runtime: align C library startup calls on amd64

This makes GOEXPERIMENT=framepointer, GOOS=darwin, and buildmode=carchive coexist. Change-Id: I9f6fb2f0f06f27df683e5b51f2fa55cd21872453 Reviewed-on: https://go-review.googlesource.com/23454 Reviewed-by: Austin Clements <[email protected]>
beoran · May 25, 2016 · 10c8b23 · 10c8b23
1 parent 3be48b4
commit 10c8b23
Showing 1 changed file with 11 additions and 1 deletion.
diff --git a/src/runtime/rt0_darwin_amd64.s b/src/runtime/rt0_darwin_amd64.s
@@ -12,7 +12,14 @@ TEXT _rt0_amd64_darwin(SB),NOSPLIT,$-8
 
 // When linking with -shared, this symbol is called when the shared library
 // is loaded.
-TEXT _rt0_amd64_darwin_lib(SB),NOSPLIT,$0x48
+TEXT _rt0_amd64_darwin_lib(SB),NOSPLIT,$0x58
+	// Align stack. We don't know whether Go is adding a frame pointer here or not.
+	MOVQ	SP, R8
+	SUBQ	$16, R8
+	ANDQ	$~15, R8
+	XCHGQ	SP, R8
+
+	MOVQ	R8, 0x48(SP)
 	MOVQ	BX, 0x18(SP)
 	MOVQ	BP, 0x20(SP)
 	MOVQ	R12, 0x28(SP)
@@ -51,6 +58,9 @@ restore:
 	MOVQ	0x30(SP), R13
 	MOVQ	0x38(SP), R14
 	MOVQ	0x40(SP), R15
+
+	MOVQ	0x48(SP), R8
+	MOVQ	R8, SP
 	RET
 
 TEXT _rt0_amd64_darwin_lib_go(SB),NOSPLIT,$0