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		187fd2698d
		
	
	
	
	
		
			
			It currently isn't because it does load/store/load/store/... Rework to do overwrite processing in pairs so it is instead load/load/store/store/... Change-Id: If7be629bc4048da5f2386dafb8f05759b79e9e2b Reviewed-on: https://go-review.googlesource.com/c/go/+/631495 Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Keith Randall <khr@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
		
			
				
	
	
		
			103 lines
		
	
	
	
		
			2.6 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			103 lines
		
	
	
	
		
			2.6 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
| // asmcheck
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| 
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| // Copyright 2023 The Go Authors. All rights reserved.
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| // Use of this source code is governed by a BSD-style
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| // license that can be found in the LICENSE file.
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| 
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| package codegen
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| 
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| func combine2string(p *[2]string, a, b string) {
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| 	// amd64:`.*runtime[.]gcWriteBarrier4\(SB\)`
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| 	// arm64:`.*runtime[.]gcWriteBarrier4\(SB\)`
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| 	p[0] = a
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| 	// amd64:-`.*runtime[.]gcWriteBarrier`
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| 	// arm64:-`.*runtime[.]gcWriteBarrier`
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| 	p[1] = b
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| }
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| 
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| func combine4string(p *[4]string, a, b, c, d string) {
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| 	// amd64:`.*runtime[.]gcWriteBarrier8\(SB\)`
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| 	// arm64:`.*runtime[.]gcWriteBarrier8\(SB\)`
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| 	p[0] = a
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| 	// amd64:-`.*runtime[.]gcWriteBarrier`
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| 	// arm64:-`.*runtime[.]gcWriteBarrier`
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| 	p[1] = b
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| 	// amd64:-`.*runtime[.]gcWriteBarrier`
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| 	// arm64:-`.*runtime[.]gcWriteBarrier`
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| 	p[2] = c
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| 	// amd64:-`.*runtime[.]gcWriteBarrier`
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| 	// arm64:-`.*runtime[.]gcWriteBarrier`
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| 	p[3] = d
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| }
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| 
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| func combine2slice(p *[2][]byte, a, b []byte) {
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| 	// amd64:`.*runtime[.]gcWriteBarrier4\(SB\)`
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| 	// arm64:`.*runtime[.]gcWriteBarrier4\(SB\)`
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| 	p[0] = a
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| 	// amd64:-`.*runtime[.]gcWriteBarrier`
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| 	// arm64:-`.*runtime[.]gcWriteBarrier`
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| 	p[1] = b
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| }
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| 
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| func combine4slice(p *[4][]byte, a, b, c, d []byte) {
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| 	// amd64:`.*runtime[.]gcWriteBarrier8\(SB\)`
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| 	// arm64:`.*runtime[.]gcWriteBarrier8\(SB\)`
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| 	p[0] = a
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| 	// amd64:-`.*runtime[.]gcWriteBarrier`
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| 	// arm64:-`.*runtime[.]gcWriteBarrier`
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| 	p[1] = b
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| 	// amd64:-`.*runtime[.]gcWriteBarrier`
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| 	// arm64:-`.*runtime[.]gcWriteBarrier`
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| 	p[2] = c
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| 	// amd64:-`.*runtime[.]gcWriteBarrier`
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| 	// arm64:-`.*runtime[.]gcWriteBarrier`
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| 	p[3] = d
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| }
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| 
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| func trickyWriteNil(p *int, q **int) {
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| 	if p == nil {
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| 		// We change "= p" to "= 0" in the prove pass, which
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| 		// means we have one less pointer that needs to go
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| 		// into the write barrier buffer.
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| 		// amd64:`.*runtime[.]gcWriteBarrier1`
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| 		*q = p
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| 	}
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| }
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| 
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| type S struct {
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| 	a, b string
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| 	c    *int
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| }
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| 
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| var g1, g2 *int
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| 
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| func issue71228(dst *S, ptr *int) {
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| 	// Make sure that the non-write-barrier write.
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| 	// "sp.c = ptr" happens before the large write
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| 	// barrier "*dst = *sp". We approximate testing
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| 	// that by ensuring that two global variable write
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| 	// barriers aren't combined.
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| 	_ = *dst
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| 	var s S
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| 	sp := &s
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| 	//amd64:`.*runtime[.]gcWriteBarrier1`
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| 	g1 = nil
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| 	sp.c = ptr // outside of any write barrier
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| 	//amd64:`.*runtime[.]gcWriteBarrier1`
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| 	g2 = nil
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| 	//amd64:`.*runtime[.]wbMove`
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| 	*dst = *sp
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| }
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| 
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| func writeDouble(p *[2]*int, x, y *int) {
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| 	// arm64: `LDP\s`, `STP\s\(R[0-9]+, R[0-9]+\), \(`,
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| 	p[0] = x
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| 	// arm64: `STP\s\(R[0-9]+, R[0-9]+\), 16\(`,
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| 	p[1] = y
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| }
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| 
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| func writeDoubleNil(p *[2]*int) {
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| 	// arm64: `LDP\s`, `STP\s\(R[0-9]+, R[0-9]+\),`, `STP\s\(ZR, ZR\),`
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| 	p[0] = nil
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| 	p[1] = nil
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| }
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