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| author | Keith Randall <khr@golang.org> | 2022-11-01 16:46:43 -0700 |
|---|---|---|
| committer | Keith Randall <khr@golang.org> | 2023-02-24 00:21:13 +0000 |
| commit | 21d82e6ac80fc2aea1eac9c8eec9afdd79cb5bdd (patch) | |
| tree | 293b975ed4dc782a0d68ab64dc6167b6d6486066 /src/runtime/asm_arm.s | |
| parent | f684f3dc434f9199ceee175c07d28e8b2b0f28dc (diff) | |
| download | go-21d82e6ac80fc2aea1eac9c8eec9afdd79cb5bdd.tar.xz | |
cmd/compile: batch write barrier calls
Have the write barrier call return a pointer to a buffer into which
the generated code records pointers that need write barrier treatment.
Change-Id: I7871764298e0aa1513de417010c8d46b296b199e
Reviewed-on: https://go-review.googlesource.com/c/go/+/447781
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Bypass: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Diffstat (limited to 'src/runtime/asm_arm.s')
| -rw-r--r-- | src/runtime/asm_arm.s | 44 |
1 files changed, 34 insertions, 10 deletions
diff --git a/src/runtime/asm_arm.s b/src/runtime/asm_arm.s index 3cabe748cd..569165ed19 100644 --- a/src/runtime/asm_arm.s +++ b/src/runtime/asm_arm.s @@ -870,16 +870,16 @@ TEXT ·checkASM(SB),NOSPLIT,$0-1 MOVB R3, ret+0(FP) RET -// gcWriteBarrier performs a heap pointer write and informs the GC. +// gcWriteBarrier informs the GC about heap pointer writes. // -// gcWriteBarrier does NOT follow the Go ABI. It takes two arguments: -// - R2 is the destination of the write -// - R3 is the value being written at R2 +// gcWriteBarrier does NOT follow the Go ABI. It accepts the +// number of bytes of buffer needed in R8, and returns a pointer +// to the buffer space in R8. // It clobbers condition codes. // It does not clobber any other general-purpose registers, // but may clobber others (e.g., floating point registers). // The act of CALLing gcWriteBarrier will clobber R14 (LR). -TEXT runtime·gcWriteBarrier(SB),NOSPLIT|NOFRAME,$0 +TEXT gcWriteBarrier<>(SB),NOSPLIT|NOFRAME,$0 // Save the registers clobbered by the fast path. MOVM.DB.W [R0,R1], (R13) retry: @@ -888,16 +888,15 @@ retry: MOVW (p_wbBuf+wbBuf_next)(R0), R1 MOVW (p_wbBuf+wbBuf_end)(R0), R11 // Increment wbBuf.next position. - ADD $8, R1 + ADD R8, R1 // Is the buffer full? CMP R11, R1 BHI flush // Commit to the larger buffer. MOVW R1, (p_wbBuf+wbBuf_next)(R0) - // Record the write. - MOVW R3, -8(R1) // Record value - MOVW (R2), R0 // TODO: This turns bad writes into bad reads. - MOVW R0, -4(R1) // Record *slot + // Make return value (the original next position) + SUB R8, R1, R8 + // Restore registers. MOVM.IA.W (R13), [R0,R1] RET @@ -921,6 +920,31 @@ flush: MOVM.IA.W (R13), [R2-R9,R12] JMP retry +TEXT runtime·gcWriteBarrier1<ABIInternal>(SB),NOSPLIT,$0 + MOVW $4, R8 + JMP gcWriteBarrier<>(SB) +TEXT runtime·gcWriteBarrier2<ABIInternal>(SB),NOSPLIT,$0 + MOVW $8, R8 + JMP gcWriteBarrier<>(SB) +TEXT runtime·gcWriteBarrier3<ABIInternal>(SB),NOSPLIT,$0 + MOVW $12, R8 + JMP gcWriteBarrier<>(SB) +TEXT runtime·gcWriteBarrier4<ABIInternal>(SB),NOSPLIT,$0 + MOVW $16, R8 + JMP gcWriteBarrier<>(SB) +TEXT runtime·gcWriteBarrier5<ABIInternal>(SB),NOSPLIT,$0 + MOVW $20, R8 + JMP gcWriteBarrier<>(SB) +TEXT runtime·gcWriteBarrier6<ABIInternal>(SB),NOSPLIT,$0 + MOVW $24, R8 + JMP gcWriteBarrier<>(SB) +TEXT runtime·gcWriteBarrier7<ABIInternal>(SB),NOSPLIT,$0 + MOVW $28, R8 + JMP gcWriteBarrier<>(SB) +TEXT runtime·gcWriteBarrier8<ABIInternal>(SB),NOSPLIT,$0 + MOVW $32, R8 + JMP gcWriteBarrier<>(SB) + // Note: these functions use a special calling convention to save generated code space. // Arguments are passed in registers, but the space for those arguments are allocated // in the caller's stack frame. These stubs write the args into that stack space and |