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Sanitizer: Support -fwrapv with -fsanitize=signed-integer-overflow #82432

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Feb 21, 2024
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Sanitizer: Support -fwrapv with -fsanitize=signed-integer-overflow #82432

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b02b09b
support fwrapv with signed int overflow sanitizer
JustinStitt Feb 20, 2024
e5e92e6
run git clang-format
JustinStitt Feb 20, 2024
0182698
add release note regarding noise
JustinStitt Feb 20, 2024
1d9cb0a
update tests to use common prefix
JustinStitt Feb 20, 2024
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3 changes: 3 additions & 0 deletions clang/docs/ReleaseNotes.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -399,6 +399,9 @@ Moved checkers
Sanitizers
----------

- ``-fsanitize=signed-integer-overflow`` now instruments signed arithmetic even
when ``-fwrapv`` is enabled. Previously, only division checks were enabled.
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Python Binding Changes
----------------------

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9 changes: 5 additions & 4 deletions clang/docs/UndefinedBehaviorSanitizer.rst
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Expand Up @@ -190,10 +190,11 @@ Available checks are:
- ``-fsanitize=signed-integer-overflow``: Signed integer overflow, where the
result of a signed integer computation cannot be represented in its type.
This includes all the checks covered by ``-ftrapv``, as well as checks for
signed division overflow (``INT_MIN/-1``), but not checks for
lossy implicit conversions performed before the computation
(see ``-fsanitize=implicit-conversion``). Both of these two issues are
handled by ``-fsanitize=implicit-conversion`` group of checks.
signed division overflow (``INT_MIN/-1``). Note that checks are still
added even when ``-fwrapv`` is enabled. This sanitizer does not check for
lossy implicit conversions performed before the computation (see
``-fsanitize=implicit-conversion``). Both of these two issues are handled
by ``-fsanitize=implicit-conversion`` group of checks.
- ``-fsanitize=unreachable``: If control flow reaches an unreachable
program point.
- ``-fsanitize=unsigned-integer-overflow``: Unsigned integer overflow, where
Expand Down
16 changes: 12 additions & 4 deletions clang/lib/CodeGen/CGExprScalar.cpp
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Expand Up @@ -723,7 +723,9 @@ class ScalarExprEmitter
if (Ops.Ty->isSignedIntegerOrEnumerationType()) {
switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
case LangOptions::SOB_Defined:
return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
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return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul");
[[fallthrough]];
case LangOptions::SOB_Undefined:
if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
return Builder.CreateNSWMul(Ops.LHS, Ops.RHS, "mul");
Expand Down Expand Up @@ -2568,7 +2570,9 @@ llvm::Value *ScalarExprEmitter::EmitIncDecConsiderOverflowBehavior(
StringRef Name = IsInc ? "inc" : "dec";
switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
case LangOptions::SOB_Defined:
return Builder.CreateAdd(InVal, Amount, Name);
if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
return Builder.CreateAdd(InVal, Amount, Name);
[[fallthrough]];
case LangOptions::SOB_Undefined:
if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
return Builder.CreateNSWAdd(InVal, Amount, Name);
Expand Down Expand Up @@ -3913,7 +3917,9 @@ Value *ScalarExprEmitter::EmitAdd(const BinOpInfo &op) {
if (op.Ty->isSignedIntegerOrEnumerationType()) {
switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
case LangOptions::SOB_Defined:
return Builder.CreateAdd(op.LHS, op.RHS, "add");
if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
return Builder.CreateAdd(op.LHS, op.RHS, "add");
[[fallthrough]];
case LangOptions::SOB_Undefined:
if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
return Builder.CreateNSWAdd(op.LHS, op.RHS, "add");
Expand Down Expand Up @@ -4067,7 +4073,9 @@ Value *ScalarExprEmitter::EmitSub(const BinOpInfo &op) {
if (op.Ty->isSignedIntegerOrEnumerationType()) {
switch (CGF.getLangOpts().getSignedOverflowBehavior()) {
case LangOptions::SOB_Defined:
return Builder.CreateSub(op.LHS, op.RHS, "sub");
if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
return Builder.CreateSub(op.LHS, op.RHS, "sub");
[[fallthrough]];
case LangOptions::SOB_Undefined:
if (!CGF.SanOpts.has(SanitizerKind::SignedIntegerOverflow))
return Builder.CreateNSWSub(op.LHS, op.RHS, "sub");
Expand Down
12 changes: 12 additions & 0 deletions clang/test/CodeGen/integer-overflow.c
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Expand Up @@ -2,6 +2,7 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -emit-llvm -o - -fwrapv | FileCheck %s --check-prefix=WRAPV
// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -emit-llvm -o - -ftrapv | FileCheck %s --check-prefix=TRAPV
// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -emit-llvm -o - -fsanitize=signed-integer-overflow | FileCheck %s --check-prefix=CATCH_UB
// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -emit-llvm -o - -fsanitize=signed-integer-overflow -fwrapv | FileCheck %s --check-prefix=CATCH_WRAP
// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -emit-llvm -o - -ftrapv -ftrapv-handler foo | FileCheck %s --check-prefix=TRAPV_HANDLER


Expand All @@ -16,27 +17,31 @@ void test1(void) {
// WRAPV: add i32
// TRAPV: llvm.sadd.with.overflow.i32
// CATCH_UB: llvm.sadd.with.overflow.i32
// CATCH_WRAP: llvm.sadd.with.overflow.i32
// TRAPV_HANDLER: foo(
f11G = a + b;

// DEFAULT: sub nsw i32
// WRAPV: sub i32
// TRAPV: llvm.ssub.with.overflow.i32
// CATCH_UB: llvm.ssub.with.overflow.i32
// CATCH_WRAP: llvm.ssub.with.overflow.i32
// TRAPV_HANDLER: foo(
f11G = a - b;

// DEFAULT: mul nsw i32
// WRAPV: mul i32
// TRAPV: llvm.smul.with.overflow.i32
// CATCH_UB: llvm.smul.with.overflow.i32
// CATCH_WRAP: llvm.smul.with.overflow.i32
// TRAPV_HANDLER: foo(
f11G = a * b;

// DEFAULT: sub nsw i32 0,
// WRAPV: sub i32 0,
// TRAPV: llvm.ssub.with.overflow.i32(i32 0
// CATCH_UB: llvm.ssub.with.overflow.i32(i32 0
// CATCH_WRAP: llvm.ssub.with.overflow.i32(i32 0
// TRAPV_HANDLER: foo(
f11G = -a;

Expand All @@ -46,13 +51,15 @@ void test1(void) {
// WRAPV: add i32 {{.*}}, 1
// TRAPV: llvm.sadd.with.overflow.i32({{.*}}, i32 1)
// CATCH_UB: llvm.sadd.with.overflow.i32({{.*}}, i32 1)
// CATCH_WRAP: llvm.sadd.with.overflow.i32({{.*}}, i32 1)
// TRAPV_HANDLER: foo(
++a;

// DEFAULT: add nsw i32 {{.*}}, -1
// WRAPV: add i32 {{.*}}, -1
// TRAPV: llvm.ssub.with.overflow.i32({{.*}}, i32 1)
// CATCH_UB: llvm.ssub.with.overflow.i32({{.*}}, i32 1)
// CATCH_WRAP: llvm.ssub.with.overflow.i32({{.*}}, i32 1)
// TRAPV_HANDLER: foo(
--a;

Expand All @@ -70,6 +77,7 @@ void test1(void) {
// WRAPV: add i8 {{.*}}, 1
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// TRAPV: add i8 {{.*}}, 1
// CATCH_UB: add i8 {{.*}}, 1
// CATCH_WRAP: add i8 {{.*}}, 1
++PR9350_char_inc;

// PR9350: char pre-decrement never overflows.
Expand All @@ -78,6 +86,7 @@ void test1(void) {
// WRAPV: add i8 {{.*}}, -1
// TRAPV: add i8 {{.*}}, -1
// CATCH_UB: add i8 {{.*}}, -1
// CATCH_WRAP: add i8 {{.*}}, -1
--PR9350_char_dec;

// PR9350: short pre-increment never overflows.
Expand All @@ -86,6 +95,7 @@ void test1(void) {
// WRAPV: add i16 {{.*}}, 1
// TRAPV: add i16 {{.*}}, 1
// CATCH_UB: add i16 {{.*}}, 1
// CATCH_WRAP: add i16 {{.*}}, 1
++PR9350_short_inc;

// PR9350: short pre-decrement never overflows.
Expand All @@ -94,6 +104,7 @@ void test1(void) {
// WRAPV: add i16 {{.*}}, -1
// TRAPV: add i16 {{.*}}, -1
// CATCH_UB: add i16 {{.*}}, -1
// CATCH_WRAP: add i16 {{.*}}, -1
--PR9350_short_dec;

// PR24256: don't instrument __builtin_frame_address.
Expand All @@ -102,4 +113,5 @@ void test1(void) {
// WRAPV: call ptr @llvm.frameaddress.p0(i32 0)
// TRAPV: call ptr @llvm.frameaddress.p0(i32 0)
// CATCH_UB: call ptr @llvm.frameaddress.p0(i32 0)
// CATCH_WRAP: call ptr @llvm.frameaddress.p0(i32 0)
}
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