[clang][ubsan] Split Implicit Integer Truncation Sanitizer into unsigned and signed checks

Summary:
As per IRC disscussion, it seems we really want to have more fine-grained `-fsanitize=implicit-integer-truncation`:
* A check when both of the types are unsigned.
* Another check for the other cases (either one of the types is signed, or both of the types is signed).

This is clang part.
Compiler-rt part is D50902.

Reviewers: rsmith, vsk, Sanitizers

Reviewed by: rsmith

Differential Revision: https://reviews.llvm.org/D50901

llvm-svn: 344230

1 files changed, 109 insertions, 0 deletions

diff --git a/clang/test/CodeGen/catch-implicit-unsigned-integer-truncations-basics.c b/clang/test/CodeGen/catch-implicit-unsigned-integer-truncations-basics.c
new file mode 100644
index 00000000000..7eb0f0f8c91
--- /dev/null
+++ b/clang/test/CodeGen/catch-implicit-unsigned-integer-truncations-basics.c
@@ -0,0 +1,109 @@
+// RUN: %clang_cc1 -fsanitize=implicit-unsigned-integer-truncation -fsanitize-recover=implicit-unsigned-integer-truncation -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s -implicit-check-not="call void @__ubsan_handle_implicit_conversion" --check-prefixes=CHECK
+
+// Test plan:
+//  * Two types - int and char
+//  * Two signs - signed and unsigned
+//  * Square that - we have input and output types.
+// Thus, there are total of (2*2)^2 == 16 tests.
+// These are all the possible variations/combinations of casts.
+// However, not all of them should result in the check.
+// So here, we *only* check which should and which should not result in checks.
+
+// CHECK-DAG: @[[LINE_500_UNSIGNED_TRUNCATION:.*]] = {{.*}}, i32 500, i32 10 }, {{.*}}, {{.*}}, i8 1 }
+
+// CHECK-LABEL: @convert_unsigned_int_to_unsigned_int
+unsigned int convert_unsigned_int_to_unsigned_int(unsigned int x) {
+#line 100
+  return x;
+}
+
+// CHECK-LABEL: @convert_unsigned_char_to_unsigned_char
+unsigned char convert_unsigned_char_to_unsigned_char(unsigned char x) {
+#line 200
+  return x;
+}
+
+// CHECK-LABEL: @convert_signed_int_to_signed_int
+signed int convert_signed_int_to_signed_int(signed int x) {
+#line 300
+  return x;
+}
+
+// CHECK-LABEL: @convert_signed_char_to_signed_char
+signed char convert_signed_char_to_signed_char(signed char x) {
+#line 400
+  return x;
+}
+
+// CHECK-LABEL: @convert_unsigned_int_to_unsigned_char
+unsigned char convert_unsigned_int_to_unsigned_char(unsigned int x) {
+  // CHECK: call void @__ubsan_handle_implicit_conversion(i8* bitcast ({ {{{.*}}}, {{{.*}}}*, {{{.*}}}*, i8 }* @[[LINE_500_UNSIGNED_TRUNCATION]] to i8*)
+#line 500
+  return x;
+}
+
+// CHECK-LABEL: @convert_unsigned_char_to_unsigned_int
+unsigned int convert_unsigned_char_to_unsigned_int(unsigned char x) {
+#line 600
+  return x;
+}
+
+// CHECK-LABEL: @convert_unsigned_char_to_signed_int
+signed int convert_unsigned_char_to_signed_int(unsigned char x) {
+#line 700
+  return x;
+}
+
+// CHECK-LABEL: @convert_signed_char_to_signed_int
+signed int convert_signed_char_to_signed_int(signed char x) {
+#line 800
+  return x;
+}
+
+// CHECK-LABEL: @convert_unsigned_int_to_signed_int
+signed int convert_unsigned_int_to_signed_int(unsigned int x) {
+#line 900
+  return x;
+}
+
+// CHECK-LABEL: @convert_signed_int_to_unsigned_int
+unsigned int convert_signed_int_to_unsigned_int(signed int x) {
+#line 1000
+  return x;
+}
+
+// CHECK-LABEL: @convert_signed_int_to_unsigned_char
+unsigned char convert_signed_int_to_unsigned_char(signed int x) {
+#line 1100
+  return x;
+}
+
+// CHECK-LABEL: @convert_signed_char_to_unsigned_char
+unsigned char convert_signed_char_to_unsigned_char(signed char x) {
+#line 1200
+  return x;
+}
+
+// CHECK-LABEL: @convert_unsigned_char_to_signed_char
+signed char convert_unsigned_char_to_signed_char(unsigned char x) {
+#line 1300
+  return x;
+}
+
+// CHECK-LABEL: @convert_signed_char_to_unsigned_int
+unsigned int convert_signed_char_to_unsigned_int(signed char x) {
+#line 1400
+  return x;
+}
+
+// CHECK-LABEL: @convert_unsigned_int_to_signed_char
+signed char convert_unsigned_int_to_signed_char(unsigned int x) {
+#line 1500
+  return x;
+}
+
+// CHECK-LABEL: @convert_signed_int_to_signed_char
+signed char convert_signed_int_to_signed_char(signed int x) {
+#line 1600
+  return x;
+}