r257738 - CodeGen: Only emit CFI unrelated cast checks for bit casts.

[Peter Collingbourne via cfe-commits]

Author: pcc
Date: Wed Jan 13 20:49:48 2016
New Revision: 257738

URL: http://llvm.org/viewvc/llvm-project?rev=257738&view=rev
Log:
CodeGen: Only emit CFI unrelated cast checks for bit casts.

We were previously emitting them for no-op casts (e.g. implicit casts
to const).

Modified:
    cfe/trunk/lib/CodeGen/CGExpr.cpp
    cfe/trunk/test/CodeGenCXX/cfi-cast.cpp

Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=257738&r1=257737&r2=257738&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Wed Jan 13 20:49:48 2016
@@ -824,7 +824,8 @@ Address CodeGenFunction::EmitPointerWith
                          getNaturalPointeeTypeAlignment(E->getType(), Source));
         }
 
-        if (SanOpts.has(SanitizerKind::CFIUnrelatedCast)) {
+        if (SanOpts.has(SanitizerKind::CFIUnrelatedCast) &&
+            CE->getCastKind() == CK_BitCast) {
           if (auto PT = E->getType()->getAs<PointerType>())
             EmitVTablePtrCheckForCast(PT->getPointeeType(), Addr.getPointer(),
                                       /*MayBeNull=*/true,

Modified: cfe/trunk/test/CodeGenCXX/cfi-cast.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/cfi-cast.cpp?rev=257738&r1=257737&r2=257738&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/cfi-cast.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/cfi-cast.cpp Wed Jan 13 20:49:48 2016
@@ -8,6 +8,7 @@
 
 struct A {
   virtual void f();
+  int i() const;
 };
 
 struct B : A {
@@ -103,23 +104,31 @@ void vbrr(char &&r) {
 // CHECK-UCAST-LABEL: define void @_Z3vcpPv
 // CHECK-UCAST-STRICT-LABEL: define void @_Z3vcpPv
 void vcp(void *p) {
-  // CHECK-UCAST: [[P:%[^ ]*]] = call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1A")
-  // CHECK-UCAST-STRICT: [[P:%[^ ]*]] = call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1C")
+  // CHECK-UCAST: call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1A")
+  // CHECK-UCAST-STRICT: call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1C")
   static_cast<C*>(p);
 }
 
 // CHECK-UCAST-LABEL: define void @_Z3bcpP1B
 // CHECK-UCAST-STRICT-LABEL: define void @_Z3bcpP1B
 void bcp(B *p) {
-  // CHECK-UCAST: [[P:%[^ ]*]] = call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1A")
-  // CHECK-UCAST-STRICT: [[P:%[^ ]*]] = call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1C")
+  // CHECK-UCAST: call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1A")
+  // CHECK-UCAST-STRICT: call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1C")
   (C *)p;
 }
 
 // CHECK-UCAST-LABEL: define void @_Z8bcp_callP1B
 // CHECK-UCAST-STRICT-LABEL: define void @_Z8bcp_callP1B
 void bcp_call(B *p) {
-  // CHECK-UCAST: [[P:%[^ ]*]] = call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1A")
-  // CHECK-UCAST-STRICT: [[P:%[^ ]*]] = call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1C")
+  // CHECK-UCAST: call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1A")
+  // CHECK-UCAST-STRICT: call i1 @llvm.bitset.test(i8* {{%[^ ]*}}, metadata !"_ZTS1C")
   ((C *)p)->f();
 }
+
+// CHECK-UCAST-LABEL: define i32 @_Z6a_callP1A
+// CHECK-UCAST-STRICT-LABEL: define i32 @_Z6a_callP1A
+int a_call(A *a) {
+  // CHECK-UCAST-NOT: @llvm.bitset.test
+  // CHECK-UCAST-STRICT-NOT: @llvm.bitset.test
+  return a->i();
+}