[ubsan] Have -fsanitize=vptr emit a null check if -fsanitize=null isn't available

In r309007, I made -fsanitize=null a hard prerequisite for -fsanitize=vptr. I
did not see the need for the two checks to have separate null checking logic
for the same pointer. I expected the two checks to either always be enabled
together, or to be mutually compatible.

In the mailing list discussion re: r309007 it became clear that that isn't the
case. If a codebase is -fsanitize=vptr clean but not -fsanitize=null clean,
it's useful to have -fsanitize=vptr emit its own null check. That's what this
patch does: with it, -fsanitize=vptr can be used without -fsanitize=null.

Differential Revision: https://reviews.llvm.org/D36112

llvm-svn: 309846

4 files changed, 20 insertions, 19 deletions

diff --git a/clang/test/CodeGenCXX/catch-undef-behavior.cpp b/clang/test/CodeGenCXX/catch-undef-behavior.cpp
index d95a5370fbc..179c3341226 100644
--- a/clang/test/CodeGenCXX/catch-undef-behavior.cpp
+++ b/clang/test/CodeGenCXX/catch-undef-behavior.cpp
@@ -1,6 +1,6 @@
 // RUN: %clang_cc1 -std=c++11 -fsanitize=signed-integer-overflow,integer-divide-by-zero,float-divide-by-zero,shift-base,shift-exponent,unreachable,return,vla-bound,alignment,null,vptr,object-size,float-cast-overflow,bool,enum,array-bounds,function -fsanitize-recover=signed-integer-overflow,integer-divide-by-zero,float-divide-by-zero,shift-base,shift-exponent,vla-bound,alignment,null,vptr,object-size,float-cast-overflow,bool,enum,array-bounds,function -emit-llvm %s -o - -triple x86_64-linux-gnu | opt -instnamer -S | FileCheck %s
-// RUN: %clang_cc1 -std=c++11 -fsanitize=null,vptr,address -fsanitize-recover=null,vptr,address -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-ASAN
-// RUN: %clang_cc1 -std=c++11 -fsanitize=null,vptr -fsanitize-recover=null,vptr -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=DOWNCAST-NULL
+// RUN: %clang_cc1 -std=c++11 -fsanitize=vptr,address -fsanitize-recover=vptr,address -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-ASAN
+// RUN: %clang_cc1 -std=c++11 -fsanitize=vptr -fsanitize-recover=vptr -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=DOWNCAST-NULL
 // RUN: %clang_cc1 -std=c++11 -fsanitize=function -emit-llvm %s -o - -triple x86_64-linux-gnux32 | FileCheck %s --check-prefix=CHECK-X32
 // RUN: %clang_cc1 -std=c++11 -fsanitize=function -emit-llvm %s -o - -triple i386-linux-gnu | FileCheck %s --check-prefix=CHECK-X86
 
diff --git a/clang/test/CodeGenCXX/ubsan-type-checks.cpp b/clang/test/CodeGenCXX/ubsan-type-checks.cpp
index cc2d4d6e799..e53ab2466e7 100644
--- a/clang/test/CodeGenCXX/ubsan-type-checks.cpp
+++ b/clang/test/CodeGenCXX/ubsan-type-checks.cpp
@@ -44,17 +44,22 @@ struct Dog : Animal {
 
 // VPTR-LABEL: define void @_Z12invalid_castP3Cat
 void invalid_cast(Cat *cat = nullptr) {
-  // First, null check the pointer:
+  // If -fsanitize=null is available, we'll reuse its check:
   //
   // VPTR: [[ICMP:%.*]] = icmp ne %struct.Dog* {{.*}}, null
   // VPTR-NEXT: br i1 [[ICMP]]
   // VPTR: call void @__ubsan_handle_type_mismatch
-  //
-  // Once we're done emitting the null check, reuse the check to see if we can
-  // proceed to the vptr check:
-  //
+  // VPTR-NOT: icmp ne %struct.Dog* {{.*}}, null
   // VPTR: br i1 [[ICMP]]
   // VPTR: call void @__ubsan_handle_dynamic_type_cache_miss
+  //
+  // Fall back to the vptr sanitizer's null check when -fsanitize=null isn't
+  // available.
+  //
+  // VPTR_NO_NULL-NOT: call void @__ubsan_handle_type_mismatch
+  // VPTR_NO_NULL: [[ICMP:%.*]] = icmp ne %struct.Dog* {{.*}}, null
+  // VPTR_NO_NULL-NEXT: br i1 [[ICMP]]
+  // VPTR_NO_NULL: call void @__ubsan_handle_dynamic_type_cache_miss
   auto *badDog = reinterpret_cast<Dog *>(cat);
   badDog->speak();
 }
diff --git a/clang/test/Driver/fsanitize.c b/clang/test/Driver/fsanitize.c
index 32180797013..0aa289b50b3 100644
--- a/clang/test/Driver/fsanitize.c
+++ b/clang/test/Driver/fsanitize.c
@@ -58,10 +58,6 @@
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -fno-rtti %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-NO-RTTI
 // CHECK-UNDEFINED-NO-RTTI-NOT: vptr
 
-// RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -fno-sanitize=null %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-NO-NULL
-// RUN: %clang -target x86_64-linux-gnu -fsanitize=vptr %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-NO-NULL
-// CHECK-VPTR-NO-NULL: warning: implicitly disabling vptr sanitizer because null checking wasn't enabled
-
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address,thread -fno-rtti %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANA-SANT
 // CHECK-SANA-SANT: '-fsanitize=address' not allowed with '-fsanitize=thread'
 
@@ -366,8 +362,8 @@
 // RUN: %clang -target x86_64-apple-darwin10 -mmacosx-version-min=10.8 -fsanitize=vptr %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-DARWIN-OLD
 // CHECK-VPTR-DARWIN-OLD: unsupported option '-fsanitize=vptr' for target 'x86_64-apple-darwin10'
 
-// RUN: %clang -target x86_64-apple-darwin10 -mmacosx-version-min=10.9 -fsanitize=alignment,null,vptr %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-DARWIN-NEW
-// CHECK-VPTR-DARWIN-NEW: -fsanitize=alignment,null,vptr
+// RUN: %clang -target x86_64-apple-darwin10 -mmacosx-version-min=10.9 -fsanitize=alignment,vptr %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-DARWIN-NEW
+// CHECK-VPTR-DARWIN-NEW: -fsanitize=alignment,vptr
 
 // RUN: %clang -target armv7-apple-ios7 -miphoneos-version-min=7.0 -fsanitize=address %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-IOS
 // CHECK-ASAN-IOS: -fsanitize=address
diff --git a/clang/test/Driver/rtti-options.cpp b/clang/test/Driver/rtti-options.cpp
index e7b0ff48a94..bb2958d845b 100644
--- a/clang/test/Driver/rtti-options.cpp
+++ b/clang/test/Driver/rtti-options.cpp
@@ -16,14 +16,14 @@
 // Make sure we only error/warn once, when trying to enable vptr and
 // undefined and have -fno-rtti
 // RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=undefined -fsanitize=vptr -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR -check-prefix=CHECK-OK %s
-// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=null,vptr %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
-// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=null,vptr -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
-// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=null,vptr -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR %s
+// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=vptr %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=vptr -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=vptr -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR %s
 // RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=undefined %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
 // RUN: %clang -### -c -target x86_64-unknown-linux -fsanitize=undefined -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
-// RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=null,vptr %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-WARN %s
-// RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=null,vptr -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
-// RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=null,vptr -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR %s
+// RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=vptr %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-WARN %s
+// RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=vptr -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
+// RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=vptr -fno-rtti %s 2>&1 | FileCheck -check-prefix=CHECK-SAN-ERROR %s
 // RUN: %clang -### -c -target x86_64-scei-ps4 -fsanitize=undefined -frtti %s 2>&1 | FileCheck -check-prefix=CHECK-OK %s
 
 // Exceptions + no/default rtti