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8628bf9a97
This CL resurrects the clobberdead debugging mode (CL 23924). When -clobberdead flag is set (TODO: make it GOEXPERIMENT?), the compiler inserts code that clobbers all dead stack slots that contains pointers. Mark windows syscall functions cgo_unsafe_args, as the code actually does that, by taking the address of one argument and passing it to cgocall. Change-Id: Ie09a015f4bd14ae6053cc707866e30ae509b9d6f Reviewed-on: https://go-review.googlesource.com/c/go/+/301791 Trust: Cherry Zhang <cherryyz@google.com> Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Than McIntosh <thanm@google.com>
33 lines
860 B
Go
33 lines
860 B
Go
// asmcheck -gcflags=-clobberdead
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// +build amd64
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// Copyright 2021 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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package codegen
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type T [2]*int // contain pointer, not SSA-able (so locals are not registerized)
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var p1, p2, p3 T
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func F() {
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// 3735936685 is 0xdeaddead
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// clobber x, y at entry. not clobber z (stack object).
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// amd64:`MOVL\t\$3735936685, ""\.x`, `MOVL\t\$3735936685, ""\.y`, -`MOVL\t\$3735936685, ""\.z`
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x, y, z := p1, p2, p3
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addrTaken(&z)
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// x is dead at the call (the value of x is loaded before the CALL), y is not
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// amd64:`MOVL\t\$3735936685, ""\.x`, -`MOVL\t\$3735936685, ""\.y`
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use(x)
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// amd64:`MOVL\t\$3735936685, ""\.x`, `MOVL\t\$3735936685, ""\.y`
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use(y)
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}
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//go:noinline
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func use(T) {}
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//go:noinline
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func addrTaken(*T) {}
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