[llgo] debug: create replaceable type through DIBuilder

Summary:
llgo was asserting in DebugInfo, which was interpreting
the temporary MDNodes we were creating as DIScopes instead
of DITypes (in DIScope::getRef).

This proposal changes llgo to use DIBuilder's
createReplaceableCompositeType method to create a DIType
that can be RAUW'd.

Reviewers: pcc

Reviewed By: pcc

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7852

llvm-svn: 230953

diff --git a/llgo/debug/debug.go b/llgo/debug/debug.go
index d470655..b8c6bf6 100644 (file)
--- a/llgo/debug/debug.go
+++ b/llgo/debug/debug.go
@@ -340,18 +340,26 @@ func (d *DIBuilder) descriptorStruct(t *types.Struct, name string) llvm.Metadata
 }
 
 func (d *DIBuilder) descriptorNamed(t *types.Named) llvm.Metadata {
-       // Create a placeholder for the named type, to terminate cycles.
-       placeholder := llvm.GlobalContext().TemporaryMDNode(nil)
-       d.types.Set(t, placeholder)
        var diFile llvm.Metadata
        var line int
        if file := d.fset.File(t.Obj().Pos()); file != nil {
                line = file.Line(t.Obj().Pos())
                diFile = d.getFile(file)
        }
+
+       // Create a placeholder for the named type, to terminate cycles.
+       name := t.Obj().Name()
+       placeholder := d.builder.CreateReplaceableCompositeType(d.scope(), llvm.DIReplaceableCompositeType{
+               Tag:  dwarf.TagStructType,
+               Name: name,
+               File: diFile,
+               Line: line,
+       })
+       d.types.Set(t, placeholder)
+
        typedef := d.builder.CreateTypedef(llvm.DITypedef{
                Type: d.DIType(t.Underlying()),
-               Name: t.Obj().Name(),
+               Name: name,
                File: diFile,
                Line: line,
        })