[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).

llvm-svn: 231150

1 files changed, 6 insertions, 9 deletions

diff --git a/clang/test/CodeGen/catch-undef-behavior.c b/clang/test/CodeGen/catch-undef-behavior.c
index c41b37c39bc..016c331fb0b 100644
--- a/clang/test/CodeGen/catch-undef-behavior.c
+++ b/clang/test/CodeGen/catch-undef-behavior.c
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -fsanitize=alignment,null,object-size,shift,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-UBSAN
-// RUN: %clang_cc1 -fsanitize-undefined-trap-on-error -fsanitize=alignment,null,object-size,shift,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-TRAP
+// RUN: %clang_cc1 -fsanitize=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-UBSAN
+// RUN: %clang_cc1 -fsanitize-undefined-trap-on-error -fsanitize=alignment,null,object-size,shift-base,shift-exponent,return,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -fsanitize-recover=alignment,null,object-size,shift-base,shift-exponent,signed-integer-overflow,vla-bound,float-cast-overflow,integer-divide-by-zero,bool,returns-nonnull-attribute,nonnull-attribute -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-COMMON --check-prefix=CHECK-TRAP
 // RUN: %clang_cc1 -fsanitize=null -fsanitize-recover=null -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-NULL
 // RUN: %clang_cc1 -fsanitize=signed-integer-overflow -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s --check-prefix=CHECK-OVERFLOW
 
@@ -83,15 +83,12 @@ int addr_space(int __attribute__((address_space(256))) *a) {
 
 // CHECK-COMMON-LABEL: @lsh_overflow
 int lsh_overflow(int a, int b) {
-  // CHECK-COMMON:      %[[INBOUNDS:.*]] = icmp ule i32 %[[RHS:.*]], 31
-  // CHECK-COMMON-NEXT: br i1 %[[INBOUNDS]], label %[[CHECKBB:.*]], label %[[CONTBB:.*]]
-
-  // CHECK-COMMON:      %[[SHIFTED_OUT_WIDTH:.*]] = sub nuw nsw i32 31, %[[RHS]]
+  // CHECK-COMMON:      %[[RHS_INBOUNDS:.*]] = icmp ule i32 %[[RHS:.*]], 31
+  // CHECK-COMMON-NEXT: %[[SHIFTED_OUT_WIDTH:.*]] = sub nuw nsw i32 31, %[[RHS]]
   // CHECK-COMMON-NEXT: %[[SHIFTED_OUT:.*]] = lshr i32 %[[LHS:.*]], %[[SHIFTED_OUT_WIDTH]]
   // CHECK-COMMON-NEXT: %[[NO_OVERFLOW:.*]] = icmp eq i32 %[[SHIFTED_OUT]], 0
-  // CHECK-COMMON-NEXT: br label %[[CONTBB]]
+  // CHECK-COMMON-NEXT: %[[VALID:.*]] = and i1 %[[RHS_INBOUNDS]], %[[NO_OVERFLOW]]
 
-  // CHECK-COMMON:      %[[VALID:.*]] = phi i1 [ %[[INBOUNDS]], {{.*}} ], [ %[[NO_OVERFLOW]], %[[CHECKBB]] ]
   // CHECK-UBSAN: br i1 %[[VALID]], {{.*}} !prof ![[WEIGHT_MD]]
   // CHECK-TRAP:  br i1 %[[VALID]]
 
@@ -122,7 +119,7 @@ int rsh_inbounds(int a, int b) {
   // CHECK-TRAP:      call void @llvm.trap() [[NR_NUW]]
   // CHECK-TRAP-NEXT: unreachable
 
-  // CHECK-COMMON:      %[[RET:.*]] = ashr i32 %[[LHS]], %[[RHS]]
+  // CHECK-COMMON:      %[[RET:.*]] = ashr i32 {{.*}}, %[[RHS]]
   // CHECK-COMMON-NEXT: ret i32 %[[RET]]
 #line 400
   return a >> b;