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cmd/internal/obj, cmd/link, runtime: a saner model for TLS on arm

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this leaves lots of cruft behind, will delete that soon

Change-Id: I12d6b6192f89bcdd89b2b0873774bd3458373b8a
Reviewed-on: https://go-review.googlesource.com/14196
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Michael Hudson-Doyle 2015-09-02 10:35:54 +12:00
parent b456aac388
commit b0344e9fd5
6 changed files with 104 additions and 30 deletions
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10
src/cmd/internal/obj/arm/a.out.go
View File

@ -155,6 +155,16 @@ const (
C_HREG
C_ADDR /* reference to relocatable address */
// TLS "var" in local exec mode: will become a constant offset from
// thread local base that is ultimately chosen by the program linker.
C_TLS_LE
// TLS "var" in initial exec mode: will become a memory address (chosen
// by the program linker) that the dynamic linker will fill with the
// offset from the thread local base.
C_TLS_IE
C_TEXTSIZE
C_GOK

2
src/cmd/internal/obj/arm/anames5.go
View File

@ -41,6 +41,8 @@ var cnames5 = []string{
"SP",
"HREG",
"ADDR",
"C_TLS_LE",
"C_TLS_IE",
"TEXTSIZE",
"GOK",
"NCLASS",

56
src/cmd/internal/obj/arm/asm5.go
View File

@ -104,6 +104,8 @@ var optab = []Optab{
Optab{AWORD, C_NONE, C_NONE, C_LCON, 11, 4, 0, 0, 0},
Optab{AWORD, C_NONE, C_NONE, C_LCONADDR, 11, 4, 0, 0, 0},
Optab{AWORD, C_NONE, C_NONE, C_ADDR, 11, 4, 0, 0, 0},
Optab{AWORD, C_NONE, C_NONE, C_TLS_LE, 103, 4, 0, 0, 0},
Optab{AWORD, C_NONE, C_NONE, C_TLS_IE, 104, 4, 0, 0, 0},
Optab{AMOVW, C_NCON, C_NONE, C_REG, 12, 4, 0, 0, 0},
Optab{AMOVW, C_LCON, C_NONE, C_REG, 12, 4, 0, LFROM, 0},
Optab{AMOVW, C_LCONADDR, C_NONE, C_REG, 12, 4, 0, LFROM | LPCREL, 4},
@ -151,6 +153,8 @@ var optab = []Optab{
Optab{AMOVBU, C_REG, C_NONE, C_LAUTO, 30, 8, REGSP, LTO, 0},
Optab{AMOVBU, C_REG, C_NONE, C_LOREG, 30, 8, 0, LTO, 0},
Optab{AMOVBU, C_REG, C_NONE, C_ADDR, 64, 8, 0, LTO | LPCREL, 4},
Optab{AMOVW, C_TLS_LE, C_NONE, C_REG, 101, 4, 0, LFROM, 0},
Optab{AMOVW, C_TLS_IE, C_NONE, C_REG, 102, 8, 0, LFROM, 0},
Optab{AMOVW, C_LAUTO, C_NONE, C_REG, 31, 8, REGSP, LFROM, 0},
Optab{AMOVW, C_LOREG, C_NONE, C_REG, 31, 8, 0, LFROM, 0},
Optab{AMOVW, C_ADDR, C_NONE, C_REG, 65, 8, 0, LFROM | LPCREL, 4},
@ -1016,6 +1020,14 @@ func aclass(ctxt *obj.Link, a *obj.Addr) int {
}
ctxt.Instoffset = 0 // s.b. unused but just in case
if a.Sym.Type == obj.STLSBSS {
if ctxt.Flag_shared != 0 {
return C_TLS_IE
} else {
return C_TLS_LE
}
}
return C_ADDR
case obj.NAME_AUTO:
@ -2037,6 +2049,50 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
o2 = oprrr(ctxt, AADD, int(p.Scond)) | REGTMP&15 | (REGPC&15)<<16 | (REGTMP&15)<<12
}
case 101: /* movw tlsvar,R, local exec*/
if p.Scond&C_SCOND != C_SCOND_NONE {
ctxt.Diag("conditional tls")
}
o1 = omvl(ctxt, p, &p.From, int(p.To.Reg))
case 102: /* movw tlsvar,R, initial exec*/
if p.Scond&C_SCOND != C_SCOND_NONE {
ctxt.Diag("conditional tls")
}
o1 = omvl(ctxt, p, &p.From, int(p.To.Reg))
o2 = olrr(ctxt, int(p.To.Reg)&15, (REGPC & 15), int(p.To.Reg), int(p.Scond))
case 103: /* word tlsvar, local exec */
if p.To.Sym == nil {
ctxt.Diag("nil sym in tls %v", p)
}
if p.To.Offset != 0 {
ctxt.Diag("offset against tls var in %v", p)
}
// This case happens with words generated in the PC stream as part of
// the literal pool.
rel := obj.Addrel(ctxt.Cursym)
rel.Off = int32(ctxt.Pc)
rel.Siz = 4
rel.Sym = p.To.Sym
rel.Type = obj.R_TLS_LE
o1 = 0
case 104: /* word tlsvar, initial exec */
if p.To.Sym == nil {
ctxt.Diag("nil sym in tls %v", p)
}
if p.To.Offset != 0 {
ctxt.Diag("offset against tls var in %v", p)
}
rel := obj.Addrel(ctxt.Cursym)
rel.Off = int32(ctxt.Pc)
rel.Siz = 4
rel.Sym = p.To.Sym
rel.Type = obj.R_TLS_IE
rel.Add = ctxt.Pc - p.Rel.Pc - 8 - int64(rel.Siz)
case 68: /* floating point store -> ADDR */
o1 = omvl(ctxt, p, &p.To, REGTMP)

6
src/cmd/link/internal/arm/asm.go
View File

@ -233,6 +233,12 @@ func elfreloc1(r *ld.Reloc, sectoff int64) int {
} else {
return -1
}
case obj.R_TLS_LE:
ld.Thearch.Lput(ld.R_ARM_TLS_LE32 | uint32(elfsym)<<8)
case obj.R_TLS_IE:
ld.Thearch.Lput(ld.R_ARM_TLS_IE32 | uint32(elfsym)<<8)
}
return 0

33
src/cmd/link/internal/ld/data.go
View File

@ -395,15 +395,7 @@ func relocsym(s *LSym) {
break
}
if Linkmode == LinkInternal && Iself && Thearch.Thechar == '5' {
// On ELF ARM, the thread pointer is 8 bytes before
// the start of the thread-local data block, so add 8
// to the actual TLS offset (r->sym->value).
// This 8 seems to be a fundamental constant of
// ELF on ARM (or maybe Glibc on ARM); it is not
// related to the fact that our own TLS storage happens
// to take up 8 bytes.
o = 8 + r.Sym.Value
panic("should no longer get here")
break
}
@ -416,8 +408,10 @@ func relocsym(s *LSym) {
case obj.R_TLS_LE:
if Linkmode == LinkExternal && Iself && HEADTYPE != obj.Hopenbsd {
r.Done = 0
r.Sym = Ctxt.Tlsg
r.Xsym = Ctxt.Tlsg
if r.Sym == nil {
r.Sym = Ctxt.Tlsg
}
r.Xsym = r.Sym
r.Xadd = r.Add
o = 0
if Thearch.Thechar != '6' {
@ -426,7 +420,16 @@ func relocsym(s *LSym) {
break
}
if Iself || Ctxt.Headtype == obj.Hplan9 || Ctxt.Headtype == obj.Hdarwin {
if Iself && Thearch.Thechar == '5' {
// On ELF ARM, the thread pointer is 8 bytes before
// the start of the thread-local data block, so add 8
// to the actual TLS offset (r->sym->value).
// This 8 seems to be a fundamental constant of
// ELF on ARM (or maybe Glibc on ARM); it is not
// related to the fact that our own TLS storage happens
// to take up 8 bytes.
o = 8 + r.Sym.Value
} else if Iself || Ctxt.Headtype == obj.Hplan9 || Ctxt.Headtype == obj.Hdarwin {
o = int64(Ctxt.Tlsoffset) + r.Add
} else if Ctxt.Headtype == obj.Hwindows {
o = r.Add
@ -437,8 +440,10 @@ func relocsym(s *LSym) {
case obj.R_TLS_IE:
if Linkmode == LinkExternal && Iself && HEADTYPE != obj.Hopenbsd {
r.Done = 0
r.Sym = Ctxt.Tlsg
r.Xsym = Ctxt.Tlsg
if r.Sym == nil {
r.Sym = Ctxt.Tlsg
}
r.Xsym = r.Sym
r.Xadd = r.Add
o = 0
if Thearch.Thechar != '6' {

27
src/runtime/tls_arm.s
View File

@ -15,7 +15,7 @@
// Note: both functions will clobber R0 and R11 and
// can be called from 5c ABI code.
// On android and darwin, runtime.tlsg is a normal variable.
// On android and darwin, runtime.tls_g is a normal variable.
// TLS offset is computed in x_cgo_inittls.
#ifdef GOOS_android
#define TLSG_IS_VARIABLE
@ -41,14 +41,7 @@ TEXT runtime·save_g(SB),NOSPLIT,$-4
// The replacement function saves LR in R11 over the call to read_tls_fallback.
MRC 15, 0, R0, C13, C0, 3 // fetch TLS base pointer
BIC $3, R0 // Darwin/ARM might return unaligned pointer
// $runtime.tlsg(SB) is a special linker symbol.
// It is the offset from the TLS base pointer to our
// thread-local storage for g.
#ifdef TLSG_IS_VARIABLE
MOVW runtime·tlsg(SB), R11
#else
MOVW $runtime·tlsg(SB), R11
#endif
MOVW runtime·tls_g(SB), R11
ADD R11, R0
MOVW g, 0(R0)
MOVW g, R0 // preserve R0 across call to setg<>
@ -68,11 +61,7 @@ TEXT runtime·load_g(SB),NOSPLIT,$0
// $runtime.tlsg(SB) is a special linker symbol.
// It is the offset from the TLS base pointer to our
// thread-local storage for g.
#ifdef TLSG_IS_VARIABLE
MOVW runtime·tlsg(SB), R11
#else
MOVW $runtime·tlsg(SB), R11
#endif
MOVW runtime·tls_g(SB), R11
ADD R11, R0
MOVW 0(R0), g
RET
@ -95,7 +84,11 @@ TEXT runtime·_initcgo(SB),NOSPLIT,$4
B.EQ nocgo
MRC 15, 0, R0, C13, C0, 3 // load TLS base pointer
MOVW R0, R3 // arg 3: TLS base pointer
MOVW $runtime·tlsg(SB), R2 // arg 2: tlsg
#ifdef TLSG_IS_VARIABLE
MOVW $runtime·tls_g(SB), R2 // arg 2: &tls_g
#else
MOVW $0, R2 // arg 2: not used when using platform tls
#endif
MOVW $setg_gcc<>(SB), R1 // arg 1: setg
MOVW g, R0 // arg 0: G
BL (R4) // will clobber R0-R3
@ -109,5 +102,7 @@ TEXT setg_gcc<>(SB),NOSPLIT,$0
B runtime·save_g(SB)
#ifdef TLSG_IS_VARIABLE
GLOBL runtime·tlsg+0(SB), NOPTR, $4
GLOBL runtime·tls_g+0(SB), NOPTR, $4
#else
GLOBL runtime·tls_g+0(SB), TLSBSS, $4
#endif