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cmd/7g: reserve registers R26 to R32

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These registers are not available for programs to use. Prior to this
change, the compiler would crash attempting to use ZR as a general
purpose register. Other programs would compile but on execution would
overwrite the G register and cause havoc.

Fixes linux/arm64 build.
Fixes #10304
Fixes #10320

Change-Id: I5cf51d3b77cfe3db7dd6377324950cafb02f8d8b
Reviewed-on: https://go-review.googlesource.com/8456
Reviewed-by: Minux Ma <minux@golang.org>
This commit is contained in:
David Crawshaw 2015-04-03 12:43:43 -04:00
parent a51d5f27e8
commit ca0adeddd5
2 changed files with 60 additions and 0 deletions
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5
src/cmd/7g/reg.go
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@ -115,6 +115,11 @@ func excludedregs() uint64 {
// Exclude registers with fixed functions
regbits := uint64(RtoB(arm64.REGRT1) | RtoB(arm64.REGRT2) | RtoB(arm64.REGPR))
// Exclude R26 - R31.
for r := arm64.REGMAX + 1; r <= arm64.REGZERO; r++ {
regbits |= RtoB(r)
}
// Also exclude floating point registers with fixed constants
regbits |= RtoB(arm64.REG_F27) | RtoB(arm64.REG_F28) | RtoB(arm64.REG_F29) | RtoB(arm64.REG_F30) | RtoB(arm64.REG_F31)

55
test/fixedbugs/issue10320.go Normal file
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@ -0,0 +1,55 @@
// run
// Copyright 2015 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.
// Issue 10320: 7g failed to compile a program because it attempted
// to use ZR as register. Other programs compiled but failed to
// execute correctly because they clobbered the g register.
package main
func main() {
var x00, x01, x02, x03, x04, x05, x06, x07, x08, x09 int
var x10, x11, x12, x13, x14, x15, x16, x17, x18, x19 int
var x20, x21, x22, x23, x24, x25, x26, x27, x28, x29 int
var x30, x31, x32 int
_ = x00
_ = x01
_ = x02
_ = x03
_ = x04
_ = x05
_ = x06
_ = x07
_ = x08
_ = x09
_ = x10
_ = x11
_ = x12
_ = x13
_ = x14
_ = x15
_ = x16
_ = x17
_ = x18
_ = x19
_ = x20
_ = x21
_ = x22
_ = x23
_ = x24
_ = x25
_ = x26
_ = x27
_ = x28
_ = x29
_ = x30
_ = x31
_ = x32
}