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liblink, cmd/ld, runtime: set the type of runtime.tlsg in runtime 

In the old code, liblink, cmd/ld and runtime all have code determine
whether runtime.tlsg is an actual variable or a placeholder for TLS
relocation. This change consolidate them into one: the runtime/tls_arm.s
will ultimately determine the type of that variable.

Change-Id: I3b3f80791a1db4c2b7318f81a115972cd2237e43
Reviewed-on: https://go-review.googlesource.com/2118
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
This commit is contained in:
Shenghou Ma 2014-12-26 00:48:33 -05:00 committed by Minux Ma
parent 3819907a55
commit d738c6b0ca
3 changed files with 19 additions and 5 deletions
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8
src/cmd/ld/lib.c
View File

@ -257,7 +257,13 @@ loadlib(void)
}
tlsg = linklookup(ctxt, "runtime.tlsg", 0);
tlsg->type = STLSBSS;
// For most ports, runtime.tlsg is a placeholder symbol for TLS
// relocation. However, the Android and Darwin ports need it to
// be a real variable. Instead of hard-coding which platforms
// need it to be a real variable, we set the type to STLSBSS only
// when the runtime has not declared its type already.
if(tlsg->type == 0)
tlsg->type = STLSBSS;
tlsg->size = PtrSize;
tlsg->hide = 1;
tlsg->reachable = 1;

5
src/liblink/asm5.c
View File

@ -1638,8 +1638,9 @@ if(0 /*debug['G']*/) print("%ux: %s: arm %d\n", (uint32)(p->pc), p->from.sym->na
// runtime.tlsg is special.
// Its "address" is the offset from the TLS thread pointer
// to the thread-local g and m pointers.
// Emit a TLS relocation instead of a standard one.
if(rel->sym == ctxt->tlsg) {
// Emit a TLS relocation instead of a standard one if it's
// typed STLSBSS.
if(rel->sym == ctxt->tlsg && ctxt->tlsg->type == STLSBSS) {
rel->type = R_TLS;
if(ctxt->flag_shared)
rel->add += ctxt->pc - p->pcrel->pc - 8 - rel->siz;

11
src/runtime/tls_arm.s
View File

@ -17,6 +17,9 @@
// On android, runtime.tlsg is a normal variable.
// TLS offset is computed in x_cgo_inittls.
#ifdef GOOS_android
#define TLSG_IS_VARIABLE
#endif
// save_g saves the g register into pthread-provided
// thread-local memory, so that we can call externally compiled
@ -37,7 +40,7 @@ TEXT runtime·save_g(SB),NOSPLIT,$-4
// $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 GOOS_android
#ifdef TLSG_IS_VARIABLE
MOVW runtime·tlsg(SB), R11
#else
MOVW $runtime·tlsg(SB), R11
@ -60,7 +63,7 @@ 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 GOOS_android
#ifdef TLSG_IS_VARIABLE
MOVW runtime·tlsg(SB), R11
#else
MOVW $runtime·tlsg(SB), R11
@ -68,3 +71,7 @@ TEXT runtime·load_g(SB),NOSPLIT,$0
ADD R11, R0
MOVW 0(R0), g
RET
#ifdef TLSG_IS_VARIABLE
GLOBL runtime·tlsg+0(SB), NOPTR, $4
#endif