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Cherry Zhang authored
The argument size for runtime call was incorrectly includes the size of LR (FixedFrameSize in general). This makes the stack frame sometimes unnecessarily 4 bytes larger on ARM. For example, func f(b []byte) byte { return b[0] } compiles to 0x0000 00000 (h.go:6) TEXT "".f(SB), $4-16 // <-- framesize = 4 0x0000 00000 (h.go:6) MOVW 8(g), R1 0x0004 00004 (h.go:6) CMP R1, R13 0x0008 00008 (h.go:6) BLS 52 0x000c 00012 (h.go:6) MOVW.W R14, -8(R13) 0x0010 00016 (h.go:6) FUNCDATA $0, gclocals·8355ad952265fec823c17fcf739bd009(SB) 0x0010 00016 (h.go:6) FUNCDATA $1, gclocals·69c1753bd5f81501d95132d08af04464(SB) 0x0010 00016 (h.go:6) MOVW "".b+4(FP), R0 0x0014 00020 (h.go:6) CMP $0, R0 0x0018 00024 (h.go:6) BLS 44 0x001c 00028 (h.go:6) MOVW "".b(FP), R0 0x0020 00032 (h.go:6) MOVBU (R0), R0 0x0024 00036 (h.go:6) MOVB R0, "".~r1+12(FP) 0x0028 00040 (h.go:6) MOVW.P 8(R13), R15 0x002c 00044 (h.go:6) PCDATA $0, $1 0x002c 00044 (h.go:6) CALL runtime.panicindex(SB) 0x0030 00048 (h.go:6) UNDEF 0x0034 00052 (h.go:6) NOP 0x0034 00052 (h.go:6) MOVW R14, R3 0x0038 00056 (h.go:6) CALL runtime.morestack_noctxt(SB) 0x003c 00060 (h.go:6) JMP 0 Note that the frame size is 4, but there is actually no local. It incorrectly thinks call to runtime.panicindex needs 4 bytes space for argument. This CL fixes it. Updates #15365. Change-Id: Ic65d55283a6aa8a7861d7a3fbc7b63c35785eeec Reviewed-on: https://go-review.googlesource.com/24909 Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by:David Chase <drchase@google.com>
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