From: Peter Collingbourne <peter@pcc.me.uk>
Date: Thu, 14 Jan 2016 02:49:48 +0000 (+0000)
Subject: CodeGen: Only emit CFI unrelated cast checks for bit casts.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=837aba93a3f7adda45262dbfad3dd4f39b9fc08a;p=clang

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).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@257738 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 507ce3d7d0..e918cd81f0 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -824,7 +824,8 @@ Address CodeGenFunction::EmitPointerWithAlignment(const Expr *E,
                          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,
diff --git a/test/CodeGenCXX/cfi-cast.cpp b/test/CodeGenCXX/cfi-cast.cpp
index 0b96cb6506..845b9553b2 100644
--- a/test/CodeGenCXX/cfi-cast.cpp
+++ b/test/CodeGenCXX/cfi-cast.cpp
@@ -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();
+}