Fix a couple of wrong-code bugs in switch-on-constant optimization:

 * recurse through intermediate LabelStmts and AttributedStmts when checking
   whether a statement inside a switch declares a variable
 * if the end of a compound statement is reachable from the chosen case label,
   and the compound statement contains a variable declaration, it's not valid
   to just emit the contents of the compound statement -- we must emit the
   statement itself or we lose the scope (and thus end lifetimes at the wrong
   point)

llvm-svn: 281797

1 files changed, 23 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 0b9fe29a9ce..1959f468318 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -25,6 +25,7 @@
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/StmtCXX.h"
+#include "clang/AST/StmtObjC.h"
 #include "clang/Basic/Builtins.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/CodeGen/CGFunctionInfo.h"
@@ -1168,6 +1169,28 @@ bool CodeGenFunction::containsBreak(const Stmt *S) {
   return false;
 }
 
+bool CodeGenFunction::mightAddDeclToScope(const Stmt *S) {
+  if (!S) return false;
+
+  // Some statement kinds add a scope and thus never add a decl to the current
+  // scope. Note, this list is longer than the list of statements that might
+  // have an unscoped decl nested within them, but this way is conservatively
+  // correct even if more statement kinds are added.
+  if (isa<IfStmt>(S) || isa<SwitchStmt>(S) || isa<WhileStmt>(S) ||
+      isa<DoStmt>(S) || isa<ForStmt>(S) || isa<CompoundStmt>(S) ||
+      isa<CXXForRangeStmt>(S) || isa<CXXTryStmt>(S) ||
+      isa<ObjCForCollectionStmt>(S) || isa<ObjCAtTryStmt>(S))
+    return false;
+
+  if (isa<DeclStmt>(S))
+    return true;
+
+  for (const Stmt *SubStmt : S->children())
+    if (mightAddDeclToScope(SubStmt))
+      return true;
+
+  return false;
+}
 
 /// ConstantFoldsToSimpleInteger - If the specified expression does not fold
 /// to a constant, or if it does but contains a label, return false.  If it