cmd/cgo, runtime, runtime/cgo: use cgo context function
Add support for the context function set by runtime.SetCgoTraceback.
The context function was added in CL 17761, without support.
This CL is the support.
This CL has not been tested for real C code, as a working context
function for C code requires unwind support that does not seem to exist.
I wanted to get the CL out before the freeze.
I apologize for the length of this CL. It's mostly plumbing, but
unfortunately the plumbing is processor-specific.
Change-Id: I8ce11a0de9b3dafcc29efd2649d776e93bff0e90
Reviewed-on: https://go-review.googlesource.com/22508
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s
index dec7918..530fbb0e 100644
--- a/src/runtime/asm_386.s
+++ b/src/runtime/asm_386.s
@@ -612,23 +612,25 @@
MOVL AX, ret+8(FP)
RET
-// cgocallback(void (*fn)(void*), void *frame, uintptr framesize)
+// cgocallback(void (*fn)(void*), void *frame, uintptr framesize, uintptr ctxt)
// Turn the fn into a Go func (by taking its address) and call
// cgocallback_gofunc.
-TEXT runtime·cgocallback(SB),NOSPLIT,$12-12
+TEXT runtime·cgocallback(SB),NOSPLIT,$16-16
LEAL fn+0(FP), AX
MOVL AX, 0(SP)
MOVL frame+4(FP), AX
MOVL AX, 4(SP)
MOVL framesize+8(FP), AX
MOVL AX, 8(SP)
+ MOVL ctxt+12(FP), AX
+ MOVL AX, 12(SP)
MOVL $runtime·cgocallback_gofunc(SB), AX
CALL AX
RET
-// cgocallback_gofunc(FuncVal*, void *frame, uintptr framesize)
+// cgocallback_gofunc(FuncVal*, void *frame, uintptr framesize, uintptr ctxt)
// See cgocall.go for more details.
-TEXT ·cgocallback_gofunc(SB),NOSPLIT,$12-12
+TEXT ·cgocallback_gofunc(SB),NOSPLIT,$12-16
NO_LOCAL_POINTERS
// If g is nil, Go did not create the current thread.
@@ -696,17 +698,19 @@
// so that the traceback will seamlessly trace back into
// the earlier calls.
//
- // In the new goroutine, 0(SP) holds the saved oldm (DX) register.
- // 4(SP) and 8(SP) are unused.
+ // In the new goroutine, 4(SP) holds the saved oldm (DX) register.
+ // 8(SP) is unused.
MOVL m_curg(BP), SI
MOVL SI, g(CX)
MOVL (g_sched+gobuf_sp)(SI), DI // prepare stack as DI
MOVL (g_sched+gobuf_pc)(SI), BP
MOVL BP, -4(DI)
+ MOVL ctxt+12(FP), CX
LEAL -(4+12)(DI), SP
- MOVL DX, 0(SP)
+ MOVL DX, 4(SP)
+ MOVL CX, 0(SP)
CALL runtime·cgocallbackg(SB)
- MOVL 0(SP), DX
+ MOVL 4(SP), DX
// Restore g->sched (== m->curg->sched) from saved values.
get_tls(CX)
