r266160 - [modules] Refactor handling of cases where we write an offset to a prior record into the bitstream and simplify a little, in preparation for doing this in more cases.
Nico Weber via cfe-commits
cfe-commits at lists.llvm.org
Thu Apr 14 09:00:31 PDT 2016
On Wed, Apr 13, 2016 at 10:24 PM, Nico Weber <thakis at chromium.org> wrote:
> On Tue, Apr 12, 2016 at 10:12 PM, Richard Smith via cfe-commits <
> cfe-commits at lists.llvm.org> wrote:
>
>> Author: rsmith
>> Date: Tue Apr 12 21:12:03 2016
>> New Revision: 266160
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=266160&view=rev
>> Log:
>> [modules] Refactor handling of cases where we write an offset to a prior
>> record into the bitstream and simplify a little, in preparation for doing
>> this in more cases.
>>
>> Modified:
>> cfe/trunk/include/clang/Serialization/ASTWriter.h
>> cfe/trunk/lib/Serialization/ASTWriter.cpp
>> cfe/trunk/lib/Serialization/ASTWriterDecl.cpp
>>
>> Modified: cfe/trunk/include/clang/Serialization/ASTWriter.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Serialization/ASTWriter.h?rev=266160&r1=266159&r2=266160&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/include/clang/Serialization/ASTWriter.h (original)
>> +++ cfe/trunk/include/clang/Serialization/ASTWriter.h Tue Apr 12 21:12:03
>> 2016
>> @@ -787,11 +787,29 @@ class ASTRecordWriter {
>> /// declaration or type.
>> SmallVector<Stmt *, 16> StmtsToEmit;
>>
>> + static constexpr int MaxOffsetIndices = 4;
>> + /// \brief Indices of record elements that describe offsets within the
>> + /// bitcode. These will be converted to offsets relative to the current
>> + /// record when emitted.
>> + unsigned OffsetIndices[MaxOffsetIndices];
>> + unsigned NumOffsetIndices = 0;
>> +
>> /// \brief Flush all of the statements and expressions that have
>> /// been added to the queue via AddStmt().
>> void FlushStmts();
>> void FlushSubStmts();
>>
>> + void PrepareToEmit(uint64_t MyOffset) {
>> + // Convert offsets into relative form.
>> + for (unsigned I = 0; I != NumOffsetIndices; ++I) {
>> + auto &StoredOffset = (*Record)[OffsetIndices[I]];
>> + assert(StoredOffset < MyOffset && "invalid offset");
>> + if (StoredOffset)
>> + StoredOffset = MyOffset - StoredOffset;
>> + }
>> + NumOffsetIndices = 0;
>> + }
>> +
>> public:
>> /// Construct a ASTRecordWriter that uses the default encoding scheme.
>> ASTRecordWriter(ASTWriter &Writer, ASTWriter::RecordDataImpl &Record)
>> @@ -802,6 +820,10 @@ public:
>> ASTRecordWriter(ASTRecordWriter &Parent, ASTWriter::RecordDataImpl
>> &Record)
>> : Writer(Parent.Writer), Record(&Record) {}
>>
>> + /// Copying an ASTRecordWriter is almost certainly a bug.
>> + ASTRecordWriter(const ASTRecordWriter&) = delete;
>> + void operator=(const ASTRecordWriter&) = delete;
>> +
>> /// \brief Extract the underlying record storage.
>> ASTWriter::RecordDataImpl &getRecordData() const { return *Record; }
>>
>> @@ -822,6 +844,7 @@ public:
>> // FIXME: Allow record producers to suggest Abbrevs.
>> uint64_t Emit(unsigned Code, unsigned Abbrev = 0) {
>> uint64_t Offset = Writer->Stream.GetCurrentBitNo();
>> + PrepareToEmit(Offset);
>> Writer->Stream.EmitRecord(Code, *Record, Abbrev);
>> FlushStmts();
>> return Offset;
>> @@ -830,10 +853,19 @@ public:
>> /// \brief Emit the record to the stream, preceded by its
>> substatements.
>> uint64_t EmitStmt(unsigned Code, unsigned Abbrev = 0) {
>> FlushSubStmts();
>> + PrepareToEmit(Writer->Stream.GetCurrentBitNo());
>> Writer->Stream.EmitRecord(Code, *Record, Abbrev);
>> return Writer->Stream.GetCurrentBitNo();
>> }
>>
>> + /// \brief Add a bit offset into the record. This will be converted
>> into an
>> + /// offset relative to the current record when emitted.
>> + void AddOffset(uint64_t BitOffset) {
>> + assert(NumOffsetIndices != MaxOffsetIndices && "too many offset
>> indices");
>>
>
> This assert is firing when building chrome with clang-cl on Windows:
> https://build.chromium.org/p/chromium.fyi/builders/ClangToTWin%28dbg%29/builds/5340/steps/compile/logs/stdio
>
Repro: https://llvm.org/bugs/show_bug.cgi?id=27351
>
>
>> + OffsetIndices[NumOffsetIndices++] = Record->size();
>> + Record->push_back(BitOffset);
>> + }
>> +
>> /// \brief Add the given statement or expression to the queue of
>> /// statements to emit.
>> ///
>>
>> Modified: cfe/trunk/lib/Serialization/ASTWriter.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTWriter.cpp?rev=266160&r1=266159&r2=266160&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/Serialization/ASTWriter.cpp (original)
>> +++ cfe/trunk/lib/Serialization/ASTWriter.cpp Tue Apr 12 21:12:03 2016
>> @@ -4694,6 +4694,7 @@ void ASTWriter::WriteDeclUpdatesBlocks(R
>> auto *RD = cast<CXXRecordDecl>(D);
>> UpdatedDeclContexts.insert(RD->getPrimaryContext());
>> Record.AddCXXDefinitionData(RD);
>> + // FIXME: Use AddOffset here.
>> Record.push_back(WriteDeclContextLexicalBlock(
>> *Context, const_cast<CXXRecordDecl *>(RD)));
>>
>>
>> Modified: cfe/trunk/lib/Serialization/ASTWriterDecl.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTWriterDecl.cpp?rev=266160&r1=266159&r2=266160&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/Serialization/ASTWriterDecl.cpp (original)
>> +++ cfe/trunk/lib/Serialization/ASTWriterDecl.cpp Tue Apr 12 21:12:03 2016
>> @@ -125,8 +125,7 @@ namespace clang {
>> void VisitCapturedDecl(CapturedDecl *D);
>> void VisitEmptyDecl(EmptyDecl *D);
>>
>> - void VisitDeclContext(DeclContext *DC, uint64_t LexicalOffset,
>> - uint64_t VisibleOffset);
>> + void VisitDeclContext(DeclContext *DC);
>> template <typename T> void VisitRedeclarable(Redeclarable<T> *D);
>>
>>
>> @@ -149,12 +148,6 @@ namespace clang {
>> void VisitOMPDeclareReductionDecl(OMPDeclareReductionDecl *D);
>> void VisitOMPCapturedExprDecl(OMPCapturedExprDecl *D);
>>
>> - void AddLocalOffset(uint64_t LocalOffset) {
>> - uint64_t Offset = Writer.Stream.GetCurrentBitNo();
>> - assert(LocalOffset < Offset && "invalid offset");
>> - Record.push_back(LocalOffset ? Offset - LocalOffset : 0);
>> - }
>> -
>> /// Add an Objective-C type parameter list to the given record.
>> void AddObjCTypeParamList(ObjCTypeParamList *typeParams) {
>> // Empty type parameter list.
>> @@ -284,6 +277,12 @@ void ASTDeclWriter::Visit(Decl *D) {
>> if (FD->doesThisDeclarationHaveABody())
>> Record.AddFunctionDefinition(FD);
>> }
>> +
>> + // If this declaration is also a DeclContext, write blocks for the
>> + // declarations that lexically stored inside its context and those
>> + // declarations that are visible from its context.
>> + if (DeclContext *DC = dyn_cast<DeclContext>(D))
>> + VisitDeclContext(DC);
>> }
>>
>> void ASTDeclWriter::VisitDecl(Decl *D) {
>> @@ -1553,10 +1552,9 @@ void ASTDeclWriter::VisitStaticAssertDec
>> /// that there are no declarations visible from this context. Note
>> /// that this value will not be emitted for non-primary declaration
>> /// contexts.
>> -void ASTDeclWriter::VisitDeclContext(DeclContext *DC, uint64_t
>> LexicalOffset,
>> - uint64_t VisibleOffset) {
>> - AddLocalOffset(LexicalOffset);
>> - AddLocalOffset(VisibleOffset);
>> +void ASTDeclWriter::VisitDeclContext(DeclContext *DC) {
>> + Record.AddOffset(Writer.WriteDeclContextLexicalBlock(Context, DC));
>> + Record.AddOffset(Writer.WriteDeclContextVisibleBlock(Context, DC));
>> }
>>
>> const Decl *ASTWriter::getFirstLocalDecl(const Decl *D) {
>> @@ -1624,9 +1622,8 @@ void ASTDeclWriter::VisitRedeclarable(Re
>> // the declaration itself.
>> if (LocalRedecls.empty())
>> Record.push_back(0);
>> - else {
>> - AddLocalOffset(LocalRedeclWriter.Emit(LOCAL_REDECLARATIONS));
>> - }
>> + else
>> + Record.AddOffset(LocalRedeclWriter.Emit(LOCAL_REDECLARATIONS));
>> } else {
>> Record.push_back(0);
>> Record.AddDeclRef(FirstLocal);
>> @@ -2148,26 +2145,12 @@ void ASTWriter::WriteDecl(ASTContext &Co
>> ID = IDR;
>>
>> assert(ID >= FirstDeclID && "invalid decl ID");
>> -
>> - // If this declaration is also a DeclContext, write blocks for the
>> - // declarations that lexically stored inside its context and those
>> - // declarations that are visible from its context. These blocks
>> - // are written before the declaration itself so that we can put
>> - // their offsets into the record for the declaration.
>> - uint64_t LexicalOffset = 0;
>> - uint64_t VisibleOffset = 0;
>> - DeclContext *DC = dyn_cast<DeclContext>(D);
>> - if (DC) {
>> - LexicalOffset = WriteDeclContextLexicalBlock(Context, DC);
>> - VisibleOffset = WriteDeclContextVisibleBlock(Context, DC);
>> - }
>>
>> RecordData Record;
>> ASTDeclWriter W(*this, Context, Record);
>>
>> // Build a record for this declaration
>> W.Visit(D);
>> - if (DC) W.VisitDeclContext(DC, LexicalOffset, VisibleOffset);
>>
>> // Emit this declaration to the bitstream.
>> uint64_t Offset = W.Emit(D);
>>
>>
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>
>
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