From ccd992355df7192993c666236047820244914598 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Tue, 16 Apr 2024 21:19:13 +0200 Subject: Adding upstream version 1.21.8. Signed-off-by: Daniel Baumann --- test/fixedbugs/bug484.go | 78 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 test/fixedbugs/bug484.go (limited to 'test/fixedbugs/bug484.go') diff --git a/test/fixedbugs/bug484.go b/test/fixedbugs/bug484.go new file mode 100644 index 0000000..bd4fa51 --- /dev/null +++ b/test/fixedbugs/bug484.go @@ -0,0 +1,78 @@ +// run + +// Copyright 2014 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. + +// The liveness code used to say that, in func g, s was live +// starting at its declaration, because it appears to have its +// address taken by the closure (different s, but the parser +// gets slightly confused, a separate bug). The liveness analysis +// saw s as having its address taken but the register optimizer +// did not. This mismatch meant that s would be marked live +// (and therefore initialized) at the call to f, but the register optimizer +// would optimize away the initialization of s before f, causing the +// garbage collector to use unused data. +// The register optimizer has been changed to respect the +// same "address taken" flag that the liveness analysis uses, +// even if it cannot see any address being taken in the actual +// machine code. This is conservative but keeps the two consistent, +// which is the most important thing. + +package main + +import "runtime" + +//go:noinline +func f() interface{} { + runtime.GC() + return nil +} + +//go:noinline +func g() { + var s interface{} + _ = func() { + s := f() + _ = s + } + s = f() + useiface(s) + useiface(s) +} + +//go:noinline +func useiface(x interface{}) { +} + +//go:noinline +func h() { + var x [16]uintptr + for i := range x { + x[i] = 1 + } + + useint(x[0]) + useint(x[1]) + useint(x[2]) + useint(x[3]) +} + +//go:noinline +func useint(x uintptr) { +} + +func main() { + // scribble non-zero values on stack + h() + // call function that used to let the garbage collector + // see uninitialized stack values; it will see the + // nonzero values. + g() +} + +func big(x int) { + if x >= 0 { + big(x - 1) + } +} -- cgit v1.2.3