diff options
Diffstat (limited to 'src/runtime/asm_amd64.s')
| -rw-r--r-- | src/runtime/asm_amd64.s | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s index 45afcda38f..6acb7ddaef 100644 --- a/src/runtime/asm_amd64.s +++ b/src/runtime/asm_amd64.s @@ -1634,15 +1634,20 @@ TEXT runtime·gcWriteBarrier<ABIInternal>(SB),NOSPLIT,$112 // faster than having the caller spill these. MOVQ R12, 96(SP) MOVQ R13, 104(SP) +retry: // TODO: Consider passing g.m.p in as an argument so they can be shared // across a sequence of write barriers. MOVQ g_m(R14), R13 MOVQ m_p(R13), R13 + // Get current buffer write position. MOVQ (p_wbBuf+wbBuf_next)(R13), R12 // Increment wbBuf.next position. LEAQ 16(R12), R12 - MOVQ R12, (p_wbBuf+wbBuf_next)(R13) + // Is the buffer full? CMPQ R12, (p_wbBuf+wbBuf_end)(R13) + JA flush + // Commit to the larger buffer. + MOVQ R12, (p_wbBuf+wbBuf_next)(R13) // Record the write. MOVQ AX, -16(R12) // Record value // Note: This turns bad pointer writes into bad @@ -1653,9 +1658,6 @@ TEXT runtime·gcWriteBarrier<ABIInternal>(SB),NOSPLIT,$112 // combine the read and the write. MOVQ (DI), R13 MOVQ R13, -8(R12) // Record *slot - // Is the buffer full? (flags set in CMPQ above) - JEQ flush -ret: MOVQ 96(SP), R12 MOVQ 104(SP), R13 // Do the write. @@ -1675,8 +1677,8 @@ flush: // // TODO: We could strike a different balance; e.g., saving X0 // and not saving GP registers that are less likely to be used. - MOVQ DI, 0(SP) // Also first argument to wbBufFlush - MOVQ AX, 8(SP) // Also second argument to wbBufFlush + MOVQ DI, 0(SP) + MOVQ AX, 8(SP) MOVQ BX, 16(SP) MOVQ CX, 24(SP) MOVQ DX, 32(SP) @@ -1692,7 +1694,6 @@ flush: // R14 is g MOVQ R15, 88(SP) - // This takes arguments DI and AX CALL runtime·wbBufFlush(SB) MOVQ 0(SP), DI @@ -1707,7 +1708,7 @@ flush: MOVQ 72(SP), R10 MOVQ 80(SP), R11 MOVQ 88(SP), R15 - JMP ret + JMP retry // gcWriteBarrierCX is gcWriteBarrier, but with args in DI and CX. // Defined as ABIInternal since it does not use the stable Go ABI. |