Fix 2 cases of uninitialized reads of an invalid PresumedLoc.

The code in CGExpr was added back in 2012 (r165536) but not exercised in tests
until recently.

Detected on the MemorySanitizer bootstrap bot.

llvm-svn: 190521

2 files changed, 17 insertions, 15 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 12aa0a2b7c4..89340b4db82 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -2095,8 +2095,8 @@ llvm::Constant *CodeGenFunction::EmitCheckSourceLocation(SourceLocation Loc) {
     PLoc.isValid() ? cast<llvm::Constant>(
                        Builder.CreateGlobalStringPtr(PLoc.getFilename()))
                    : llvm::Constant::getNullValue(Int8PtrTy),
-    Builder.getInt32(PLoc.getLine()),
-    Builder.getInt32(PLoc.getColumn())
+    Builder.getInt32(PLoc.isValid() ? PLoc.getLine() : 0),
+    Builder.getInt32(PLoc.isValid() ? PLoc.getColumn() : 0)
   };
 
   return llvm::ConstantStruct::getAnon(Data);
diff --git a/clang/tools/libclang/CXSourceLocation.cpp b/clang/tools/libclang/CXSourceLocation.cpp
index a33c9d4f269..64b2908c49d 100644
--- a/clang/tools/libclang/CXSourceLocation.cpp
+++ b/clang/tools/libclang/CXSourceLocation.cpp
@@ -266,7 +266,7 @@ void clang_getPresumedLocation(CXSourceLocation location,
                                CXString *filename,
                                unsigned *line,
                                unsigned *column) {
-  
+
   if (!isASTUnitSourceLocation(location)) {
     // Other SourceLocation implementations do not support presumed locations
     // at this time.
@@ -276,20 +276,22 @@ void clang_getPresumedLocation(CXSourceLocation location,
 
   SourceLocation Loc = SourceLocation::getFromRawEncoding(location.int_data);
 
-  if (!location.ptr_data[0] || Loc.isInvalid())
+  if (!location.ptr_data[0] || Loc.isInvalid()) {
     createNullLocation(filename, line, column);
-  else {
-    const SourceManager &SM =
-    *static_cast<const SourceManager*>(location.ptr_data[0]);
-    PresumedLoc PreLoc = SM.getPresumedLoc(Loc);
-    
-    if (filename)
-      *filename = cxstring::createRef(PreLoc.getFilename());
-    if (line)
-      *line = PreLoc.getLine();
-    if (column)
-      *column = PreLoc.getColumn();
+    return;
   }
+
+  const SourceManager &SM =
+      *static_cast<const SourceManager *>(location.ptr_data[0]);
+  PresumedLoc PreLoc = SM.getPresumedLoc(Loc);
+  if (PreLoc.isInvalid()) {
+    createNullLocation(filename, line, column);
+    return;
+  }
+
+  if (filename) *filename = cxstring::createRef(PreLoc.getFilename());
+  if (line) *line = PreLoc.getLine();
+  if (column) *column = PreLoc.getColumn();
 }
 
 void clang_getInstantiationLocation(CXSourceLocation location,