Author: vedantk
Date: Mon Feb 27 13:46:19 2017
New Revision: 296374
URL: http://llvm.org/viewvc/llvm-project?rev=296374&view=rev
Log:
[ubsan] Factor out logic to emit a range check. NFC.
This is a readability improvement, but it will also help prep an
upcoming patch to detect UB loads from bitfields.
Modified:
cfe/trunk/lib/CodeGen/CGExpr.cpp
cfe/trunk/lib/CodeGen/CodeGenFunction.h
Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=296374&r1=296373&r2=296374&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Mon Feb 27 13:46:19 2017
@@ -1301,6 +1301,46 @@ llvm::MDNode *CodeGenFunction::getRangeF
return MDHelper.createRange(Min, End);
}
+bool CodeGenFunction::EmitScalarRangeCheck(llvm::Value *Value, QualType Ty,
+ SourceLocation Loc) {
+ bool HasBoolCheck = SanOpts.has(SanitizerKind::Bool);
+ bool HasEnumCheck = SanOpts.has(SanitizerKind::Enum);
+ if (!HasBoolCheck && !HasEnumCheck)
+ return false;
+
+ bool IsBool = hasBooleanRepresentation(Ty) ||
+ NSAPI(CGM.getContext()).isObjCBOOLType(Ty);
+ bool NeedsBoolCheck = HasBoolCheck && IsBool;
+ bool NeedsEnumCheck = HasEnumCheck && Ty->getAs<EnumType>();
+ if (!NeedsBoolCheck && !NeedsEnumCheck)
+ return false;
+
+ llvm::APInt Min, End;
+ if (!getRangeForType(*this, Ty, Min, End, /*StrictEnums=*/true, IsBool))
+ return true;
+
+ SanitizerScope SanScope(this);
+ llvm::Value *Check;
+ --End;
+ if (!Min) {
+ Check = Builder.CreateICmpULE(
+ Value, llvm::ConstantInt::get(getLLVMContext(), End));
+ } else {
+ llvm::Value *Upper = Builder.CreateICmpSLE(
+ Value, llvm::ConstantInt::get(getLLVMContext(), End));
+ llvm::Value *Lower = Builder.CreateICmpSGE(
+ Value, llvm::ConstantInt::get(getLLVMContext(), Min));
+ Check = Builder.CreateAnd(Upper, Lower);
+ }
+ llvm::Constant *StaticArgs[] = {EmitCheckSourceLocation(Loc),
+ EmitCheckTypeDescriptor(Ty)};
+ SanitizerMask Kind =
+ NeedsEnumCheck ? SanitizerKind::Enum : SanitizerKind::Bool;
+ EmitCheck(std::make_pair(Check, Kind), SanitizerHandler::LoadInvalidValue,
+ StaticArgs, EmitCheckValue(Value));
+ return true;
+}
+
llvm::Value *CodeGenFunction::EmitLoadOfScalar(Address Addr, bool Volatile,
QualType Ty,
SourceLocation Loc,
@@ -1353,35 +1393,9 @@ llvm::Value *CodeGenFunction::EmitLoadOf
false /*ConvertTypeToTag*/);
}
- bool IsBool = hasBooleanRepresentation(Ty) ||
- NSAPI(CGM.getContext()).isObjCBOOLType(Ty);
- bool NeedsBoolCheck = SanOpts.has(SanitizerKind::Bool) && IsBool;
- bool NeedsEnumCheck =
- SanOpts.has(SanitizerKind::Enum) && Ty->getAs<EnumType>();
- if (NeedsBoolCheck || NeedsEnumCheck) {
- SanitizerScope SanScope(this);
- llvm::APInt Min, End;
- if (getRangeForType(*this, Ty, Min, End, /*StrictEnums=*/true, IsBool)) {
- --End;
- llvm::Value *Check;
- if (!Min)
- Check = Builder.CreateICmpULE(
- Load, llvm::ConstantInt::get(getLLVMContext(), End));
- else {
- llvm::Value *Upper = Builder.CreateICmpSLE(
- Load, llvm::ConstantInt::get(getLLVMContext(), End));
- llvm::Value *Lower = Builder.CreateICmpSGE(
- Load, llvm::ConstantInt::get(getLLVMContext(), Min));
- Check = Builder.CreateAnd(Upper, Lower);
- }
- llvm::Constant *StaticArgs[] = {
- EmitCheckSourceLocation(Loc),
- EmitCheckTypeDescriptor(Ty)
- };
- SanitizerMask Kind = NeedsEnumCheck ? SanitizerKind::Enum :
SanitizerKind::Bool;
- EmitCheck(std::make_pair(Check, Kind),
SanitizerHandler::LoadInvalidValue,
- StaticArgs, EmitCheckValue(Load));
- }
+ if (EmitScalarRangeCheck(Load, Ty, Loc)) {
+ // In order to prevent the optimizer from throwing away the check, don't
+ // attach range metadata to the load.
} else if (CGM.getCodeGenOpts().OptimizationLevel > 0)
if (llvm::MDNode *RangeInfo = getRangeForLoadFromType(Ty))
Load->setMetadata(llvm::LLVMContext::MD_range, RangeInfo);
Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=296374&r1=296373&r2=296374&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Mon Feb 27 13:46:19 2017
@@ -2866,6 +2866,13 @@ public:
/// representation to its value representation.
llvm::Value *EmitFromMemory(llvm::Value *Value, QualType Ty);
+ /// Check if the scalar \p Value is within the valid range for the given
+ /// type \p Ty.
+ ///
+ /// Returns true if a check is needed (even if the range is unknown).
+ bool EmitScalarRangeCheck(llvm::Value *Value, QualType Ty,
+ SourceLocation Loc);
+
/// EmitLoadOfScalar - Load a scalar value from an address, taking
/// care to appropriately convert from the memory representation to
/// the LLVM value representation.
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