Index: docs/LangRef.rst =================================================================== --- docs/LangRef.rst +++ docs/LangRef.rst @@ -969,6 +969,17 @@ passed in is non-null, or the callee must ensure that the returned pointer is non-null. +``dereferenceable()`` + This indicates that the parameter or return pointer is dereferenceable. This + attribute may only be applied to pointer typed parameters. A pointer that + is dereferenceable can be loaded from speculatively without a risk of + trapping. The number of bytes known to be dereferenceable must be provided + in parentheses. It is legal for the number of bytes to be less than the + size of the pointee type. The ``nonnull`` attribute does not imply + dereferenceability (consider a pointer to one element past the end of an + array), however ``dereferenceable()`` does imply ``nonnull`` in + ``addrspace(0)`` (which is the default address space). + .. _gc: Garbage Collector Names Index: include/llvm-c/Core.h =================================================================== --- include/llvm-c/Core.h +++ include/llvm-c/Core.h @@ -168,6 +168,7 @@ LLVMInAllocaAttribute = 1ULL << 36, LLVMNonNullAttribute = 1ULL << 37, LLVMJumpTableAttribute = 1ULL << 38, + LLVMDereferenceableAttribute = 1ULL << 39, */ } LLVMAttribute; Index: include/llvm/Bitcode/LLVMBitCodes.h =================================================================== --- include/llvm/Bitcode/LLVMBitCodes.h +++ include/llvm/Bitcode/LLVMBitCodes.h @@ -374,7 +374,8 @@ ATTR_KIND_OPTIMIZE_NONE = 37, ATTR_KIND_IN_ALLOCA = 38, ATTR_KIND_NON_NULL = 39, - ATTR_KIND_JUMP_TABLE = 40 + ATTR_KIND_JUMP_TABLE = 40, + ATTR_KIND_DEFERERENCEABLE = 41 }; enum ComdatSelectionKindCodes { Index: include/llvm/IR/Argument.h =================================================================== --- include/llvm/IR/Argument.h +++ include/llvm/IR/Argument.h @@ -56,9 +56,15 @@ unsigned getArgNo() const; /// \brief Return true if this argument has the nonnull attribute on it in - /// its containing function. + /// its containing function. Also returns true if at least one byte is known + /// to be dereferenceable and the pointer is in addrspace(0). bool hasNonNullAttr() const; + /// \brief If this argument has the dereferenceable attribute on it in its + /// containing function, return the number of bytes known to be + /// dereferenceable. Otherwise, zero is returned. + uint64_t getDereferenceableBytes() const; + /// \brief Return true if this argument has the byval attribute on it in its /// containing function. bool hasByValAttr() const; Index: include/llvm/IR/Attributes.h =================================================================== --- include/llvm/IR/Attributes.h +++ include/llvm/IR/Attributes.h @@ -88,6 +88,7 @@ NonLazyBind, ///< Function is called early and/or ///< often, so lazy binding isn't worthwhile NonNull, ///< Pointer is known to be not null + Dereferenceable, ///< Pointer is known to be dereferenceable NoRedZone, ///< Disable redzone NoReturn, ///< Mark the function as not returning NoUnwind, ///< Function doesn't unwind stack @@ -133,6 +134,8 @@ /// alignment set. static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align); static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align); + static Attribute getWithDereferenceableBytes(LLVMContext &Context, + uint64_t Bytes); //===--------------------------------------------------------------------===// // Attribute Accessors @@ -141,8 +144,8 @@ /// \brief Return true if the attribute is an Attribute::AttrKind type. bool isEnumAttribute() const; - /// \brief Return true if the attribute is an alignment attribute. - bool isAlignAttribute() const; + /// \brief Return true if the attribute is an integer attribute. + bool isIntAttribute() const; /// \brief Return true if the attribute is a string (target-dependent) /// attribute. @@ -178,6 +181,10 @@ /// alignment value. unsigned getStackAlignment() const; + /// \brief Returns the number of dereferenceable bytes from the + /// dereferenceable attribute (or zero if unknown). + uint64_t getDereferenceableBytes() const; + /// \brief The Attribute is converted to a string of equivalent mnemonic. This /// is, presumably, for writing out the mnemonics for the assembly writer. std::string getAsString(bool InAttrGrp = false) const; @@ -316,6 +323,9 @@ /// \brief Get the stack alignment. unsigned getStackAlignment(unsigned Index) const; + /// \brief Get the number of dereferenceable bytes (or zero if unknown). + uint64_t getDereferenceableBytes(unsigned Index) const; + /// \brief Return the attributes at the index as a string. std::string getAsString(unsigned Index, bool InAttrGrp = false) const; @@ -395,13 +405,15 @@ std::map TargetDepAttrs; uint64_t Alignment; uint64_t StackAlignment; + uint64_t DerefBytes; public: - AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0) {} + AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) {} explicit AttrBuilder(uint64_t Val) - : Attrs(0), Alignment(0), StackAlignment(0) { + : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) { addRawValue(Val); } - AttrBuilder(const Attribute &A) : Attrs(0), Alignment(0), StackAlignment(0) { + AttrBuilder(const Attribute &A) + : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) { addAttribute(A); } AttrBuilder(AttributeSet AS, unsigned Idx); @@ -455,6 +467,10 @@ /// \brief Retrieve the stack alignment attribute, if it exists. uint64_t getStackAlignment() const { return StackAlignment; } + /// \brief Retrieve the number of dereferenceable bytes, if the dereferenceable + /// attribute exists (zero is returned otherwise). + uint64_t getDereferenceableBytes() const { return DerefBytes; } + /// \brief This turns an int alignment (which must be a power of 2) into the /// form used internally in Attribute. AttrBuilder &addAlignmentAttr(unsigned Align); @@ -463,6 +479,10 @@ /// the form used internally in Attribute. AttrBuilder &addStackAlignmentAttr(unsigned Align); + /// \brief This turns the number of dereferenceable bytes into the form used + /// internally in Attribute. + AttrBuilder &addDereferenceableAttr(uint64_t Bytes); + /// \brief Return true if the builder contains no target-independent /// attributes. bool empty() const { return Attrs.none(); } Index: include/llvm/IR/CallSite.h =================================================================== --- include/llvm/IR/CallSite.h +++ include/llvm/IR/CallSite.h @@ -217,6 +217,12 @@ CALLSITE_DELEGATE_GETTER(getParamAlignment(i)); } + /// @brief Extract the number of dereferenceable bytes for a call or + /// parameter (0=unknown). + uint64_t getDereferenceableBytes(uint16_t i) const { + CALLSITE_DELEGATE_GETTER(getDereferenceableBytes(i)); + } + /// \brief Return true if the call should not be treated as a call to a /// builtin. bool isNoBuiltin() const { @@ -302,6 +308,19 @@ paramHasAttr(ArgNo + 1, Attribute::ReadNone); } + /// @brief Return true if the return value is known to be not null. + /// This may be because it has the nonnull attribute, or because at least + /// one byte is dereferenceable and the pointer is in addrspace(0). + bool isReturnNonNull() const { + if (paramHasAttr(0, Attribute::NonNull)) + return true; + else if (getDereferenceableBytes(0) > 0 && + getType()->getPointerAddressSpace() == 0) + return true; + + return false; + } + /// hasArgument - Returns true if this CallSite passes the given Value* as an /// argument to the called function. bool hasArgument(const Value *Arg) const { Index: include/llvm/IR/Function.h =================================================================== --- include/llvm/IR/Function.h +++ include/llvm/IR/Function.h @@ -233,6 +233,12 @@ return AttributeSets.getParamAlignment(i); } + /// @brief Extract the number of dereferenceable bytes for a call or + /// parameter (0=unknown). + uint64_t getDereferenceableBytes(unsigned i) const { + return AttributeSets.getDereferenceableBytes(i); + } + /// @brief Determine if the function does not access memory. bool doesNotAccessMemory() const { return AttributeSets.hasAttribute(AttributeSet::FunctionIndex, Index: include/llvm/IR/Instructions.h =================================================================== --- include/llvm/IR/Instructions.h +++ include/llvm/IR/Instructions.h @@ -1376,6 +1376,12 @@ return AttributeList.getParamAlignment(i); } + /// \brief Extract the number of dereferenceable bytes for a call or + /// parameter (0=unknown). + uint64_t getDereferenceableBytes(unsigned i) const { + return AttributeList.getDereferenceableBytes(i); + } + /// \brief Return true if the call should not be treated as a call to a /// builtin. bool isNoBuiltin() const { @@ -3051,6 +3057,12 @@ return AttributeList.getParamAlignment(i); } + /// \brief Extract the number of dereferenceable bytes for a call or + /// parameter (0=unknown). + uint64_t getDereferenceableBytes(unsigned i) const { + return AttributeList.getDereferenceableBytes(i); + } + /// \brief Return true if the call should not be treated as a call to a /// builtin. bool isNoBuiltin() const { Index: lib/Analysis/ValueTracking.cpp =================================================================== --- lib/Analysis/ValueTracking.cpp +++ lib/Analysis/ValueTracking.cpp @@ -2082,7 +2082,7 @@ return !GV->hasExternalWeakLinkage(); if (ImmutableCallSite CS = V) - if (CS.paramHasAttr(0, Attribute::NonNull)) + if (CS.isReturnNonNull()) return true; // operator new never returns null. Index: lib/AsmParser/LLLexer.cpp =================================================================== --- lib/AsmParser/LLLexer.cpp +++ lib/AsmParser/LLLexer.cpp @@ -612,6 +612,7 @@ KEYWORD(byval); KEYWORD(inalloca); KEYWORD(cold); + KEYWORD(dereferenceable); KEYWORD(inlinehint); KEYWORD(inreg); KEYWORD(jumptable); Index: lib/AsmParser/LLParser.h =================================================================== --- lib/AsmParser/LLParser.h +++ lib/AsmParser/LLParser.h @@ -202,6 +202,11 @@ Loc = Lex.getLoc(); return ParseUInt32(Val); } + bool ParseUInt64(uint64_t &Val); + bool ParseUInt64(uint64_t &Val, LocTy &Loc) { + Loc = Lex.getLoc(); + return ParseUInt64(Val); + } bool ParseTLSModel(GlobalVariable::ThreadLocalMode &TLM); bool ParseOptionalThreadLocal(GlobalVariable::ThreadLocalMode &TLM); @@ -219,6 +224,7 @@ bool ParseOptionalDLLStorageClass(unsigned &DLLStorageClass); bool ParseOptionalCallingConv(CallingConv::ID &CC); bool ParseOptionalAlignment(unsigned &Alignment); + bool ParseOptionalDereferenceableBytes(uint64_t &Bytes); bool ParseScopeAndOrdering(bool isAtomic, SynchronizationScope &Scope, AtomicOrdering &Ordering); bool ParseOrdering(AtomicOrdering &Ordering); Index: lib/AsmParser/LLParser.cpp =================================================================== --- lib/AsmParser/LLParser.cpp +++ lib/AsmParser/LLParser.cpp @@ -1052,6 +1052,7 @@ "invalid use of attribute on a function"); break; case lltok::kw_byval: + case lltok::kw_dereferenceable: case lltok::kw_inalloca: case lltok::kw_nest: case lltok::kw_noalias: @@ -1212,6 +1213,16 @@ return false; } +/// ParseUInt64 +/// ::= uint64 +bool LLParser::ParseUInt64(uint64_t &Val) { + if (Lex.getKind() != lltok::APSInt || Lex.getAPSIntVal().isSigned()) + return TokError("expected integer"); + Val = Lex.getAPSIntVal().getLimitedValue(); + Lex.Lex(); + return false; +} + /// ParseTLSModel /// := 'localdynamic' /// := 'initialexec' @@ -1284,6 +1295,13 @@ continue; } case lltok::kw_byval: B.addAttribute(Attribute::ByVal); break; + case lltok::kw_dereferenceable: { + uint64_t Bytes; + if (ParseOptionalDereferenceableBytes(Bytes)) + return true; + B.addDereferenceableAttr(Bytes); + continue; + } case lltok::kw_inalloca: B.addAttribute(Attribute::InAlloca); break; case lltok::kw_inreg: B.addAttribute(Attribute::InReg); break; case lltok::kw_nest: B.addAttribute(Attribute::Nest); break; @@ -1341,6 +1359,13 @@ switch (Token) { default: // End of attributes. return HaveError; + case lltok::kw_dereferenceable: { + uint64_t Bytes; + if (ParseOptionalDereferenceableBytes(Bytes)) + return true; + B.addDereferenceableAttr(Bytes); + continue; + } case lltok::kw_inreg: B.addAttribute(Attribute::InReg); break; case lltok::kw_noalias: B.addAttribute(Attribute::NoAlias); break; case lltok::kw_nonnull: B.addAttribute(Attribute::NonNull); break; @@ -1606,6 +1631,26 @@ return false; } +/// ParseOptionalDereferenceableBytes +/// ::= /* empty */ +/// ::= 'dereferenceable' '(' 4 ')' +bool LLParser::ParseOptionalDereferenceableBytes(uint64_t &Bytes) { + Bytes = 0; + if (!EatIfPresent(lltok::kw_dereferenceable)) + return false; + LocTy ParenLoc = Lex.getLoc(); + if (!EatIfPresent(lltok::lparen)) + return Error(ParenLoc, "expected '('"); + LocTy DerefLoc = Lex.getLoc(); + if (ParseUInt64(Bytes)) return true; + ParenLoc = Lex.getLoc(); + if (!EatIfPresent(lltok::rparen)) + return Error(ParenLoc, "expected ')'"); + if (!Bytes) + return Error(DerefLoc, "dereferenceable bytes must be non-zero"); + return false; +} + /// ParseOptionalCommaAlign /// ::= /// ::= ',' align 4 Index: lib/AsmParser/LLToken.h =================================================================== --- lib/AsmParser/LLToken.h +++ lib/AsmParser/LLToken.h @@ -106,6 +106,7 @@ kw_byval, kw_inalloca, kw_cold, + kw_dereferenceable, kw_inlinehint, kw_inreg, kw_jumptable, Index: lib/Bitcode/Reader/BitcodeReader.cpp =================================================================== --- lib/Bitcode/Reader/BitcodeReader.cpp +++ lib/Bitcode/Reader/BitcodeReader.cpp @@ -588,6 +588,8 @@ return Attribute::NonLazyBind; case bitc::ATTR_KIND_NON_NULL: return Attribute::NonNull; + case bitc::ATTR_KIND_DEFERERENCEABLE: + return Attribute::Dereferenceable; case bitc::ATTR_KIND_NO_RED_ZONE: return Attribute::NoRedZone; case bitc::ATTR_KIND_NO_RETURN: @@ -689,8 +691,10 @@ return EC; if (Kind == Attribute::Alignment) B.addAlignmentAttr(Record[++i]); - else + else if (Kind == Attribute::StackAlignment) B.addStackAlignmentAttr(Record[++i]); + else if (Kind == Attribute::Dereferenceable) + B.addDereferenceableAttr(Record[++i]); } else { // String attribute assert((Record[i] == 3 || Record[i] == 4) && "Invalid attribute group entry"); Index: lib/Bitcode/Writer/BitcodeWriter.cpp =================================================================== --- lib/Bitcode/Writer/BitcodeWriter.cpp +++ lib/Bitcode/Writer/BitcodeWriter.cpp @@ -201,6 +201,8 @@ return bitc::ATTR_KIND_NON_LAZY_BIND; case Attribute::NonNull: return bitc::ATTR_KIND_NON_NULL; + case Attribute::Dereferenceable: + return bitc::ATTR_KIND_DEFERERENCEABLE; case Attribute::NoRedZone: return bitc::ATTR_KIND_NO_RED_ZONE; case Attribute::NoReturn: @@ -272,7 +274,7 @@ if (Attr.isEnumAttribute()) { Record.push_back(0); Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum())); - } else if (Attr.isAlignAttribute()) { + } else if (Attr.isIntAttribute()) { Record.push_back(1); Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum())); Record.push_back(Attr.getValueAsInt()); Index: lib/IR/AttributeImpl.h =================================================================== --- lib/IR/AttributeImpl.h +++ lib/IR/AttributeImpl.h @@ -39,7 +39,7 @@ protected: enum AttrEntryKind { EnumAttrEntry, - AlignAttrEntry, + IntAttrEntry, StringAttrEntry }; @@ -49,7 +49,7 @@ virtual ~AttributeImpl(); bool isEnumAttribute() const { return KindID == EnumAttrEntry; } - bool isAlignAttribute() const { return KindID == AlignAttrEntry; } + bool isIntAttribute() const { return KindID == IntAttrEntry; } bool isStringAttribute() const { return KindID == StringAttrEntry; } bool hasAttribute(Attribute::AttrKind A) const; @@ -67,7 +67,7 @@ void Profile(FoldingSetNodeID &ID) const { if (isEnumAttribute()) Profile(ID, getKindAsEnum(), 0); - else if (isAlignAttribute()) + else if (isIntAttribute()) Profile(ID, getKindAsEnum(), getValueAsInt()); else Profile(ID, getKindAsString(), getValueAsString()); @@ -108,19 +108,20 @@ Attribute::AttrKind getEnumKind() const { return Kind; } }; -class AlignAttributeImpl : public EnumAttributeImpl { +class IntAttributeImpl : public EnumAttributeImpl { void anchor() override; - unsigned Align; + uint64_t Val; public: - AlignAttributeImpl(Attribute::AttrKind Kind, unsigned Align) - : EnumAttributeImpl(AlignAttrEntry, Kind), Align(Align) { + IntAttributeImpl(Attribute::AttrKind Kind, uint64_t Val) + : EnumAttributeImpl(IntAttrEntry, Kind), Val(Val) { assert( - (Kind == Attribute::Alignment || Kind == Attribute::StackAlignment) && - "Wrong kind for alignment attribute!"); + (Kind == Attribute::Alignment || Kind == Attribute::StackAlignment || + Kind == Attribute::Dereferenceable) && + "Wrong kind for int attribute!"); } - unsigned getAlignment() const { return Align; } + uint64_t getValue() const { return Val; } }; class StringAttributeImpl : public AttributeImpl { @@ -164,6 +165,7 @@ unsigned getAlignment() const; unsigned getStackAlignment() const; + uint64_t getDereferenceableBytes() const; std::string getAsString(bool InAttrGrp) const; typedef const Attribute *iterator; Index: lib/IR/Attributes.cpp =================================================================== --- lib/IR/Attributes.cpp +++ lib/IR/Attributes.cpp @@ -47,7 +47,7 @@ if (!Val) PA = new EnumAttributeImpl(Kind); else - PA = new AlignAttributeImpl(Kind, Val); + PA = new IntAttributeImpl(Kind, Val); pImpl->AttrsSet.InsertNode(PA, InsertPoint); } @@ -88,6 +88,12 @@ return get(Context, StackAlignment, Align); } +Attribute Attribute::getWithDereferenceableBytes(LLVMContext &Context, + uint64_t Bytes) { + assert(Bytes && "Bytes must be positive."); + return get(Context, Dereferenceable, Bytes); +} + //===----------------------------------------------------------------------===// // Attribute Accessor Methods //===----------------------------------------------------------------------===// @@ -96,8 +102,8 @@ return pImpl && pImpl->isEnumAttribute(); } -bool Attribute::isAlignAttribute() const { - return pImpl && pImpl->isAlignAttribute(); +bool Attribute::isIntAttribute() const { + return pImpl && pImpl->isIntAttribute(); } bool Attribute::isStringAttribute() const { @@ -106,15 +112,15 @@ Attribute::AttrKind Attribute::getKindAsEnum() const { if (!pImpl) return None; - assert((isEnumAttribute() || isAlignAttribute()) && + assert((isEnumAttribute() || isIntAttribute()) && "Invalid attribute type to get the kind as an enum!"); return pImpl ? pImpl->getKindAsEnum() : None; } uint64_t Attribute::getValueAsInt() const { if (!pImpl) return 0; - assert(isAlignAttribute() && - "Expected the attribute to be an alignment attribute!"); + assert(isIntAttribute() && + "Expected the attribute to be an integer attribute!"); return pImpl ? pImpl->getValueAsInt() : 0; } @@ -156,6 +162,14 @@ return pImpl->getValueAsInt(); } +/// This returns the number of dereferenceable bytes. +uint64_t Attribute::getDereferenceableBytes() const { + assert(hasAttribute(Attribute::Dereferenceable) && + "Trying to get dereferenceable bytes from " + "non-dereferenceable attribute!"); + return pImpl->getValueAsInt(); +} + std::string Attribute::getAsString(bool InAttrGrp) const { if (!pImpl) return ""; @@ -263,6 +277,20 @@ return Result; } + if (hasAttribute(Attribute::Dereferenceable)) { + std::string Result; + Result += "dereferenceable"; + if (InAttrGrp) { + Result += "="; + Result += utostr(getValueAsInt()); + } else { + Result += "("; + Result += utostr(getValueAsInt()); + Result += ")"; + } + return Result; + } + // Convert target-dependent attributes to strings of the form: // // "kind" @@ -296,7 +324,7 @@ // Pin the vtables to this file. AttributeImpl::~AttributeImpl() {} void EnumAttributeImpl::anchor() {} -void AlignAttributeImpl::anchor() {} +void IntAttributeImpl::anchor() {} void StringAttributeImpl::anchor() {} bool AttributeImpl::hasAttribute(Attribute::AttrKind A) const { @@ -310,13 +338,13 @@ } Attribute::AttrKind AttributeImpl::getKindAsEnum() const { - assert(isEnumAttribute() || isAlignAttribute()); + assert(isEnumAttribute() || isIntAttribute()); return static_cast(this)->getEnumKind(); } uint64_t AttributeImpl::getValueAsInt() const { - assert(isAlignAttribute()); - return static_cast(this)->getAlignment(); + assert(isIntAttribute()); + return static_cast(this)->getValue(); } StringRef AttributeImpl::getKindAsString() const { @@ -334,18 +362,18 @@ // relative to their enum value) and then strings. if (isEnumAttribute()) { if (AI.isEnumAttribute()) return getKindAsEnum() < AI.getKindAsEnum(); - if (AI.isAlignAttribute()) return true; + if (AI.isIntAttribute()) return true; if (AI.isStringAttribute()) return true; } - if (isAlignAttribute()) { + if (isIntAttribute()) { if (AI.isEnumAttribute()) return false; - if (AI.isAlignAttribute()) return getValueAsInt() < AI.getValueAsInt(); + if (AI.isIntAttribute()) return getValueAsInt() < AI.getValueAsInt(); if (AI.isStringAttribute()) return true; } if (AI.isEnumAttribute()) return false; - if (AI.isAlignAttribute()) return false; + if (AI.isIntAttribute()) return false; if (getKindAsString() == AI.getKindAsString()) return getValueAsString() < AI.getValueAsString(); return getKindAsString() < AI.getKindAsString(); @@ -398,6 +426,8 @@ case Attribute::InAlloca: return 1ULL << 43; case Attribute::NonNull: return 1ULL << 44; case Attribute::JumpTable: return 1ULL << 45; + case Attribute::Dereferenceable: + llvm_unreachable("dereferenceable attribute not supported in raw format"); } llvm_unreachable("Unsupported attribute type"); } @@ -482,6 +512,13 @@ return 0; } +uint64_t AttributeSetNode::getDereferenceableBytes() const { + for (iterator I = begin(), E = end(); I != E; ++I) + if (I->hasAttribute(Attribute::Dereferenceable)) + return I->getDereferenceableBytes(); + return 0; +} + std::string AttributeSetNode::getAsString(bool InAttrGrp) const { std::string Str; for (iterator I = begin(), E = end(); I != E; ++I) { @@ -515,6 +552,8 @@ Mask |= (Log2_32(ASN->getAlignment()) + 1) << 16; else if (Kind == Attribute::StackAlignment) Mask |= (Log2_32(ASN->getStackAlignment()) + 1) << 26; + else if (Kind == Attribute::Dereferenceable) + llvm_unreachable("dereferenceable not supported in bit mask"); else Mask |= AttributeImpl::getAttrMask(Kind); } @@ -620,6 +659,10 @@ else if (Kind == Attribute::StackAlignment) Attrs.push_back(std::make_pair(Index, Attribute:: getWithStackAlignment(C, B.getStackAlignment()))); + else if (Kind == Attribute::Dereferenceable) + Attrs.push_back(std::make_pair(Index, + Attribute::getWithDereferenceableBytes(C, + B.getDereferenceableBytes()))); else Attrs.push_back(std::make_pair(Index, Attribute::get(C, Kind))); } @@ -877,6 +920,11 @@ return ASN ? ASN->getStackAlignment() : 0; } +uint64_t AttributeSet::getDereferenceableBytes(unsigned Index) const { + AttributeSetNode *ASN = getAttributes(Index); + return ASN ? ASN->getDereferenceableBytes() : 0; +} + std::string AttributeSet::getAsString(unsigned Index, bool InAttrGrp) const { AttributeSetNode *ASN = getAttributes(Index); @@ -956,7 +1004,7 @@ //===----------------------------------------------------------------------===// AttrBuilder::AttrBuilder(AttributeSet AS, unsigned Index) - : Attrs(0), Alignment(0), StackAlignment(0) { + : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) { AttributeSetImpl *pImpl = AS.pImpl; if (!pImpl) return; @@ -973,13 +1021,14 @@ void AttrBuilder::clear() { Attrs.reset(); - Alignment = StackAlignment = 0; + Alignment = StackAlignment = DerefBytes = 0; } AttrBuilder &AttrBuilder::addAttribute(Attribute::AttrKind Val) { assert((unsigned)Val < Attribute::EndAttrKinds && "Attribute out of range!"); assert(Val != Attribute::Alignment && Val != Attribute::StackAlignment && - "Adding alignment attribute without adding alignment value!"); + Val != Attribute::Dereferenceable && + "Adding integer attribute without adding a value!"); Attrs[Val] = true; return *this; } @@ -997,6 +1046,8 @@ Alignment = Attr.getAlignment(); else if (Kind == Attribute::StackAlignment) StackAlignment = Attr.getStackAlignment(); + else if (Kind == Attribute::Dereferenceable) + DerefBytes = Attr.getDereferenceableBytes(); return *this; } @@ -1013,6 +1064,8 @@ Alignment = 0; else if (Val == Attribute::StackAlignment) StackAlignment = 0; + else if (Val == Attribute::Dereferenceable) + DerefBytes = 0; return *this; } @@ -1029,7 +1082,7 @@ for (AttributeSet::iterator I = A.begin(Slot), E = A.end(Slot); I != E; ++I) { Attribute Attr = *I; - if (Attr.isEnumAttribute() || Attr.isAlignAttribute()) { + if (Attr.isEnumAttribute() || Attr.isIntAttribute()) { Attribute::AttrKind Kind = I->getKindAsEnum(); Attrs[Kind] = false; @@ -1037,6 +1090,8 @@ Alignment = 0; else if (Kind == Attribute::StackAlignment) StackAlignment = 0; + else if (Kind == Attribute::Dereferenceable) + DerefBytes = 0; } else { assert(Attr.isStringAttribute() && "Invalid attribute type!"); std::map::iterator @@ -1079,6 +1134,14 @@ return *this; } +AttrBuilder &AttrBuilder::addDereferenceableAttr(uint64_t Bytes) { + if (Bytes == 0) return *this; + + Attrs[Attribute::Dereferenceable] = true; + DerefBytes = Bytes; + return *this; +} + AttrBuilder &AttrBuilder::merge(const AttrBuilder &B) { // FIXME: What if both have alignments, but they don't match?! if (!Alignment) @@ -1087,6 +1150,9 @@ if (!StackAlignment) StackAlignment = B.StackAlignment; + if (!DerefBytes) + DerefBytes = B.DerefBytes; + Attrs |= B.Attrs; for (td_const_iterator I = B.TargetDepAttrs.begin(), @@ -1117,7 +1183,7 @@ for (AttributeSet::iterator I = A.begin(Slot), E = A.end(Slot); I != E; ++I) { Attribute Attr = *I; - if (Attr.isEnumAttribute() || Attr.isAlignAttribute()) { + if (Attr.isEnumAttribute() || Attr.isIntAttribute()) { if (Attrs[I->getKindAsEnum()]) return true; } else { @@ -1142,7 +1208,8 @@ if (B.TargetDepAttrs.find(I->first) == B.TargetDepAttrs.end()) return false; - return Alignment == B.Alignment && StackAlignment == B.StackAlignment; + return Alignment == B.Alignment && StackAlignment == B.StackAlignment && + DerefBytes == B.DerefBytes; } AttrBuilder &AttrBuilder::addRawValue(uint64_t Val) { @@ -1151,6 +1218,8 @@ for (Attribute::AttrKind I = Attribute::None; I != Attribute::EndAttrKinds; I = Attribute::AttrKind(I + 1)) { + if (I == Attribute::Dereferenceable) + continue; if (uint64_t A = (Val & AttributeImpl::getAttrMask(I))) { Attrs[I] = true; @@ -1184,6 +1253,7 @@ .addAttribute(Attribute::NoAlias) .addAttribute(Attribute::NoCapture) .addAttribute(Attribute::NonNull) + .addDereferenceableAttr(1) // the int here is ignored .addAttribute(Attribute::ReadNone) .addAttribute(Attribute::ReadOnly) .addAttribute(Attribute::StructRet) Index: lib/IR/Function.cpp =================================================================== --- lib/IR/Function.cpp +++ lib/IR/Function.cpp @@ -77,11 +77,17 @@ } /// hasNonNullAttr - Return true if this argument has the nonnull attribute on -/// it in its containing function. +/// it in its containing function. Also returns true if at least one byte is +/// known to be dereferenceable and the pointer is in addrspace(0). bool Argument::hasNonNullAttr() const { if (!getType()->isPointerTy()) return false; - return getParent()->getAttributes(). - hasAttribute(getArgNo()+1, Attribute::NonNull); + if (getParent()->getAttributes(). + hasAttribute(getArgNo()+1, Attribute::NonNull)) + return true; + else if (getDereferenceableBytes() > 0 && + getType()->getPointerAddressSpace() == 0) + return true; + return false; } /// hasByValAttr - Return true if this argument has the byval attribute on it @@ -113,6 +119,12 @@ } +uint64_t Argument::getDereferenceableBytes() const { + assert(getType()->isPointerTy() && + "Only pointers have dereferenceable bytes"); + return getParent()->getDereferenceableBytes(getArgNo()+1); +} + /// hasNestAttr - Return true if this argument has the nest attribute on /// it in its containing function. bool Argument::hasNestAttr() const { Index: lib/IR/Value.cpp =================================================================== --- lib/IR/Value.cpp +++ lib/IR/Value.cpp @@ -15,6 +15,7 @@ #include "LLVMContextImpl.h" #include "llvm/ADT/DenseMap.h" #include "llvm/ADT/SmallString.h" +#include "llvm/IR/CallSite.h" #include "llvm/IR/Constant.h" #include "llvm/IR/Constants.h" #include "llvm/IR/DataLayout.h" @@ -504,9 +505,29 @@ if (const GlobalVariable *GV = dyn_cast(V)) return !GV->hasExternalWeakLinkage(); - // byval arguments are ok. - if (const Argument *A = dyn_cast(V)) - return A->hasByValAttr(); + // byval arguments are okay. Arguments specifically marked as + // dereferenceable are okay too. + if (const Argument *A = dyn_cast(V)) { + if (A->hasByValAttr()) + return true; + else if (uint64_t Bytes = A->getDereferenceableBytes()) { + Type *Ty = V->getType()->getPointerElementType(); + if (Ty->isSized() && DL && DL->getTypeStoreSize(Ty) <= Bytes) + return true; + } + + return false; + } + + // Return values from call sites specifically marked as dereferenceable are + // also okay. + if (ImmutableCallSite CS = V) { + if (uint64_t Bytes = CS.getDereferenceableBytes(0)) { + Type *Ty = V->getType()->getPointerElementType(); + if (Ty->isSized() && DL && DL->getTypeStoreSize(Ty) <= Bytes) + return true; + } + } // For GEPs, determine if the indexing lands within the allocated object. if (const GEPOperator *GEP = dyn_cast(V)) { Index: test/Bitcode/attributes.ll =================================================================== --- test/Bitcode/attributes.ll +++ test/Bitcode/attributes.ll @@ -229,6 +229,16 @@ unreachable } +define dereferenceable(2) i8* @f39(i8* dereferenceable(1) %a) { +; CHECK: define dereferenceable(2) i8* @f39(i8* dereferenceable(1) %a) { + ret i8* %a +} + +define dereferenceable(18446744073709551606) i8* @f40(i8* dereferenceable(18446744073709551615) %a) { +; CHECK: define dereferenceable(18446744073709551606) i8* @f40(i8* dereferenceable(18446744073709551615) %a) { + ret i8* %a +} + ; CHECK: attributes #0 = { noreturn } ; CHECK: attributes #1 = { nounwind } ; CHECK: attributes #2 = { readnone } Index: test/Transforms/InstSimplify/compare.ll =================================================================== --- test/Transforms/InstSimplify/compare.ll +++ test/Transforms/InstSimplify/compare.ll @@ -874,6 +874,21 @@ ; CHECK: ret i1 false } +define i1 @nonnull_deref_arg(i32* dereferenceable(4) %i) { + %cmp = icmp eq i32* %i, null + ret i1 %cmp +; CHECK-LABEL: @nonnull_deref_arg +; CHECK: ret i1 false +} + +define i1 @nonnull_deref_as_arg(i32 addrspace(1)* dereferenceable(4) %i) { + %cmp = icmp eq i32 addrspace(1)* %i, null + ret i1 %cmp +; CHECK-LABEL: @nonnull_deref_as_arg +; CHECK: icmp +; CHECK ret +} + declare nonnull i32* @returns_nonnull_helper() define i1 @returns_nonnull() { %call = call nonnull i32* @returns_nonnull_helper() @@ -883,6 +898,25 @@ ; CHECK: ret i1 false } +declare dereferenceable(4) i32* @returns_nonnull_deref_helper() +define i1 @returns_nonnull_deref() { + %call = call dereferenceable(4) i32* @returns_nonnull_deref_helper() + %cmp = icmp eq i32* %call, null + ret i1 %cmp +; CHECK-LABEL: @returns_nonnull_deref +; CHECK: ret i1 false +} + +declare dereferenceable(4) i32 addrspace(1)* @returns_nonnull_deref_as_helper() +define i1 @returns_nonnull_as_deref() { + %call = call dereferenceable(4) i32 addrspace(1)* @returns_nonnull_deref_as_helper() + %cmp = icmp eq i32 addrspace(1)* %call, null + ret i1 %cmp +; CHECK-LABEL: @returns_nonnull_as_deref +; CHECK: icmp +; CHECK: ret +} + ; If a bit is known to be zero for A and known to be one for B, ; then A and B cannot be equal. define i1 @icmp_eq_const(i32 %a) nounwind { Index: test/Transforms/LICM/hoist-deref-load.ll =================================================================== --- /dev/null +++ test/Transforms/LICM/hoist-deref-load.ll @@ -0,0 +1,86 @@ +; RUN: opt -S -basicaa -licm < %s | FileCheck %s +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +; This test represents the following function: +; void test1(int * __restrict__ a, int * __restrict__ b, int &c, int n) { +; for (int i = 0; i < n; ++i) +; if (a[i] > 0) +; a[i] = c*b[i]; +; } +; and we want to hoist the load of %c out of the loop. This can be done only +; because the dereferenceable attribute is on %c. + +; CHECK-LABEL: @test1 +; CHECK: load i32* %c, align 4 +; CHECK: for.body: + +define void @test1(i32* noalias nocapture %a, i32* noalias nocapture readonly %b, i32* nocapture readonly nonnull dereferenceable(4) %c, i32 %n) #0 { +entry: + %cmp11 = icmp sgt i32 %n, 0 + br i1 %cmp11, label %for.body, label %for.end + +for.body: ; preds = %entry, %for.inc + %indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ] + %arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv + %0 = load i32* %arrayidx, align 4 + %cmp1 = icmp sgt i32 %0, 0 + br i1 %cmp1, label %if.then, label %for.inc + +if.then: ; preds = %for.body + %1 = load i32* %c, align 4 + %arrayidx3 = getelementptr inbounds i32* %b, i64 %indvars.iv + %2 = load i32* %arrayidx3, align 4 + %mul = mul nsw i32 %2, %1 + store i32 %mul, i32* %arrayidx, align 4 + br label %for.inc + +for.inc: ; preds = %for.body, %if.then + %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 + %lftr.wideiv = trunc i64 %indvars.iv.next to i32 + %exitcond = icmp eq i32 %lftr.wideiv, %n + br i1 %exitcond, label %for.end, label %for.body + +for.end: ; preds = %for.inc, %entry + ret void +} + +; This is the same as @test1, but without the dereferenceable attribute on %c. +; Without this attribute, we should not hoist the load of %c. + +; CHECK-LABEL: @test2 +; CHECK: if.then: +; CHECK: load i32* %c, align 4 + +define void @test2(i32* noalias nocapture %a, i32* noalias nocapture readonly %b, i32* nocapture readonly nonnull %c, i32 %n) #0 { +entry: + %cmp11 = icmp sgt i32 %n, 0 + br i1 %cmp11, label %for.body, label %for.end + +for.body: ; preds = %entry, %for.inc + %indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ] + %arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv + %0 = load i32* %arrayidx, align 4 + %cmp1 = icmp sgt i32 %0, 0 + br i1 %cmp1, label %if.then, label %for.inc + +if.then: ; preds = %for.body + %1 = load i32* %c, align 4 + %arrayidx3 = getelementptr inbounds i32* %b, i64 %indvars.iv + %2 = load i32* %arrayidx3, align 4 + %mul = mul nsw i32 %2, %1 + store i32 %mul, i32* %arrayidx, align 4 + br label %for.inc + +for.inc: ; preds = %for.body, %if.then + %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 + %lftr.wideiv = trunc i64 %indvars.iv.next to i32 + %exitcond = icmp eq i32 %lftr.wideiv, %n + br i1 %exitcond, label %for.end, label %for.body + +for.end: ; preds = %for.inc, %entry + ret void +} + +attributes #0 = { nounwind uwtable } +