[go] cmd/link: don't create __x86.get_pc_thunk symbol if it already exists

[David Chase (Gerrit)]

David Chase submitted the change with unreviewed changes

Unreviewed changes

1 is the latest approved patch-set.
The change was submitted with unreviewed changes in the following files:

```
The name of the file: src/cmd/link/internal/x86/asm.go
Insertions: 1, Deletions: 1.

@@ -72,7 +72,7 @@
 		{"di", 7},
 	} {
 		thunkfunc := ldr.CreateSymForUpdate("__x86.get_pc_thunk."+r.name, 0)
-		if thunkfunc.Type() != 0 {
+		if t := thunkfunc.Type(); t != 0 && t != sym.SXREF && t != sym.SDYNIMPORT && t != sym.SUNDEFEXT {
 			continue // symbol already exists, probably loaded from a C object
 		}
 		thunkfunc.SetType(sym.STEXT)
```

Change information

Commit message:

cmd/link: don't create __x86.get_pc_thunk symbol if it already exists

On 386, in some build modes we need to create the __x86.get_pc_thunk
symbols, to support PC-relative addressing. In some situation
the thunk symbols may already exist, e.g. loaded from a C object
in internal linking mode. In this case, we should use the exiting
symbol instead of making a new one. The current code updates the
symbol content in place but also adds a duplicated entry to Textp,
which breaks the address sorting order.

Fixes #76815.

Change-Id: Iab11106ce592dc5219b7a0e07cfafcd270661a2f

Reviewed-on: https://go-review.googlesource.com/c/go/+/730161

Reviewed-by: David Chase <drc...@google.com>

LUCI-TryBot-Result: Go LUCI <golang...@luci-project-accounts.iam.gserviceaccount.com>

Files:

• M src/cmd/link/internal/x86/asm.go

Change size: XS

Delta: 1 file changed, 3 insertions(+), 0 deletions(-)

Branch: refs/heads/master

Submit Requirements:

• Code-Review: +2 by David Chase
• TryBots-Pass: LUCI-TryBot-Result+1 by Go LUCI

Open in Gerrit

Inspect html for hidden footers to help with email filtering. To unsubscribe visit settings.

Gerrit

Gerrit-MessageType: merged

Gerrit-Project: go

Gerrit-Branch: master

Gerrit-Change-Id: Iab11106ce592dc5219b7a0e07cfafcd270661a2f

Gerrit-Change-Number: 730161

Gerrit-PatchSet: 6

Gerrit-Owner: Cherry Mui <cher...@google.com>

Gerrit-Reviewer: Cherry Mui <cher...@google.com>

Gerrit-Reviewer: David Chase <drc...@google.com>

Gerrit-Reviewer: Go LUCI <golang...@luci-project-accounts.iam.gserviceaccount.com>

Gerrit-Reviewer: Ian Lance Taylor <ia...@golang.org>