carbon-language/carbon-lang
1
0
Fork 0
mirror of https://github.com/carbon-language/carbon-lang.git synced 2026-10-05 12:21:06 +01:00
Code Issues Packages Projects Releases 10 Wiki Activity

Give thunks weak_odr linkage. (#7525)

Browse Source 
We can end up emitting the same thunk from multiple compilations in some
cases -- in particular, when the thunk is wrapping a function that is
either synthesized by the compiler or imported from C++. When this
happens, we will have multiple-definition link errors unless we allow
redefinitions across multiple files.

It'd be nice to detect when we need to do this and when we don't, but
that's a bit tricky to do in practice. Ideally, in fact, we would use a
different strategy, and emit the thunks as discardable definitions in
each compilation that *uses* them. But for now emitting them with
weak_odr linkage seems like a good way to make progress.
This commit is contained in:
Richard Smith
2026-07-17 13:25:19 +00:00
committed by GitHub
parent 643ab57f5a
commit 5c544f7c2f
20 changed files with 362 additions and 75 deletions
Download Patch File Download Diff File Expand all files Collapse all files
toolchain/lower/testdata/interop/cpp/class/export/method.carbon
Vendored
+3 -3
View File
@@ -117,7 +117,7 @@ fn CallCallF() { Cpp.CallF(); }
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.A.Main"(ptr %self) #5 !dbg !22 {
// CHECK:STDOUT: define weak_odr void @"_C__destroy_thunk:thunk.A.Main"(ptr %self) #5 !dbg !22 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: call void @"_COp.68011419f123494e:core.Destroy.Core"(ptr %self), !dbg !25
// CHECK:STDOUT: ret void, !dbg !25
@@ -240,7 +240,7 @@ fn CallCallF() { Cpp.CallF(); }
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.A.Main"(ptr %self) #5 !dbg !25 {
// CHECK:STDOUT: define weak_odr void @"_C__destroy_thunk:thunk.A.Main"(ptr %self) #5 !dbg !25 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: call void @"_COp.68011419f123494e:core.Destroy.Core"(ptr %self), !dbg !30
// CHECK:STDOUT: ret void, !dbg !30
@@ -355,7 +355,7 @@ fn CallCallF() { Cpp.CallF(); }
// CHECK:STDOUT: }
// CHECK:STDOUT:
// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.A.Main"(ptr %self) #3 !dbg !16 {
// CHECK:STDOUT: define weak_odr void @"_C__destroy_thunk:thunk.A.Main"(ptr %self) #3 !dbg !16 {
// CHECK:STDOUT: entry:
// CHECK:STDOUT: call void @"_COp.68011419f123494e:core.Destroy.Core"(ptr %self), !dbg !22
// CHECK:STDOUT: ret void, !dbg !22