diff options
author | Austin Clements <austin@google.com> | 2021-08-06 17:01:25 -0400 |
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committer | Austin Clements <austin@google.com> | 2021-10-30 18:30:05 +0000 |
commit | f582778ee991e8a443e691f9a45c8f0600a748a0 (patch) | |
tree | 6c6f4949dd613501b6d62a8d9854779867da8005 /test | |
parent | 30b5d6385e91ab557978c0024a9eb90e656623b7 (diff) | |
download | go-git-f582778ee991e8a443e691f9a45c8f0600a748a0.tar.gz |
cmd/compile: emit sensible go_asm.h consts for big ints
Currently, the compiler will emit any const that doesn't fit in an
int64 to go_asm.h like
#define const_stackPreempt constant.intVal{val:(*big.Int)(0xc000c06c40)}
This happens because dumpasmhdr formats the constant.Value using the
verb "%#v". Since constant.Value doesn't implement the GoString()
method, this just prints the Go-syntax representation of the value.
This happens to work for small integer constants, which go/constant
represents directly as an int64, but not for integer constants that
don't fit in an int64, which go/constant represents as a big.Int.
Make these constants usable by changing the formatting verb to "%v",
which will call the String() method, giving a reasonable result in all
cases.
Change-Id: I365eeb88c8acfc43ff377cc873432269bde3f541
Reviewed-on: https://go-review.googlesource.com/c/go/+/359954
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Diffstat (limited to 'test')
-rw-r--r-- | test/asmhdr.dir/main.go | 66 | ||||
-rw-r--r-- | test/asmhdr.dir/main.s | 27 | ||||
-rw-r--r-- | test/asmhdr.go | 9 |
3 files changed, 102 insertions, 0 deletions
diff --git a/test/asmhdr.dir/main.go b/test/asmhdr.dir/main.go new file mode 100644 index 0000000000..808b5de7bb --- /dev/null +++ b/test/asmhdr.dir/main.go @@ -0,0 +1,66 @@ +// Copyright 2021 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package main + +import "unsafe" + +const ( + smallInt = 42 + + // For bigInt, we use a value that's too big for an int64, but still + // fits in uint64. go/constant uses a different representation for + // values larger than int64, but the cmd/asm parser can't parse + // anything bigger than a uint64. + bigInt = 0xffffffffffffffff + + stringVal = "test" +) + +var ( + smallIntAsm int64 + bigIntAsm uint64 + stringAsm [len(stringVal)]byte +) + +type typ struct { + a uint64 + b [100]uint8 + c uint8 +} + +var ( + typSize uint64 + + typA, typB, typC uint64 +) + +func main() { + if smallInt != smallIntAsm { + println("smallInt", smallInt, "!=", smallIntAsm) + } + if bigInt != bigIntAsm { + println("bigInt", uint64(bigInt), "!=", bigIntAsm) + } + if stringVal != string(stringAsm[:]) { + println("stringVal", stringVal, "!=", string(stringAsm[:])) + } + + // We also include boolean consts in go_asm.h, but they're + // defined to be "true" or "false", and it's not clear how to + // use that in assembly. + + if want := unsafe.Sizeof(typ{}); want != uintptr(typSize) { + println("typSize", want, "!=", typSize) + } + if want := unsafe.Offsetof(typ{}.a); want != uintptr(typA) { + println("typA", want, "!=", typA) + } + if want := unsafe.Offsetof(typ{}.b); want != uintptr(typB) { + println("typB", want, "!=", typB) + } + if want := unsafe.Offsetof(typ{}.c); want != uintptr(typC) { + println("typC", want, "!=", typC) + } +} diff --git a/test/asmhdr.dir/main.s b/test/asmhdr.dir/main.s new file mode 100644 index 0000000000..7e2d8e7abd --- /dev/null +++ b/test/asmhdr.dir/main.s @@ -0,0 +1,27 @@ +// Copyright 2021 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "go_asm.h" +#define RODATA 8 + +DATA ·smallIntAsm(SB)/8, $const_smallInt +GLOBL ·smallIntAsm(SB),RODATA,$8 + +DATA ·bigIntAsm(SB)/8, $const_bigInt +GLOBL ·bigIntAsm(SB),RODATA,$8 + +DATA ·stringAsm(SB)/4, $const_stringVal +GLOBL ·stringAsm(SB),RODATA,$4 + +DATA ·typSize(SB)/8, $typ__size +GLOBL ·typSize(SB),RODATA,$8 + +DATA ·typA(SB)/8, $typ_a +GLOBL ·typA(SB),RODATA,$8 + +DATA ·typB(SB)/8, $typ_b +GLOBL ·typB(SB),RODATA,$8 + +DATA ·typC(SB)/8, $typ_c +GLOBL ·typC(SB),RODATA,$8 diff --git a/test/asmhdr.go b/test/asmhdr.go new file mode 100644 index 0000000000..772f98e2cc --- /dev/null +++ b/test/asmhdr.go @@ -0,0 +1,9 @@ +// buildrundir + +// Copyright 2021 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Test the -asmhdr output of the compiler. + +package ignored |