Fix for PR33930. Short-circuit metadata mapping when cloning a varargs thunk.
The cloning happens before all metadata nodes are resolved. Prevent the value
mapper from running into unresolved or temporary MD nodes.
Differential Revision: https://reviews.llvm.org/D39396
llvm-svn: 317047
diff --git a/clang/lib/CodeGen/CGVTables.cpp b/clang/lib/CodeGen/CGVTables.cpp
index 64b6d0d..67388ee 100644
--- a/clang/lib/CodeGen/CGVTables.cpp
+++ b/clang/lib/CodeGen/CGVTables.cpp
@@ -14,11 +14,12 @@
#include "CGCXXABI.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
-#include "clang/CodeGen/ConstantInitBuilder.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/RecordLayout.h"
#include "clang/CodeGen/CGFunctionInfo.h"
+#include "clang/CodeGen/ConstantInitBuilder.h"
#include "clang/Frontend/CodeGenOptions.h"
+#include "llvm/IR/IntrinsicInst.h"
#include "llvm/Support/Format.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include <algorithm>
@@ -122,6 +123,33 @@
return RValue::get(ReturnValue);
}
+/// This function clones a function's DISubprogram node and enters it into
+/// a value map with the intent that the map can be utilized by the cloner
+/// to short-circuit Metadata node mapping.
+/// Furthermore, the function resolves any DILocalVariable nodes referenced
+/// by dbg.value intrinsics so they can be properly mapped during cloning.
+static void resolveTopLevelMetadata(llvm::Function *Fn,
+ llvm::ValueToValueMapTy &VMap) {
+ // Clone the DISubprogram node and put it into the Value map.
+ auto *DIS = Fn->getSubprogram();
+ if (!DIS)
+ return;
+ auto *NewDIS = DIS->replaceWithDistinct(DIS->clone());
+ VMap.MD()[DIS].reset(NewDIS);
+
+ // Find all llvm.dbg.declare intrinsics and resolve the DILocalVariable nodes
+ // they are referencing.
+ for (auto &BB : Fn->getBasicBlockList()) {
+ for (auto &I : BB) {
+ if (auto *DII = dyn_cast<llvm::DbgInfoIntrinsic>(&I)) {
+ auto *DILocal = DII->getVariable();
+ if (!DILocal->isResolved())
+ DILocal->resolve();
+ }
+ }
+ }
+}
+
// This function does roughly the same thing as GenerateThunk, but in a
// very different way, so that va_start and va_end work correctly.
// FIXME: This function assumes "this" is the first non-sret LLVM argument of
@@ -154,6 +182,10 @@
// Clone to thunk.
llvm::ValueToValueMapTy VMap;
+
+ // We are cloning a function while some Metadata nodes are still unresolved.
+ // Ensure that the value mapper does not encounter any of them.
+ resolveTopLevelMetadata(BaseFn, VMap);
llvm::Function *NewFn = llvm::CloneFunction(BaseFn, VMap);
Fn->replaceAllUsesWith(NewFn);
NewFn->takeName(Fn);