diff options
Diffstat (limited to 'src/runtime/asm_amd64.s')
| -rw-r--r-- | src/runtime/asm_amd64.s | 65 |
1 files changed, 25 insertions, 40 deletions
diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s index fa25c55b96..19a3bb2d7d 100644 --- a/src/runtime/asm_amd64.s +++ b/src/runtime/asm_amd64.s @@ -470,6 +470,7 @@ TEXT runtime·morestack_noctxt(SB),NOSPLIT,$0 TEXT ·reflectcall(SB), NOSPLIT, $0-32 MOVLQZX argsize+24(FP), CX + DISPATCH(runtime·call16, 16) DISPATCH(runtime·call32, 32) DISPATCH(runtime·call64, 64) DISPATCH(runtime·call128, 128) @@ -537,6 +538,7 @@ TEXT callRet<>(SB), NOSPLIT, $32-0 CALL runtime·reflectcallmove(SB) RET +CALLFN(·call16, 16) CALLFN(·call32, 32) CALLFN(·call64, 64) CALLFN(·call128, 128) @@ -689,25 +691,9 @@ nosave: MOVL AX, ret+16(FP) RET -// func cgocallback(fn, frame unsafe.Pointer, framesize, ctxt uintptr) -// Turn the fn into a Go func (by taking its address) and call -// cgocallback_gofunc. -TEXT runtime·cgocallback(SB),NOSPLIT,$32-32 - LEAQ fn+0(FP), AX - MOVQ AX, 0(SP) - MOVQ frame+8(FP), AX - MOVQ AX, 8(SP) - MOVQ framesize+16(FP), AX - MOVQ AX, 16(SP) - MOVQ ctxt+24(FP), AX - MOVQ AX, 24(SP) - MOVQ $runtime·cgocallback_gofunc(SB), AX - CALL AX - RET - -// func cgocallback_gofunc(fn, frame, framesize, ctxt uintptr) +// func cgocallback(fn, frame unsafe.Pointer, ctxt uintptr) // See cgocall.go for more details. -TEXT ·cgocallback_gofunc(SB),NOSPLIT,$16-32 +TEXT ·cgocallback(SB),NOSPLIT,$24-24 NO_LOCAL_POINTERS // If g is nil, Go did not create the current thread. @@ -725,13 +711,12 @@ TEXT ·cgocallback_gofunc(SB),NOSPLIT,$16-32 CMPQ BX, $0 JEQ needm MOVQ g_m(BX), BX - MOVQ BX, R8 // holds oldm until end of function + MOVQ BX, savedm-8(SP) // saved copy of oldm JMP havem needm: - MOVQ $0, 0(SP) - MOVQ $runtime·needm(SB), AX + MOVQ $runtime·needm(SB), AX CALL AX - MOVQ 0(SP), R8 + MOVQ $0, savedm-8(SP) // dropm on return get_tls(CX) MOVQ g(CX), BX MOVQ g_m(BX), BX @@ -767,37 +752,36 @@ havem: // save that information (m->curg->sched) so we can restore it. // We can restore m->curg->sched.sp easily, because calling // runtime.cgocallbackg leaves SP unchanged upon return. - // To save m->curg->sched.pc, we push it onto the stack. - // This has the added benefit that it looks to the traceback - // routine like cgocallbackg is going to return to that - // PC (because the frame we allocate below has the same - // size as cgocallback_gofunc's frame declared above) - // so that the traceback will seamlessly trace back into - // the earlier calls. - // - // In the new goroutine, 8(SP) holds the saved R8. + // To save m->curg->sched.pc, we push it onto the curg stack and + // open a frame the same size as cgocallback's g0 frame. + // Once we switch to the curg stack, the pushed PC will appear + // to be the return PC of cgocallback, so that the traceback + // will seamlessly trace back into the earlier calls. MOVQ m_curg(BX), SI MOVQ SI, g(CX) MOVQ (g_sched+gobuf_sp)(SI), DI // prepare stack as DI MOVQ (g_sched+gobuf_pc)(SI), BX - MOVQ BX, -8(DI) + MOVQ BX, -8(DI) // "push" return PC on the g stack + // Gather our arguments into registers. + MOVQ fn+0(FP), BX + MOVQ frame+8(FP), CX + MOVQ ctxt+16(FP), DX // Compute the size of the frame, including return PC and, if // GOEXPERIMENT=framepointer, the saved base pointer - MOVQ ctxt+24(FP), BX - LEAQ fv+0(FP), AX - SUBQ SP, AX - SUBQ AX, DI + LEAQ fn+0(FP), AX + SUBQ SP, AX // AX is our actual frame size + SUBQ AX, DI // Allocate the same frame size on the g stack MOVQ DI, SP - MOVQ R8, 8(SP) MOVQ BX, 0(SP) + MOVQ CX, 8(SP) + MOVQ DX, 16(SP) CALL runtime·cgocallbackg(SB) - MOVQ 8(SP), R8 // Compute the size of the frame again. FP and SP have // completely different values here than they did above, // but only their difference matters. - LEAQ fv+0(FP), AX + LEAQ fn+0(FP), AX SUBQ SP, AX // Restore g->sched (== m->curg->sched) from saved values. @@ -822,7 +806,8 @@ havem: // 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. - CMPQ R8, $0 + MOVQ savedm-8(SP), BX + CMPQ BX, $0 JNE 3(PC) MOVQ $runtime·dropm(SB), AX CALL AX |