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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| AUTHORS | ||
| CONTRIBUTING.md | ||
| CONTRIBUTORS | ||
| LICENSE | ||
| PATENTS | ||
| README.md | ||
| favicon.ico | ||
| robots.txt | ||
README.md
The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
For documentation about how to install and use Go, visit https://golang.org/ or load doc/install-source.html in your web browser.
Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.
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To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
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Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
--
Binary Distribution Notes
If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.
For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:
export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin
See https://golang.org/doc/install or doc/install.html for more details.
