[UBSan] Split -fsanitize=shift into -fsanitize=shift-base and -fsanitize=shift-exponent.

-fsanitize=shift is now a group that includes both these checks, so
exisiting users should not be affected.

This change introduces two new UBSan kinds that sanitize only left-hand
side and right-hand side of shift operation. In practice, invalid
exponent value (negative or too large) tends to cause more portability
problems, including inconsistencies between different compilers, crashes
and inadequeate results on non-x86 architectures etc. That is,
-fsanitize=shift-exponent failures should generally be addressed first.

As a bonus, this change simplifies CodeGen implementation for emitting left
shift (separate checks for base and exponent are now merged by the
existing generic logic in EmitCheck()), and LLVM IR for these checks
(the number of basic blocks is reduced).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@231150 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 6 deletions

diff --git a/test/CodeGenCXX/catch-undef-behavior.cpp b/test/CodeGenCXX/catch-undef-behavior.cpp
index d0491a9dc9..6d81ddb7d4 100644
--- a/test/CodeGenCXX/catch-undef-behavior.cpp
+++ b/test/CodeGenCXX/catch-undef-behavior.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -std=c++11 -fsanitize=signed-integer-overflow,integer-divide-by-zero,float-divide-by-zero,shift,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,vla-bound,alignment,null,vptr,object-size,float-cast-overflow,bool,enum,array-bounds,function -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s
+// 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 | FileCheck %s
 // 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
@@ -130,10 +130,8 @@ void member_access(S *p) {
 
 // CHECK-LABEL: @_Z12lsh_overflow
 int lsh_overflow(int a, int b) {
-  // CHECK: %[[INBOUNDS:.*]] = icmp ule i32 %[[RHS:.*]], 31
-  // CHECK-NEXT: br i1 %[[INBOUNDS]]
-
-  // CHECK: %[[SHIFTED_OUT_WIDTH:.*]] = sub nuw nsw i32 31, %[[RHS]]
+  // CHECK: %[[RHS_INBOUNDS:.*]] = icmp ule i32 %[[RHS:.*]], 31
+  // CHECK-NEXT: %[[SHIFTED_OUT_WIDTH:.*]] = sub nuw nsw i32 31, %[[RHS]]
   // CHECK-NEXT: %[[SHIFTED_OUT:.*]] = lshr i32 %[[LHS:.*]], %[[SHIFTED_OUT_WIDTH]]
 
   // This is present for C++11 but not for C: C++ core issue 1457 allows a '1'
@@ -142,7 +140,7 @@ int lsh_overflow(int a, int b) {
 
   // CHECK-NEXT: %[[NO_OVERFLOW:.*]] = icmp eq i32 %[[SHIFTED_OUT_NOT_SIGN]], 0
 
-  // CHECK: %[[VALID:.*]] = phi i1 [ %[[INBOUNDS]], {{.*}} ], [ %[[NO_OVERFLOW]], {{.*}} ]
+  // CHECK-NEXT: %[[VALID:.*]] = and i1 %[[RHS_INBOUNDS]], %[[NO_OVERFLOW]]
   // CHECK-NEXT: br i1 %[[VALID]]
 
   // CHECK: call void @__ubsan_handle_shift_out_of_bounds