| From e66f895667cd51d0d28c42d369a803c12db8bb35 Mon Sep 17 00:00:00 2001 |
| From: Alex Brachet <abrachet@google.com> |
| Date: Thu, 19 May 2022 16:58:46 +0000 |
| Subject: [PATCH] cmd/cgo: allow DW_TAG_variable's with no name |
| |
| https://reviews.llvm.org/D123534 is emitting DW_TAG_variable's |
| that don't have a DW_AT_name. This is allowed in the DWARF |
| standard. It is adding DIE's for string literals for better |
| symbolization on buffer overlows etc on these strings. They |
| no associated name because they are not user provided variables. |
| |
| Fixes #53000 |
| |
| Change-Id: I2cf063160508687067c7672cef0517bccd707d7b |
| Reviewed-on: https://go-review.googlesource.com/c/go/+/406816 |
| TryBot-Result: Gopher Robot <gobot@golang.org> |
| Run-TryBot: Ian Lance Taylor <iant@google.com> |
| Auto-Submit: Ian Lance Taylor <iant@google.com> |
| Reviewed-by: Ian Lance Taylor <iant@google.com> |
| --- |
| |
| diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go |
| index 855309e..4d1a5bd 100644 |
| --- a/src/cmd/cgo/gcc.go |
| +++ b/src/cmd/cgo/gcc.go |
| @@ -576,8 +576,23 @@ |
| switch e.Tag { |
| case dwarf.TagVariable: |
| name, _ := e.Val(dwarf.AttrName).(string) |
| + // As of https://reviews.llvm.org/D123534, clang |
| + // now emits DW_TAG_variable DIEs that have |
| + // no name (so as to be able to describe the |
| + // type and source locations of constant strings |
| + // like the second arg in the call below: |
| + // |
| + // myfunction(42, "foo") |
| + // |
| + // If a var has no name we won't see attempts to |
| + // refer to it via "C.<name>", so skip these vars |
| + // |
| + // See issue 53000 for more context. |
| + if name == "" { |
| + break |
| + } |
| typOff, _ := e.Val(dwarf.AttrType).(dwarf.Offset) |
| - if name == "" || typOff == 0 { |
| + if typOff == 0 { |
| if e.Val(dwarf.AttrSpecification) != nil { |
| // Since we are reading all the DWARF, |
| // assume we will see the variable elsewhere. |
