cmd/internal/obj, cmd/link, runtime: a saner model for TLS on arm
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>
diff --git a/src/cmd/internal/obj/arm/a.out.go b/src/cmd/internal/obj/arm/a.out.go
index 6c9cfd5..ca166e1 100644
--- a/src/cmd/internal/obj/arm/a.out.go
+++ b/src/cmd/internal/obj/arm/a.out.go
@@ -155,6 +155,16 @@
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
diff --git a/src/cmd/internal/obj/arm/anames5.go b/src/cmd/internal/obj/arm/anames5.go
index 2e3a1f9..e3f98ce 100644
--- a/src/cmd/internal/obj/arm/anames5.go
+++ b/src/cmd/internal/obj/arm/anames5.go
@@ -41,6 +41,8 @@
"SP",
"HREG",
"ADDR",
+ "C_TLS_LE",
+ "C_TLS_IE",
"TEXTSIZE",
"GOK",
"NCLASS",
diff --git a/src/cmd/internal/obj/arm/asm5.go b/src/cmd/internal/obj/arm/asm5.go
index 1201296..60baa8d 100644
--- a/src/cmd/internal/obj/arm/asm5.go
+++ b/src/cmd/internal/obj/arm/asm5.go
@@ -104,6 +104,8 @@
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 @@
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 @@
}
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 @@
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)
diff --git a/src/cmd/link/internal/arm/asm.go b/src/cmd/link/internal/arm/asm.go
index a0e31a3..848d096 100644
--- a/src/cmd/link/internal/arm/asm.go
+++ b/src/cmd/link/internal/arm/asm.go
@@ -233,6 +233,12 @@
} 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
diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index 4263e8c..b8cf5b9 100644
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -395,15 +395,7 @@
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 @@
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 @@
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 @@
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' {
diff --git a/src/runtime/tls_arm.s b/src/runtime/tls_arm.s
index d37970e..4ff0ae4 100644
--- a/src/runtime/tls_arm.s
+++ b/src/runtime/tls_arm.s
@@ -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 @@
// 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 @@
// $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 @@
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 @@
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
