From 298720d324fc8ad041b3b9d9bb9a80982ee53ced Mon Sep 17 00:00:00 2001
From: David Blaikie <dblaikie@gmail.com>
Date: Wed, 28 Jan 2015 19:50:09 +0000
Subject: [PATCH] DebugInfo: Attribute implicit boolean tests to the expression
 being tested, not to the outer use of that expression.

This is half a fix for a GDB test suite failure that expects to start at
'a' in the following code:

  void func(int a)
    if (a
        &&
	b)
	...

But instead, without this change, the comparison was assigned to '&&'
(well, worse actually - because there was a chained 'a && b && c' and it
was assigned to the second '&&' because of a recursive application of
this bug) and then the load folded into the comparison so breaking on
the function started at '&&' instead of 'a'.

The other part of this needs to be fixed in LLVM where it's ignoring the
location of the icmp and instead using the location of the branch
instruction.

The fix to the conditional operator is actually a no-op currently,
because the conditional operator's location coincides with 'a' (the
start of the conditional expression) but should probably be '?' instead.
See the FIXME in the test case that mentions the ARCMigration tool
failures when I tried to make that change.

llvm-svn: 227356
---
 clang/lib/CodeGen/CGDebugInfo.h           |  2 ++
 clang/lib/CodeGen/CodeGenFunction.cpp     | 21 +++++++++++-----
 clang/test/CodeGenCXX/debug-info-line.cpp | 42 +++++++++++++++++++++++++++++++
 3 files changed, 59 insertions(+), 6 deletions(-)

diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 962ae8b..e16dbc37 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -443,6 +443,8 @@ private:
   }
 };
 
+/// A scoped helper to set the current debug location to the specified location
+/// or preferred location of the specified Expr.
 class ApplyDebugLocation {
 private:
   void init(SourceLocation TemporaryLocation);
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index d08e011..ae78aa0 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1058,8 +1058,11 @@ void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
       uint64_t RHSCount = Cnt.getCount();
 
       ConditionalEvaluation eval(*this);
-      EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock, RHSCount);
-      EmitBlock(LHSTrue);
+      {
+        ApplyDebugLocation DL(*this, Cond);
+        EmitBranchOnBoolExpr(CondBOp->getLHS(), LHSTrue, FalseBlock, RHSCount);
+        EmitBlock(LHSTrue);
+      }
 
       // Any temporaries created here are conditional.
       Cnt.beginRegion(Builder);
@@ -1103,8 +1106,11 @@ void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
       uint64_t RHSCount = TrueCount - LHSCount;
 
       ConditionalEvaluation eval(*this);
-      EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse, LHSCount);
-      EmitBlock(LHSFalse);
+      {
+        ApplyDebugLocation DL(*this, Cond);
+        EmitBranchOnBoolExpr(CondBOp->getLHS(), TrueBlock, LHSFalse, LHSCount);
+        EmitBlock(LHSFalse);
+      }
 
       // Any temporaries created here are conditional.
       Cnt.beginRegion(Builder);
@@ -1151,8 +1157,11 @@ void CodeGenFunction::EmitBranchOnBoolExpr(const Expr *Cond,
     cond.begin(*this);
     EmitBlock(LHSBlock);
     Cnt.beginRegion(Builder);
-    EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock,
-                         LHSScaledTrueCount);
+    {
+      ApplyDebugLocation DL(*this, Cond);
+      EmitBranchOnBoolExpr(CondOp->getLHS(), TrueBlock, FalseBlock,
+                           LHSScaledTrueCount);
+    }
     cond.end(*this);
 
     cond.begin(*this);
diff --git a/clang/test/CodeGenCXX/debug-info-line.cpp b/clang/test/CodeGenCXX/debug-info-line.cpp
index a23c242..af78f23 100644
--- a/clang/test/CodeGenCXX/debug-info-line.cpp
+++ b/clang/test/CodeGenCXX/debug-info-line.cpp
@@ -213,6 +213,43 @@ void f17(int *x) {
       x[1];
 }
 
+// CHECK-LABEL: define
+void f18(int a, int b) {
+// CHECK: icmp {{.*}}, !dbg [[DBG_F18_1:![0-9]*]]
+// CHECK: br {{.*}}, !dbg [[DBG_F18_2:![0-9]*]]
+#line 2000
+  if (a  //
+      && //
+      b)
+    ;
+}
+
+// CHECK-LABEL: define
+void f19(int a, int b) {
+// CHECK: icmp {{.*}}, !dbg [[DBG_F19_1:![0-9]*]]
+// CHECK: br {{.*}}, !dbg [[DBG_F19_2:![0-9]*]]
+#line 2100
+  if (a  //
+      || //
+      b)
+    ;
+}
+
+// CHECK-LABEL: define
+void f20(int a, int b, int c) {
+// CHECK: icmp {{.*}}, !dbg [[DBG_F20_1:![0-9]*]]
+// FIXME: Conditional operator's exprloc should be the '?' not the start of the
+// expression, then this would go in the right place. (but adding getExprLoc to
+// the ConditionalOperator breaks the ARC migration tool - need to investigate
+// further).
+// CHECK: br {{.*}}, !dbg [[DBG_F20_1]]
+#line 2200
+  if (a  //
+      ? //
+      b : c)
+    ;
+}
+
 // CHECK: [[DBG_F1]] = !MDLocation(line: 100,
 // CHECK: [[DBG_FOO_VALUE]] = !MDLocation(line: 200,
 // CHECK: [[DBG_FOO_REF]] = !MDLocation(line: 202,
@@ -236,3 +273,8 @@ void f17(int *x) {
 // CHECK: [[DBG_F15]] = !MDLocation(line: 1700,
 // CHECK: [[DBG_F16]] = !MDLocation(line: 1800,
 // CHECK: [[DBG_F17]] = !MDLocation(line: 1900,
+// CHECK: [[DBG_F18_1]] = !MDLocation(line: 2000,
+// CHECK: [[DBG_F18_2]] = !MDLocation(line: 2001,
+// CHECK: [[DBG_F19_1]] = !MDLocation(line: 2100,
+// CHECK: [[DBG_F19_2]] = !MDLocation(line: 2101,
+// CHECK: [[DBG_F20_1]] = !MDLocation(line: 2200,
-- 
2.7.4