diff options
| -rw-r--r-- | llvm/lib/Bitcode/Reader/MetadataLoader.cpp | 67 |
1 files changed, 23 insertions, 44 deletions
diff --git a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp index 8cec349af30..595b9837c1d 100644 --- a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp +++ b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp @@ -97,25 +97,20 @@ namespace { static int64_t unrotateSign(uint64_t U) { return U & 1 ? ~(U >> 1) : U >> 1; } class BitcodeReaderMetadataList { - /// Keep track of the current number of ForwardReference in the list. - unsigned NumFwdRefs = 0; - /// Maintain the range [min-max] that needs to be inspected to resolve cycles. - /// This is the range of Metadata that have involved forward reference during - /// loading and that needs to be inspected to resolve cycles. It is purely an - /// optimization to avoid spending time resolving cycles outside of this - /// range, i.e. where there hasn't been any forward reference. - unsigned MinFwdRef = 0; - unsigned MaxFwdRef = 0; - /// Set to true if there was any FwdRef encountered. This is used to track if - /// we need to resolve cycles after loading metadatas. - bool AnyFwdRefs = false; - /// Array of metadata references. /// /// Don't use std::vector here. Some versions of libc++ copy (instead of /// move) on resize, and TrackingMDRef is very expensive to copy. SmallVector<TrackingMDRef, 1> MetadataPtrs; + /// The set of indices in MetadataPtrs above of forward references that were + /// generated. + SmallDenseSet<unsigned, 1> ForwardReference; + + /// The set of indices in MetadataPtrs above of Metadata that need to be + /// resolved. + SmallDenseSet<unsigned, 1> UnresolvedNodes; + /// Structures for resolving old type refs. struct { SmallDenseMap<MDString *, TempMDTuple, 1> Unknown; @@ -151,7 +146,8 @@ public: void shrinkTo(unsigned N) { assert(N <= size() && "Invalid shrinkTo request!"); - assert(!AnyFwdRefs && "Unexpected forward refs"); + assert(ForwardReference.empty() && "Unexpected forward refs"); + assert(UnresolvedNodes.empty() && "Unexpected unresolved node"); MetadataPtrs.resize(N); } @@ -168,7 +164,7 @@ public: MDNode *getMDNodeFwdRefOrNull(unsigned Idx); void assignValue(Metadata *MD, unsigned Idx); void tryToResolveCycles(); - bool hasFwdRefs() const { return AnyFwdRefs; } + bool hasFwdRefs() const { return !ForwardReference.empty(); } /// Upgrade a type that had an MDString reference. void addTypeRef(MDString &UUID, DICompositeType &CT); @@ -184,6 +180,10 @@ private: }; void BitcodeReaderMetadataList::assignValue(Metadata *MD, unsigned Idx) { + if (auto *MDN = dyn_cast<MDNode>(MD)) + if (!MDN->isResolved()) + UnresolvedNodes.insert(Idx); + if (Idx == size()) { push_back(MD); return; @@ -201,7 +201,7 @@ void BitcodeReaderMetadataList::assignValue(Metadata *MD, unsigned Idx) { // If there was a forward reference to this value, replace it. TempMDTuple PrevMD(cast<MDTuple>(OldMD.get())); PrevMD->replaceAllUsesWith(MD); - --NumFwdRefs; + ForwardReference.erase(Idx); } Metadata *BitcodeReaderMetadataList::getMetadataFwdRef(unsigned Idx) { @@ -212,14 +212,7 @@ Metadata *BitcodeReaderMetadataList::getMetadataFwdRef(unsigned Idx) { return MD; // Track forward refs to be resolved later. - if (AnyFwdRefs) { - MinFwdRef = std::min(MinFwdRef, Idx); - MaxFwdRef = std::max(MaxFwdRef, Idx); - } else { - AnyFwdRefs = true; - MinFwdRef = MaxFwdRef = Idx; - } - ++NumFwdRefs; + ForwardReference.insert(Idx); // Create and return a placeholder, which will later be RAUW'd. Metadata *MD = MDNode::getTemporary(Context, None).release(); @@ -240,12 +233,10 @@ MDNode *BitcodeReaderMetadataList::getMDNodeFwdRefOrNull(unsigned Idx) { } void BitcodeReaderMetadataList::tryToResolveCycles() { - if (NumFwdRefs) + if (!ForwardReference.empty()) // Still forward references... can't resolve cycles. return; - bool DidReplaceTypeRefs = false; - // Give up on finding a full definition for any forward decls that remain. for (const auto &Ref : OldTypeRefs.FwdDecls) OldTypeRefs.Final.insert(Ref); @@ -253,17 +244,14 @@ void BitcodeReaderMetadataList::tryToResolveCycles() { // Upgrade from old type ref arrays. In strange cases, this could add to // OldTypeRefs.Unknown. - for (const auto &Array : OldTypeRefs.Arrays) { - DidReplaceTypeRefs = true; + for (const auto &Array : OldTypeRefs.Arrays) Array.second->replaceAllUsesWith(resolveTypeRefArray(Array.first.get())); - } OldTypeRefs.Arrays.clear(); // Replace old string-based type refs with the resolved node, if possible. // If we haven't seen the node, leave it to the verifier to complain about // the invalid string reference. for (const auto &Ref : OldTypeRefs.Unknown) { - DidReplaceTypeRefs = true; if (DICompositeType *CT = OldTypeRefs.Final.lookup(Ref.first)) Ref.second->replaceAllUsesWith(CT); else @@ -271,19 +259,12 @@ void BitcodeReaderMetadataList::tryToResolveCycles() { } OldTypeRefs.Unknown.clear(); - // Make sure all the upgraded types are resolved. - if (DidReplaceTypeRefs) { - AnyFwdRefs = true; - MinFwdRef = 0; - MaxFwdRef = MetadataPtrs.size() - 1; - } - - if (!AnyFwdRefs) + if (UnresolvedNodes.empty()) // Nothing to do. return; // Resolve any cycles. - for (unsigned I = MinFwdRef, E = MaxFwdRef + 1; I != E; ++I) { + for (unsigned I : UnresolvedNodes) { auto &MD = MetadataPtrs[I]; auto *N = dyn_cast_or_null<MDNode>(MD); if (!N) @@ -293,10 +274,8 @@ void BitcodeReaderMetadataList::tryToResolveCycles() { N->resolveCycles(); } - // Make sure we return early again until there's another forward ref. - AnyFwdRefs = false; - MinFwdRef = 0; - MaxFwdRef = 0; + // Make sure we return early again until there's another unresolved ref. + UnresolvedNodes.clear(); } void BitcodeReaderMetadataList::addTypeRef(MDString &UUID, |
