New -fcatch-undefined-behavior features:

 * when checking that a pointer or reference refers to appropriate storage for a type, also check the alignment and perform a null check
 * check that references are bound to appropriate storage
 * check that 'this' has appropriate storage in member accesses and member function calls

llvm-svn: 162523

2 files changed, 75 insertions, 3 deletions

diff --git a/clang/test/CodeGen/catch-undef-behavior.c b/clang/test/CodeGen/catch-undef-behavior.c
index ee0b6586dd8..8c45fa50456 100644
--- a/clang/test/CodeGen/catch-undef-behavior.c
+++ b/clang/test/CodeGen/catch-undef-behavior.c
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fcatch-undefined-behavior -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -fcatch-undefined-behavior -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s
 
 // PR6805
 // CHECK: @foo
@@ -11,7 +11,11 @@ void foo() {
 
 // CHECK: @bar
 int bar(int *a) {
-  // CHECK: objectsize
-  // CHECK: icmp uge
+  // CHECK: %[[SIZE:.*]] = call i64 @llvm.objectsize.i64
+  // CHECK-NEXT: icmp uge i64 %[[SIZE]], 4
+
+  // CHECK: %[[PTRINT:.*]] = ptrtoint
+  // CHECK-NEXT: %[[MISALIGN:.*]] = and i64 %[[PTRINT]], 3
+  // CHECK-NEXT: icmp eq i64 %[[MISALIGN]], 0
   return *a;
 }
diff --git a/clang/test/CodeGenCXX/catch-undef-behavior.cpp b/clang/test/CodeGenCXX/catch-undef-behavior.cpp
new file mode 100644
index 00000000000..ed0a7763f51
--- /dev/null
+++ b/clang/test/CodeGenCXX/catch-undef-behavior.cpp
@@ -0,0 +1,68 @@
+// RUN: %clang_cc1 -fcatch-undefined-behavior -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s
+
+// CHECK: @_Z17reference_binding
+void reference_binding(int *p) {
+  // C++ core issue 453: If an lvalue to which a reference is directly bound
+  // designates neither an existing object or function of an appropriate type,
+  // nor a region of storage of suitable size and alignment to contain an object
+  // of the reference's type, the behavior is undefined.
+
+  // CHECK: icmp ne {{.*}}, null
+
+  // CHECK: %[[SIZE:.*]] = call i64 @llvm.objectsize.i64
+  // CHECK-NEXT: icmp uge i64 %[[SIZE]], 4
+
+  // CHECK: %[[PTRINT:.*]] = ptrtoint
+  // CHECK-NEXT: %[[MISALIGN:.*]] = and i64 %[[PTRINT]], 3
+  // CHECK-NEXT: icmp eq i64 %[[MISALIGN]], 0
+  int &r = *p;
+}
+
+struct S {
+  double d;
+  int a, b;
+  virtual int f();
+};
+
+// CHECK: @_Z13member_access
+void member_access(S *p) {
+  // (1) Check 'p' is appropriately sized and aligned for member access.
+
+  // FIXME: Check vptr is for 'S' or a class derived from 'S'.
+
+  // CHECK: icmp ne {{.*}}, null
+
+  // CHECK: %[[SIZE:.*]] = call i64 @llvm.objectsize.i64
+  // CHECK-NEXT: icmp uge i64 %[[SIZE]], 24
+
+  // CHECK: %[[PTRINT:.*]] = ptrtoint
+  // CHECK-NEXT: %[[MISALIGN:.*]] = and i64 %[[PTRINT]], 7
+  // CHECK-NEXT: icmp eq i64 %[[MISALIGN]], 0
+
+  // (2) Check 'p->b' is appropriately sized and aligned for a load.
+
+  // FIXME: Suppress this in the trivial case of a member access, because we
+  // know we've just checked the member access expression itself.
+
+  // CHECK: %[[SIZE:.*]] = call i64 @llvm.objectsize.i64
+  // CHECK-NEXT: icmp uge i64 %[[SIZE]], 4
+
+  // CHECK: %[[PTRINT:.*]] = ptrtoint
+  // CHECK-NEXT: %[[MISALIGN:.*]] = and i64 %[[PTRINT]], 3
+  // CHECK-NEXT: icmp eq i64 %[[MISALIGN]], 0
+  int k = p->b;
+
+  // (3) Check 'p' is appropriately sized and aligned for member function call.
+
+  // FIXME: Check vptr is for 'S' or a class derived from 'S'.
+
+  // CHECK: icmp ne {{.*}}, null
+
+  // CHECK: %[[SIZE:.*]] = call i64 @llvm.objectsize.i64
+  // CHECK-NEXT: icmp uge i64 %[[SIZE]], 24
+
+  // CHECK: %[[PTRINT:.*]] = ptrtoint
+  // CHECK-NEXT: %[[MISALIGN:.*]] = and i64 %[[PTRINT]], 7
+  // CHECK-NEXT: icmp eq i64 %[[MISALIGN]], 0
+  k = p->f();
+}