (p.Mark&LABEL != 0) {
next = ctxt.NewProg()
*next = *p
// BL _sfloat(SB)
*p = obj.Prog{}
p.Ctxt = ctxt
p.Link = next
p.As = ABL
p.To.Type = obj.TYPE_BRANCH
p.To.Sym = symsfloat
p.Lineno = next.Lineno
p = next
wasfloat = 1
}
continue
notsoft:
wasfloat = 0
}
}
func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
// MOV g_stackguard(g), R1
p = obj.Appendp(ctxt, p)
p.As = AMOVD
p.From.Type = obj.TYPE_MEM
p.From.Reg = REGG
p.From.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
if ctxt.Cursym.Cfunc {
p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
}
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R1
q := (*obj.Prog)(nil)
if framesize <= obj.StackSmall {
// small stack: SP < stackguard
// MOV SP, R2
// CMP stackguard, R2
p = obj.Appendp(ctxt, p)
p.As = AMOVD
p.From.Type = obj.TYPE_REG
p.From.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p = obj.Appendp(ctxt, p)
p.As = ACMP
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R1
p.Reg = REG_R2
} else if framesize <= obj.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// SUB $framesize, SP, R2
// CMP stackguard, R2
p = obj.Appendp(ctxt, p)
p.As = ASUB
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(framesize)
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p = obj.Appendp(ctxt, p)
p.As = ACMP
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R1
p.Reg = REG_R2
} else {
// Such a large stack we need to protect against wraparound
// if SP is close to zero.
// SP-stackguard+StackGuard < framesize + (StackGuard-StackSmall)
// The +StackGuard on both sides is required to keep the left side positive:
// SP is allowed to be slightly below stackguard. See stack.h.
// CMP $StackPreempt, R1
// BEQ label_of_call_to_morestack
// ADD $StackGuard, SP, R2
// SUB R1, R2
// MOV $(framesize+(StackGuard-StackSmall)), R3
// CMP R3, R2
p = obj.Appendp(ctxt, p)
p.As = ACMP
p.From.Type = obj.TYPE_CONST
p.From.Offset = obj.StackPreempt
p.Reg = REG_R1
p = obj.Appendp(ctxt, p)
q = p
p.As = ABEQ
p.To.Type = obj.TYPE_BRANCH
p = obj.Appendp(ctxt, p)
p.As = AADD
p.From.Type = obj.TYPE_CONST
p.From.Offset = obj.StackGuard
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p = obj.Appendp(ctxt, p)
p.As = ASUB
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R1
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R2
p = obj.Appendp(ctxt, p)
p.As = AMOVD
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(framesize) + (obj.StackGuard - obj.StackSmall)
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R3
p = obj.Appendp(ctxt, p)
p.As = ACMP
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R3
p.Reg = REG_R2
}
// BLS do-morestack
bls := obj.Appendp(ctxt, p)
bls.As = ABLS
bls.To.Type = obj.TYPE_BRANCH
var last *obj.Prog
for last = ctxt.Cursym.Text; last.Link != nil; last = last.Link {
}
spfix := obj.Appendp(ctxt, last)
spfix.As = obj.ANOP
spfix.Spadj = -framesize
// MOV LR, R3
movlr := obj.Appendp(ctxt, spfix)
movlr.As = AMOVD
movlr.From.Type = obj.TYPE_REG
movlr.From.Reg = REGLINK
movlr.To.Type = obj.TYPE_REG
movlr.To.Reg = REG_R3
if q != nil {
q.Pcond = movlr
}
bls.Pcond = movlr
debug := movlr
if false {
debug = obj.Appendp(ctxt, debug)
debug.As = AMOVD
debug.From.Type = obj.TYPE_CONST
debug.From.Offset = int64(framesize)
debug.To.Type = obj.TYPE_REG
debug.To.Reg = REGTMP
}
// BL runtime.morestack(SB)
call := obj.Appendp(ctxt, debug)
call.As = ABL
call.To.Type = obj.TYPE_BRANCH
morestack := "runtime.morestack"
switch {
case ctxt.Cursym.Cfunc:
morestack = "runtime.morestackc"
case ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0:
morestack = "runtime.morestack_noctxt"
}
call.To.Sym = obj.Linklookup(ctxt, morestack, 0)
// B start
jmp := obj.Appendp(ctxt, call)
jmp.As = AB
jmp.To.Type = obj.TYPE_BRANCH
jmp.Pcond = ctxt.Cursym.Text.Link
jmp.Spadj = +framesize
// placeholder for bls's jump target
// p = obj.Appendp(ctxt, p)
// p.As = obj.ANOP
return bls
}
func progedit(ctxt *obj.Link, p *obj.Prog) {
p.From.Class = 0
p.To.Class = 0
// Rewrite BR/BL to symbol as TYPE_BRANCH.
switch p.As {
case ABR,
ABL,
obj.ARET,
obj.ADUFFZERO,
obj.ADUFFCOPY:
if p.To.Sym != nil {
p.To.Type = obj.TYPE_BRANCH
}
}
// Rewrite float constants to values stored in memory unless they are +0.
switch p.As {
case AFMOVS:
if p.From.Type == obj.TYPE_FCONST {
f32 := float32(p.From.Val.(float64))
i32 := math.Float32bits(f32)
if i32 == 0 { // +0
break
}
literal := fmt.Sprintf("$f32.%08x", i32)
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 4
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Sym.Local = true
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
case AFMOVD:
if p.From.Type == obj.TYPE_FCONST {
i64 := math.Float64bits(p.From.Val.(float64))
if i64 == 0 { // +0
break
}
literal := fmt.Sprintf("$f64.%016x", i64)
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 8
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Sym.Local = true
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
// put constants not loadable by LOAD IMMEDIATE into memory
case AMOVD:
if p.From.Type == obj.TYPE_CONST {
val := p.From.Offset
if int64(int32(val)) != val &&
int64(uint32(val)) != val &&
int64(uint64(val)&(0xffffffff<<32)) != val {
literal := fmt.Sprintf("$i64.%016x", uint64(p.From.Offset))
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 8
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Sym.Local = true
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
}
}
// Rewrite SUB constants into ADD.
switch p.As {
case ASUBC:
if p.From.Type == obj.TYPE_CONST {
p.From.Offset = -p.From.Offset
p.As = AADDC
}
case ASUB:
if p.From.Type == obj.TYPE_CONST {
p.From.Offset = -p.From.Offset
p.As = AADD
}
}
if ctxt.Flag_dynlink {
rewriteToUseGot(ctxt, p)
}
}
func progedit(ctxt *obj.Link, p *obj.Prog) {
p.From.Class = 0
p.To.Class = 0
// Rewrite JMP/JAL to symbol as TYPE_BRANCH.
switch p.As {
case AJMP,
AJAL,
ARET,
obj.ADUFFZERO,
obj.ADUFFCOPY:
if p.To.Sym != nil {
p.To.Type = obj.TYPE_BRANCH
}
}
// Rewrite float constants to values stored in memory.
switch p.As {
case AMOVF:
if p.From.Type == obj.TYPE_FCONST {
f32 := float32(p.From.Val.(float64))
i32 := math.Float32bits(f32)
literal := fmt.Sprintf("$f32.%08x", i32)
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 4
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
case AMOVD:
if p.From.Type == obj.TYPE_FCONST {
i64 := math.Float64bits(p.From.Val.(float64))
literal := fmt.Sprintf("$f64.%016x", i64)
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 8
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
// Put >32-bit constants in memory and load them
case AMOVV:
if p.From.Type == obj.TYPE_CONST && p.From.Name == obj.NAME_NONE && p.From.Reg == 0 && int64(int32(p.From.Offset)) != p.From.Offset {
literal := fmt.Sprintf("$i64.%016x", uint64(p.From.Offset))
s := obj.Linklookup(ctxt, literal, 0)
s.Size = 8
p.From.Type = obj.TYPE_MEM
p.From.Sym = s
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
}
// Rewrite SUB constants into ADD.
switch p.As {
case ASUB:
if p.From.Type == obj.TYPE_CONST {
p.From.Offset = -p.From.Offset
p.As = AADD
}
case ASUBU:
if p.From.Type == obj.TYPE_CONST {
p.From.Offset = -p.From.Offset
p.As = AADDU
}
case ASUBV:
if p.From.Type == obj.TYPE_CONST {
p.From.Offset = -p.From.Offset
p.As = AADDV
}
case ASUBVU:
if p.From.Type == obj.TYPE_CONST {
p.From.Offset = -p.From.Offset
p.As = AADDVU
}
}
}