liblink, runtime: move all references to runtime.tlsg to tls_arm.s

CL 2118 makes the assumption that all references to runtime.tlsg
should be accompanied by a declaration of runtime.tlsg if its type
should be a normal variable, instead of a placeholder for TLS
relocation.

Because if runtime.tlsg is not declared by the runtime package,
the type of runtime.tlsg will be zero, so fix the check in liblink
to look for 0 instead of STLSBSS (the type will be initialized by
cmd/ld, but cmd/ld doesn't run during assembly).

Change-Id: I691ac5c3faea902f8b9a0b963e781b22e7b269a7
Reviewed-on: https://go-review.googlesource.com/4030
Reviewed-by: David Crawshaw <crawshaw@golang.org>

diff --git a/src/liblink/asm5.c b/src/liblink/asm5.c
index 7b4ac47e852cbbc1b557049d053a338dc38f3223..3947a571e5c7c07e7e126a31931649b9e69181fd 100644 (file)
--- a/src/liblink/asm5.c
+++ b/src/liblink/asm5.c
@@ -1638,9 +1638,11 @@ 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 it's
-                       // typed STLSBSS.
-                       if(rel->sym == ctxt->tlsg && ctxt->tlsg->type == STLSBSS) {
+                       // Emit a TLS relocation instead of a standard one if its
+                       // type is not explicitly set by runtime. This assumes that
+                       // all references to runtime.tlsg should be accompanied with
+                       // its type declaration if necessary.
+                       if(rel->sym == ctxt->tlsg && ctxt->tlsg->type == 0) {
                                rel->type = R_TLS;
                                if(ctxt->flag_shared)
                                        rel->add += ctxt->pc - p->pcrel->pc - 8 - rel->siz;

diff --git a/src/runtime/asm_arm.s b/src/runtime/asm_arm.s
index a7c6c20cfe8fb28c6c5022045d5a1eab5ecde754..2efeaaa5310589e58141d93a1d4a1fd4ccf51c08 100644 (file)
--- a/src/runtime/asm_arm.s
+++ b/src/runtime/asm_arm.s
@@ -39,20 +39,8 @@ TEXT runtime·rt0_go(SB),NOSPLIT,$-4
 
        BL      runtime·emptyfunc(SB)  // fault if stack check is wrong
 
-#ifndef GOOS_nacl
-       // if there is an _cgo_init, call it.
-       MOVW    _cgo_init(SB), R4
-       CMP     $0, R4
-       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
-       MOVW    $setg_gcc<>(SB), R1     // arg 1: setg
-       MOVW    g, R0                   // arg 0: G
-       BL      (R4) // will clobber R0-R3
-#endif
+       BL      runtime·_initcgo(SB)   // will clobber R0-R3
 
-nocgo:
        // update stackguard after _cgo_init
        MOVW    (g_stack+stack_lo)(g), R0
        ADD     $const__StackGuard, R0
@@ -830,11 +818,6 @@ loop:
        MOVB    R8, v+16(FP)
        RET
 
-// void setg_gcc(G*); set g called from gcc.
-TEXT setg_gcc<>(SB),NOSPLIT,$0
-       MOVW    R0, g
-       B               runtime·save_g(SB)
-
 // TODO: share code with memeq?
 TEXT bytes·Equal(SB),NOSPLIT,$0
        MOVW    a_len+4(FP), R1

diff --git a/src/runtime/tls_arm.s b/src/runtime/tls_arm.s
index 2dbab722b072519fa2a6955181f902e1a47482a3..d130d42cf2ef7e8bcf1a81eb32249fc35db1dd83 100644 (file)
--- a/src/runtime/tls_arm.s
+++ b/src/runtime/tls_arm.s
@@ -77,6 +77,27 @@ TEXT runtime·load_g(SB),NOSPLIT,$0
        MOVW    0(R0), g
        RET
 
+TEXT runtime·_initcgo(SB),NOSPLIT,$0
+#ifndef GOOS_nacl
+       // if there is an _cgo_init, call it.
+       MOVW    _cgo_init(SB), R4
+       CMP     $0, R4
+       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
+       MOVW    $setg_gcc<>(SB), R1     // arg 1: setg
+       MOVW    g, R0                   // arg 0: G
+       BL      (R4) // will clobber R0-R3
+#endif
+nocgo:
+       RET
+
+// void setg_gcc(G*); set g called from gcc.
+TEXT setg_gcc<>(SB),NOSPLIT,$0
+       MOVW    R0, g
+       B               runtime·save_g(SB)
+
 #ifdef TLSG_IS_VARIABLE
 GLOBL runtime·tlsg+0(SB), NOPTR, $4
 #endif