| Index: src/pkg/runtime/asm_amd64.s |
| =================================================================== |
| --- a/src/pkg/runtime/asm_amd64.s |
| +++ b/src/pkg/runtime/asm_amd64.s |
| @@ -563,7 +563,7 @@ |
| // cgocallback_gofunc(FuncVal*, void *frame, uintptr framesize) |
| // See cgocall.c for more details. |
| -TEXT runtime·cgocallback_gofunc(SB),7,$16-24 |
| +TEXT runtime·cgocallback_gofunc(SB),7,$8-24 |
| // If m is nil, Go did not create the current thread. |
| // Call needm to obtain one for temporary use. |
| // In this case, we're running on the thread stack, so there's |
| @@ -576,12 +576,14 @@ |
| JEQ 2(PC) |
| #endif |
| MOVQ m(CX), BP |
| - MOVQ BP, 8(SP) |
| + MOVQ BP, R8 // holds oldm until end of function |
| CMPQ BP, $0 |
| JNE havem |
| needm: |
| + MOVQ R8, 0(SP) |
| MOVQ $runtime·needm(SB), AX |
| CALL AX |
| + MOVQ 0(SP), R8 |
| get_tls(CX) |
| MOVQ m(CX), BP |
| @@ -610,22 +612,23 @@ |
| // so that the traceback will seamlessly trace back into |
| // the earlier calls. |
| // |
| - // In the new goroutine, 0(SP) and 8(SP) are unused except |
| - // on Windows, where they are the SEH block. |
| + // In the new goroutine, 0(SP) holds the saved R8. |
| MOVQ m_curg(BP), SI |
| MOVQ SI, g(CX) |
| MOVQ (g_sched+gobuf_sp)(SI), DI // prepare stack as DI |
| MOVQ (g_sched+gobuf_pc)(SI), BP |
| MOVQ BP, -8(DI) |
| - LEAQ -(8+16)(DI), SP |
| + LEAQ -(8+8)(DI), SP |
| + MOVQ R8, 0(SP) |
| CALL runtime·cgocallbackg(SB) |
| + MOVQ 0(SP), R8 |
| // Restore g->sched (== m->curg->sched) from saved values. |
| get_tls(CX) |
| MOVQ g(CX), SI |
| - MOVQ 16(SP), BP |
| + MOVQ 8(SP), BP |
| MOVQ BP, (g_sched+gobuf_pc)(SI) |
| - LEAQ (16+8)(SP), DI |
| + LEAQ (8+8)(SP), DI |
| MOVQ DI, (g_sched+gobuf_sp)(SI) |
| // Switch back to m->g0's stack and restore m->g0->sched.sp. |
| @@ -640,8 +643,7 @@ |
| // If the m on entry was nil, we called needm above to borrow an m |
| // for the duration of the call. Since the call is over, return it with dropm. |
| - MOVQ 8(SP), BP |
| - CMPQ BP, $0 |
| + CMPQ R8, $0 |
| JNE 3(PC) |
| MOVQ $runtime·dropm(SB), AX |
| CALL AX |
