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

This is a recommit of r231150, reverted in r231409. Turns out
that -fsanitize=shift-base check implementation only works if the
shift exponent is valid, otherwise it contains undefined behavior
itself.

Make sure we check that exponent is valid before we proceed to
check the base. Make sure that we actually report invalid values
of base or exponent if -fsanitize=shift-base or
-fsanitize=shift-exponent is specified, respectively.

llvm-svn: 231711

1 files changed, 9 insertions, 5 deletions

diff --git a/clang/test/CodeGenCXX/catch-undef-behavior.cpp b/clang/test/CodeGenCXX/catch-undef-behavior.cpp
index d0491a9dc98..168fbc25f61 100644
--- a/clang/test/CodeGenCXX/catch-undef-behavior.cpp
+++ b/clang/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 +130,11 @@ 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: %[[RHS_INBOUNDS:.*]] = icmp ule i32 %[[RHS:.*]], 31
+  // CHECK-NEXT: br i1 %[[RHS_INBOUNDS]], label %[[CHECK_BB:.*]], label %[[CONT_BB:.*]],
 
-  // CHECK: %[[SHIFTED_OUT_WIDTH:.*]] = sub nuw nsw i32 31, %[[RHS]]
+  // CHECK:      [[CHECK_BB]]:
+  // 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'
@@ -141,8 +142,11 @@ int lsh_overflow(int a, int b) {
   // CHECK-NEXT: %[[SHIFTED_OUT_NOT_SIGN:.*]] = lshr i32 %[[SHIFTED_OUT]], 1
 
   // CHECK-NEXT: %[[NO_OVERFLOW:.*]] = icmp eq i32 %[[SHIFTED_OUT_NOT_SIGN]], 0
+  // CHECK-NEXT: br label %[[CONT_BB]]
 
-  // CHECK: %[[VALID:.*]] = phi i1 [ %[[INBOUNDS]], {{.*}} ], [ %[[NO_OVERFLOW]], {{.*}} ]
+  // CHECK:      [[CONT_BB]]:
+  // CHECK-NEXT: %[[VALID_BASE:.*]] = phi i1 [ true, {{.*}} ], [ %[[NO_OVERFLOW]], %[[CHECK_BB]] ]
+  // CHECK-NEXT: %[[VALID:.*]] = and i1 %[[RHS_INBOUNDS]], %[[VALID_BASE]]
   // CHECK-NEXT: br i1 %[[VALID]]
 
   // CHECK: call void @__ubsan_handle_shift_out_of_bounds