Fix the dtor location issues in PR20038 harder.

Originally committed in r211722, this fixed one case of dtor calls being
emitted without locations (this causes problems for debug info if the
call is then inlined), this caught only some of the cases.

Instead of trying to re-enable the location before the cleanup, simply
re-enable the location immediately after the unconditional branches in
question using a scoped device to ensure the no-location state doesn't
leak out arbitrarily.

llvm-svn: 212761

Author: dwblaikie

clang/lib/CodeGen/CGExprScalar.cpp

@@ -358,10 +358,7 @@ class ScalarExprEmitter
   Value *VisitExprWithCleanups(ExprWithCleanups *E) {
     CGF.enterFullExpression(E);
     CodeGenFunction::RunCleanupsScope Scope(CGF);
-    auto *V = Visit(E->getSubExpr());
-    if (CGDebugInfo *DI = CGF.getDebugInfo())
-      DI->EmitLocation(Builder, E->getLocEnd(), false);
-    return V;
+    return Visit(E->getSubExpr());
   }
   Value *VisitCXXNewExpr(const CXXNewExpr *E) {
     return CGF.EmitCXXNewExpr(E);
@@ -2942,12 +2939,13 @@ Value *ScalarExprEmitter::VisitBinLAnd(const BinaryOperator *E) {
   // Reaquire the RHS block, as there may be subblocks inserted.
   RHSBlock = Builder.GetInsertBlock();
 
-  // Emit an unconditional branch from this block to ContBlock.  Insert an entry
-  // into the phi node for the edge with the value of RHSCond.
-  if (CGF.getDebugInfo())
+  // Emit an unconditional branch from this block to ContBlock.
+  {
     // There is no need to emit line number for unconditional branch.
-    Builder.SetCurrentDebugLocation(llvm::DebugLoc());
-  CGF.EmitBlock(ContBlock);
+    SuppressDebugLocation S(Builder);
+    CGF.EmitBlock(ContBlock);
+  }
+  // Insert an entry into the phi node for the edge with the value of RHSCond.
   PN->addIncoming(RHSCond, RHSBlock);
 
   // ZExt result to int.

clang/lib/CodeGen/CGStmt.cpp

@@ -524,18 +524,20 @@ void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
 
   // Emit the 'else' code if present.
   if (const Stmt *Else = S.getElse()) {
-    // There is no need to emit line number for unconditional branch.
-    if (getDebugInfo())
-      Builder.SetCurrentDebugLocation(llvm::DebugLoc());
-    EmitBlock(ElseBlock);
+    {
+      // There is no need to emit line number for unconditional branch.
+      SuppressDebugLocation S(Builder);
+      EmitBlock(ElseBlock);
+    }
     {
       RunCleanupsScope ElseScope(*this);
       EmitStmt(Else);
     }
-    // There is no need to emit line number for unconditional branch.
-    if (getDebugInfo())
-      Builder.SetCurrentDebugLocation(llvm::DebugLoc());
-    EmitBranch(ContBlock);
+    {
+      // There is no need to emit line number for unconditional branch.
+      SuppressDebugLocation S(Builder);
+      EmitBranch(ContBlock);
+    }
   }
 
   // Emit the continuation block for code after the if.

clang/lib/CodeGen/CodeGenFunction.h

@@ -93,6 +93,19 @@ enum TypeEvaluationKind {
   TEK_Aggregate
 };
 
+class SuppressDebugLocation {
+  llvm::DebugLoc CurLoc;
+  llvm::IRBuilderBase &Builder;
+public:
+  SuppressDebugLocation(llvm::IRBuilderBase &Builder)
+      : CurLoc(Builder.getCurrentDebugLocation()), Builder(Builder) {
+    Builder.SetCurrentDebugLocation(llvm::DebugLoc());
+  }
+  ~SuppressDebugLocation() {
+    Builder.SetCurrentDebugLocation(CurLoc);
+  }
+};
+
 /// CodeGenFunction - This class organizes the per-function state that is used
 /// while generating LLVM code.
 class CodeGenFunction : public CodeGenTypeCache {

clang/test/CodeGenCXX/PR20038.cpp

@@ -4,8 +4,13 @@ struct C {
   ~C();
 };
 extern bool b;
-// CHECK: call {{.*}}, !dbg [[DTOR_CALL_LOC:![0-9]*]]
-// CHECK: [[FUN4:.*]] = {{.*}}; [ DW_TAG_subprogram ] {{.*}} [def] [fun4]
-// CHECK: [[DTOR_CALL_LOC]] = metadata !{i32 [[@LINE+2]], i32 0, metadata [[FUN4_BLOCK:.*]], null}
-// CHECK: [[FUN4_BLOCK]] = metadata !{{{[^,]*}}, {{[^,]*}}, metadata [[FUN4]],
-void fun4() { b && (C(), 1); }
+// CHECK: call {{.*}}, !dbg [[DTOR_CALL1_LOC:![0-9]*]]
+// CHECK: call {{.*}}, !dbg [[DTOR_CALL2_LOC:![0-9]*]]
+// CHECK: [[FUN1:.*]] = {{.*}}; [ DW_TAG_subprogram ] {{.*}} [def] [fun1]
+// CHECK: [[FUN2:.*]] = {{.*}}; [ DW_TAG_subprogram ] {{.*}} [def] [fun2]
+// CHECK: [[DTOR_CALL1_LOC]] = metadata !{i32 [[@LINE+2]], i32 0, metadata [[FUN1_BLOCK:.*]], null}
+// CHECK: [[FUN1_BLOCK]] = metadata !{{{[^,]*}}, {{[^,]*}}, metadata [[FUN1]],
+void fun1() { b && (C(), 1); }
+// CHECK: [[DTOR_CALL2_LOC]] = metadata !{i32 [[@LINE+2]], i32 0, metadata [[FUN2_BLOCK1:.*]], null}
+// CHECK: [[FUN2_BLOCK1]] = metadata !{{{[^,]*}}, {{[^,]*}}, metadata [[FUN2]],
+bool fun2() { return (C(), b) && 0; }