From 06611434479daf7d27bd2cd69d10be7d4cb5cd61 Mon Sep 17 00:00:00 2001
From: Shenghou Ma <minux@golang.org>
Date: Fri, 6 Feb 2015 02:05:30 -0500
Subject: [PATCH] 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>
---
 src/liblink/asm5.c    |  8 +++++---
 src/runtime/asm_arm.s | 19 +------------------
 src/runtime/tls_arm.s | 21 +++++++++++++++++++++
 3 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/src/liblink/asm5.c b/src/liblink/asm5.c
index 7b4ac47e85..3947a571e5 100644
--- 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 a7c6c20cfe..2efeaaa531 100644
--- 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 2dbab722b0..d130d42cf2 100644
--- 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