Revert "[Sanitizers] UBSan unreachable incompatible with ASan in the presence of noreturn calls"

This reverts commit r352690. This causes clang to crash. Sent reproducer to the
author in the orginal commit.

llvm-svn: 352755

Author: Eric Liu

clang/lib/CodeGen/CGCall.cpp

@@ -4398,23 +4398,10 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
 
     // Strip away the noreturn attribute to better diagnose unreachable UB.
     if (SanOpts.has(SanitizerKind::Unreachable)) {
-      // Also remove from function since CI->hasFnAttr(..) also checks attributes
-      // of the called function.
       if (auto *F = CI->getCalledFunction())
         F->removeFnAttr(llvm::Attribute::NoReturn);
       CI->removeAttribute(llvm::AttributeList::FunctionIndex,
                           llvm::Attribute::NoReturn);
-
-      // Avoid incompatibility with ASan which relies on the `noreturn`
-      // attribute to insert handler calls.
-      if (SanOpts.has(SanitizerKind::Address)) {
-        SanitizerScope SanScope(this);
-        Builder.SetInsertPoint(CI);
-        auto *FnType = llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
-        auto *Fn = CGM.CreateRuntimeFunction(FnType, "__asan_handle_no_return");
-        EmitNounwindRuntimeCall(Fn);
-        Builder.SetInsertPoint(CI->getParent());
-      }
     }
 
     EmitUnreachable(Loc);

clang/lib/CodeGen/CodeGenFunction.h

@@ -4084,8 +4084,8 @@ class CodeGenFunction : public CodeGenTypeCache {
   /// passing to a runtime sanitizer handler.
   llvm::Constant *EmitCheckSourceLocation(SourceLocation Loc);
 
-  /// Create a basic block that will either trap or call a handler function in
-  /// the UBSan runtime with the provided arguments, and create a conditional
+  /// Create a basic block that will call a handler function in a
+  /// sanitizer runtime with the provided arguments, and create a conditional
   /// branch to it.
   void EmitCheck(ArrayRef<std::pair<llvm::Value *, SanitizerMask>> Checked,
                  SanitizerHandler Check, ArrayRef<llvm::Constant *> StaticArgs,

clang/test/CodeGen/ubsan-asan-noreturn.c

@@ -1,61 +1,63 @@
 // RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -o - %s -fsanitize=unreachable | FileCheck %s
 
-void abort() __attribute__((noreturn));
+extern void __attribute__((noreturn)) abort();
 
-// CHECK-LABEL: define void @_Z14calls_noreturnv()
+// CHECK-LABEL: define void @_Z14calls_noreturnv
 void calls_noreturn() {
-  // Check absence ([^#]*) of call site attributes (including noreturn)
-  // CHECK: call void @_Z5abortv(){{[^#]*}}
   abort();
 
+  // Check that there are no attributes on the call site.
+  // CHECK-NOT: call void @_Z5abortv{{.*}}#
+
   // CHECK: __ubsan_handle_builtin_unreachable
   // CHECK: unreachable
 }
 
 struct A {
-  // CHECK: declare void @_Z5abortv() [[EXTERN_FN_ATTR:#[0-9]+]]
+  // CHECK: declare void @_Z5abortv{{.*}} [[ABORT_ATTR:#[0-9]+]]
 
   // CHECK-LABEL: define linkonce_odr void @_ZN1A5call1Ev
   void call1() {
-    // CHECK: call void @_ZN1A16does_not_return2Ev({{.*}}){{[^#]*}}
+    // CHECK-NOT: call void @_ZN1A16does_not_return2Ev{{.*}}#
     does_not_return2();
 
     // CHECK: __ubsan_handle_builtin_unreachable
     // CHECK: unreachable
   }
 
-  // Test static members. Checks are below after `struct A` scope ends.
-  static void does_not_return1() __attribute__((noreturn)) {
+  // Test static members.
+  static void __attribute__((noreturn)) does_not_return1() {
+    // CHECK-NOT: call void @_Z5abortv{{.*}}#
     abort();
   }
 
   // CHECK-LABEL: define linkonce_odr void @_ZN1A5call2Ev
   void call2() {
-    // CHECK: call void @_ZN1A16does_not_return1Ev(){{[^#]*}}
+    // CHECK-NOT: call void @_ZN1A16does_not_return1Ev{{.*}}#
     does_not_return1();
 
     // CHECK: __ubsan_handle_builtin_unreachable
     // CHECK: unreachable
   }
 
   // Test calls through pointers to non-static member functions.
-  typedef void (A::*MemFn)() __attribute__((noreturn));
+  typedef void __attribute__((noreturn)) (A::*MemFn)();
 
   // CHECK-LABEL: define linkonce_odr void @_ZN1A5call3Ev
   void call3() {
     MemFn MF = &A::does_not_return2;
-    // CHECK: call void %{{[0-9]+\(.*}}){{[^#]*}}
     (this->*MF)();
 
+    // CHECK-NOT: call void %{{.*}}#
     // CHECK: __ubsan_handle_builtin_unreachable
     // CHECK: unreachable
   }
 
   // Test regular members.
   // CHECK-LABEL: define linkonce_odr void @_ZN1A16does_not_return2Ev({{.*}})
-  // CHECK-SAME: [[USER_FN_ATTR:#[0-9]+]]
-  void does_not_return2() __attribute__((noreturn)) {
-    // CHECK: call void @_Z5abortv(){{[^#]*}}
+  // CHECK-SAME: [[DOES_NOT_RETURN_ATTR:#[0-9]+]]
+  void __attribute__((noreturn)) does_not_return2() {
+    // CHECK-NOT: call void @_Z5abortv(){{.*}}#
     abort();
 
     // CHECK: call void @__ubsan_handle_builtin_unreachable
@@ -66,9 +68,7 @@ struct A {
   }
 };
 
-// CHECK-LABEL: define linkonce_odr void @_ZN1A16does_not_return1Ev()
-// CHECK-SAME: [[USER_FN_ATTR]]
-// CHECK: call void @_Z5abortv(){{[^#]*}}
+// CHECK: define linkonce_odr void @_ZN1A16does_not_return1Ev() [[DOES_NOT_RETURN_ATTR]]
 
 void force_irgen() {
   A a;
@@ -77,7 +77,5 @@ void force_irgen() {
   a.call3();
 }
 
-// `noreturn` should be removed from functions and call sites
-// CHECK-LABEL: attributes
-// CHECK-NOT: [[USER_FN_ATTR]] = { {{.*noreturn.*}} }
-// CHECK-NOT: [[EXTERN_FN_ATTR]] = { {{.*noreturn.*}} }
+// CHECK-NOT: [[ABORT_ATTR]] = {{[^}]+}}noreturn
+// CHECK-NOT: [[DOES_NOT_RETURN_ATTR]] = {{[^}]+}}noreturn