artem updated this revision to Diff 550013.
artem marked 5 inline comments as done.
artem edited the summary of this revision.
artem added a comment.
Fixed review comments
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D156821/new/
https://reviews.llvm.org/D156821
Files:
clang/docs/ReleaseNotes.rst
clang/lib/CodeGen/CGBuiltin.cpp
clang/test/CodeGen/abs-overflow.c
compiler-rt/test/ubsan/TestCases/Misc/abs.cpp
Index: compiler-rt/test/ubsan/TestCases/Misc/abs.cpp
===================================================================
--- /dev/null
+++ compiler-rt/test/ubsan/TestCases/Misc/abs.cpp
@@ -0,0 +1,30 @@
+// REQUIRES: arch=x86_64
+//
+// RUN: %clangxx -fsanitize=signed-integer-overflow -w %s -O3 -o %t
+// RUN: %run %t 2>&1 | FileCheck %s --check-prefix=RECOVER
+//
+// RUN: %clangxx -fsanitize=signed-integer-overflow -fno-sanitize-recover=signed-integer-overflow -w %s -O3 -o %t.abort
+// RUN: not %run %t.abort 2>&1 | FileCheck %s --check-prefix=ABORT
+
+#include <limits.h>
+#include <stdlib.h>
+
+int main() {
+ // ABORT: abs.cpp:[[@LINE+3]]:17: runtime error: negation of -{{[0-9]+}} cannot be represented in type 'int'; cast to an unsigned type to negate this value to itself
+ // RECOVER: abs.cpp:[[@LINE+2]]:17: runtime error: negation of -{{[0-9]+}} cannot be represented in type 'int'; cast to an unsigned type to negate this value to itself
+ // RECOVER: abs.cpp:[[@LINE+2]]:7: runtime error: negation of -{{[0-9]+}} cannot be represented in type 'int'; cast to an unsigned type to negate this value to itself
+ __builtin_abs(INT_MIN);
+ abs(INT_MIN);
+
+ // RECOVER: abs.cpp:[[@LINE+2]]:18: runtime error: negation of -{{[0-9]+}} cannot be represented in type 'long'; cast to an unsigned type to negate this value to itself
+ // RECOVER: abs.cpp:[[@LINE+2]]:8: runtime error: negation of -{{[0-9]+}} cannot be represented in type 'long'; cast to an unsigned type to negate this value to itself
+ __builtin_labs(LONG_MIN);
+ labs(LONG_MIN);
+
+ // RECOVER: abs.cpp:[[@LINE+2]]:19: runtime error: negation of -{{[0-9]+}} cannot be represented in type 'long long'; cast to an unsigned type to negate this value to itself
+ // RECOVER: abs.cpp:[[@LINE+2]]:9: runtime error: negation of -{{[0-9]+}} cannot be represented in type 'long long'; cast to an unsigned type to negate this value to itself
+ __builtin_llabs(LLONG_MIN);
+ llabs(LLONG_MIN);
+
+ return 0;
+}
Index: clang/test/CodeGen/abs-overflow.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/abs-overflow.c
@@ -0,0 +1,46 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm %s -o - -fwrapv -fsanitize=signed-integer-overflow | FileCheck %s --check-prefix=WRAPV
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm %s -o - -ftrapv | FileCheck %s --check-prefixes=BOTH-TRAP,TRAPV
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm %s -o - -fsanitize=signed-integer-overflow | FileCheck %s --check-prefixes=BOTH-TRAP,CATCH_UB
+// COM: TODO: Support -ftrapv-handler.
+
+extern int abs(int x);
+
+int absi(int x) {
+// WRAPV: [[NEG:%.*]] = sub i32 0, [[X:%.*]]
+// WRAPV: [[CMP:%.*]] = icmp slt i32 [[X]], 0
+// WRAPV: [[SEL:%.*]] = select i1 [[CMP]], i32 [[NEG]], i32 [[X]]
+//
+// BOTH-TRAP: [[NEG:%.*]] = call { i32, i1 } @llvm.ssub.with.overflow.i32(i32 0, i32 [[X:%.*]])
+// BOTH-TRAP: [[NEGV:%.*]] = extractvalue { i32, i1 } [[NEG]], 0
+// BOTH-TRAP: [[OFL:%.*]] = extractvalue { i32, i1 } [[NEG]], 1
+// BOTH-TRAP: [[NOFL:%.*]] = xor i1 [[OFL]], true
+// BOTH-TRAP: br i1 [[NOFL]], label %[[CONT:.*]], label %[[TRAP:[a-zA-Z_.]*]]
+// BOTH-TRAP: [[TRAP]]:
+// TRAPV-NEXT: llvm.ubsantrap
+// CATCH_UB: @__ubsan_handle_negate_overflow
+// BOTH-TRAP-NEXT: unreachable
+// BOTH-TRAP: [[CONT]]:
+// BOTH-TRAP-NEXT: [[ABSCOND:%.*]] = icmp slt i32 [[X]], 0
+// BOTH-TRAP-NEXT: select i1 [[ABSCOND]], i32 [[NEGV]], i32 [[X]]
+ return abs(x);
+}
+
+int babsi(int x) {
+// WRAPV: [[NEG:%.*]] = sub i32 0, [[X:%.*]]
+// WRAPV: [[CMP:%.*]] = icmp slt i32 [[X]], 0
+// WRAPV: [[SEL:%.*]] = select i1 [[CMP]], i32 [[NEG]], i32 [[X]]
+//
+// BOTH-TRAP: [[NEG:%.*]] = call { i32, i1 } @llvm.ssub.with.overflow.i32(i32 0, i32 [[X:%.*]])
+// BOTH-TRAP: [[NEGV:%.*]] = extractvalue { i32, i1 } [[NEG]], 0
+// BOTH-TRAP: [[OFL:%.*]] = extractvalue { i32, i1 } [[NEG]], 1
+// BOTH-TRAP: [[NOFL:%.*]] = xor i1 [[OFL]], true
+// BOTH-TRAP: br i1 [[NOFL]], label %[[CONT:.*]], label %[[TRAP:[a-zA-Z_.]*]]
+// BOTH-TRAP: [[TRAP]]:
+// TRAPV-NEXT: llvm.ubsantrap
+// CATCH_UB: @__ubsan_handle_negate_overflow
+// BOTH-TRAP-NEXT: unreachable
+// BOTH-TRAP: [[CONT]]:
+// BOTH-TRAP-NEXT: [[ABSCOND:%.*]] = icmp slt i32 [[X]], 0
+// BOTH-TRAP-NEXT: select i1 [[ABSCOND]], i32 [[NEGV]], i32 [[X]]
+ return __builtin_abs(x);
+}
Index: clang/lib/CodeGen/CGBuiltin.cpp
===================================================================
--- clang/lib/CodeGen/CGBuiltin.cpp
+++ clang/lib/CodeGen/CGBuiltin.cpp
@@ -1768,6 +1768,49 @@
return ArgValue;
}
+static Value *EmitAbs(CodeGenFunction &CGF, Value *ArgValue, bool HasNSW) {
+ // X < 0 ? -X : X
+ // TODO: Use phi-node (for better SimplifyCFGPass)
+ Value *NegOp = CGF.Builder.CreateNeg(ArgValue, "neg", false, HasNSW);
+ Constant *Zero = llvm::Constant::getNullValue(ArgValue->getType());
+ Value *CmpResult = CGF.Builder.CreateICmpSLT(ArgValue, Zero, "abscond");
+ return CGF.Builder.CreateSelect(CmpResult, NegOp, ArgValue, "abs");
+}
+
+static Value *EmitOverflowCheckedAbs(CodeGenFunction &CGF, const CallExpr *E,
+ bool SanitizeOverflow) {
+ Value *ArgValue = CGF.EmitScalarExpr(E->getArg(0));
+
+ // Try to eliminate overflow check.
+ if (const auto *VCI = dyn_cast<llvm::ConstantInt>(ArgValue)) {
+ if (!VCI->isMinSignedValue()) {
+ return EmitAbs(CGF, ArgValue, true);
+ }
+ }
+
+ CodeGenFunction::SanitizerScope SanScope(&CGF);
+
+ Constant *Zero = Constant::getNullValue(ArgValue->getType());
+ Value *ResultAndOverflow = CGF.Builder.CreateBinaryIntrinsic(
+ Intrinsic::ssub_with_overflow, Zero, ArgValue);
+ Value *Result = CGF.Builder.CreateExtractValue(ResultAndOverflow, 0);
+ Value *NotOverflow = CGF.Builder.CreateNot(
+ CGF.Builder.CreateExtractValue(ResultAndOverflow, 1));
+
+ // TODO: support -ftrapv-handler.
+ if (SanitizeOverflow) {
+ CGF.EmitCheck({{NotOverflow, SanitizerKind::SignedIntegerOverflow}},
+ SanitizerHandler::NegateOverflow,
+ {CGF.EmitCheckSourceLocation(E->getArg(0)->getExprLoc()),
+ CGF.EmitCheckTypeDescriptor(E->getType())},
+ {ArgValue});
+ } else
+ CGF.EmitTrapCheck(NotOverflow, SanitizerHandler::SubOverflow);
+
+ Value *CmpResult = CGF.Builder.CreateICmpSLT(ArgValue, Zero, "abscond");
+ return CGF.Builder.CreateSelect(CmpResult, Result, ArgValue, "abs");
+}
+
/// Get the argument type for arguments to os_log_helper.
static CanQualType getOSLogArgType(ASTContext &C, int Size) {
QualType UnsignedTy = C.getIntTypeForBitwidth(Size * 8, /*Signed=*/false);
@@ -2626,16 +2669,29 @@
Builder.CreateCall(CGM.getIntrinsic(Intrinsic::vacopy), {DstPtr, SrcPtr});
return RValue::get(nullptr);
}
+ case Builtin::BIabs:
+ case Builtin::BIlabs:
+ case Builtin::BIllabs:
case Builtin::BI__builtin_abs:
case Builtin::BI__builtin_labs:
case Builtin::BI__builtin_llabs: {
- // X < 0 ? -X : X
- // The negation has 'nsw' because abs of INT_MIN is undefined.
- Value *ArgValue = EmitScalarExpr(E->getArg(0));
- Value *NegOp = Builder.CreateNSWNeg(ArgValue, "neg");
- Constant *Zero = llvm::Constant::getNullValue(ArgValue->getType());
- Value *CmpResult = Builder.CreateICmpSLT(ArgValue, Zero, "abscond");
- Value *Result = Builder.CreateSelect(CmpResult, NegOp, ArgValue, "abs");
+ bool SanitizeOverflow = SanOpts.has(SanitizerKind::SignedIntegerOverflow);
+
+ Value *Result;
+ switch (getLangOpts().getSignedOverflowBehavior()) {
+ case LangOptions::SOB_Defined:
+ Result = EmitAbs(*this, EmitScalarExpr(E->getArg(0)), false);
+ break;
+ case LangOptions::SOB_Undefined:
+ if (!SanitizeOverflow) {
+ Result = EmitAbs(*this, EmitScalarExpr(E->getArg(0)), true);
+ break;
+ }
+ [[fallthrough]];
+ case LangOptions::SOB_Trapping:
+ Result = EmitOverflowCheckedAbs(*this, E, SanitizeOverflow);
+ break;
+ }
return RValue::get(Result);
}
case Builtin::BI__builtin_complex: {
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -138,6 +138,10 @@
class, which can result in miscompiles in some cases.
- Fix crash on use of a variadic overloaded operator.
(`#42535 <https://github.com/llvm/llvm-project/issues/42535>_`)
+- Clang now respects ``-fwrapv`` and ``-ftrapv`` for ``__builtin_abs`` and
+ ``abs`` builtins.
+ (`#45129 <https://github.com/llvm/llvm-project/issues/45129>`_,
+ `#45794 <https://github.com/llvm/llvm-project/issues/45794>`_)
Bug Fixes to Compiler Builtins
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -266,6 +270,9 @@
Sanitizers
----------
+- ``-fsanitize=signed-integer-overflow`` now instruments ``__builtin_abs`` and
+ ``abs`` builtins.
+
Python Binding Changes
----------------------
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