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Function bitcode index in Value Symbol Table and lazy reading support

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Summary:
Support for including the function bitcode indices in the Value Symbol
Table. This requires writing the VST after the function blocks, which in
turn requires a new VST forward declaration record encoding the offset of
the full VST (which is backpatched to contain the offset after the VST
is written).

This patch also enables the lazy function reader to use the new function
indices out of the VST. This support will be used by ThinLTO as well, which
will be in a follow on patch. Backwards compatibility with older bitcode
files is maintained.

A new test is also included.

The bitcode format (used for the lazy reader as well as the upcoming
ThinLTO patches) came out of discussions with Duncan and others and is
described here:
https://drive.google.com/file/d/0B036uwnWM6RWdnBLakxmeDdOeXc/view

Reviewers: dexonsmith, davidxl, joker.eph

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12536

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247894 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Teresa Johnson 2015-09-17 15:52:30 +00:00
parent daaec40323
commit 1f05ba2fcb
5 changed files with 339 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
include/llvm/Bitcode/LLVMBitCodes.h
View File

@ -42,7 +42,10 @@ namespace bitc {
TYPE_BLOCK_ID_NEW,
USELIST_BLOCK_ID
USELIST_BLOCK_ID,
MODULE_STRTAB_BLOCK_ID,
FUNCTION_SUMMARY_BLOCK_ID
};
@ -73,6 +76,8 @@ namespace bitc {
MODULE_CODE_GCNAME = 11, // GCNAME: [strchr x N]
MODULE_CODE_COMDAT = 12, // COMDAT: [selection_kind, name]
MODULE_CODE_VSTOFFSET = 13, // VSTOFFSET: [offset]
};
/// PARAMATTR blocks have code for defining a parameter attribute set.
@ -131,10 +136,11 @@ namespace bitc {
TST_CODE_ENTRY = 1 // TST_ENTRY: [typeid, namechar x N]
};
// The value symbol table only has one code (VST_ENTRY_CODE).
// Value symbol table codes.
enum ValueSymtabCodes {
VST_CODE_ENTRY = 1, // VST_ENTRY: [valid, namechar x N]
VST_CODE_BBENTRY = 2 // VST_BBENTRY: [bbid, namechar x N]
VST_CODE_ENTRY = 1, // VST_ENTRY: [valueid, namechar x N]
VST_CODE_BBENTRY = 2, // VST_BBENTRY: [bbid, namechar x N]
VST_CODE_FNENTRY = 3, // VST_FNENTRY: [valueid, offset, namechar x N]
};
enum MetadataCodes {

166
lib/Bitcode/Reader/BitcodeReader.cpp
View File

@ -147,6 +147,7 @@ class BitcodeReader : public GVMaterializer {
BitstreamCursor Stream;
uint64_t NextUnreadBit = 0;
bool SeenValueSymbolTable = false;
unsigned VSTOffset = 0;
std::vector<Type*> TypeList;
BitcodeReaderValueList ValueList;
@ -370,7 +371,9 @@ private:
std::error_code parseTypeTable();
std::error_code parseTypeTableBody();
std::error_code parseValueSymbolTable();
ErrorOr<Value *> recordValue(SmallVectorImpl<uint64_t> &Record,
unsigned NameIndex, Triple &TT);
std::error_code parseValueSymbolTable(unsigned Offset = 0);
std::error_code parseConstants();
std::error_code rememberAndSkipFunctionBody();
/// Save the positions of the Metadata blocks and skip parsing the blocks.
@ -1583,7 +1586,61 @@ std::error_code BitcodeReader::parseTypeTableBody() {
}
}
std::error_code BitcodeReader::parseValueSymbolTable() {
/// Associate a value with its name from the given index in the provided record.
ErrorOr<Value *> BitcodeReader::recordValue(SmallVectorImpl<uint64_t> &Record,
unsigned NameIndex, Triple &TT) {
SmallString<128> ValueName;
if (convertToString(Record, NameIndex, ValueName))
return error("Invalid record");
unsigned ValueID = Record[0];
if (ValueID >= ValueList.size() || !ValueList[ValueID])
return error("Invalid record");
Value *V = ValueList[ValueID];
V->setName(StringRef(ValueName.data(), ValueName.size()));
auto *GO = dyn_cast<GlobalObject>(V);
if (GO) {
if (GO->getComdat() == reinterpret_cast<Comdat *>(1)) {
if (TT.isOSBinFormatMachO())
GO->setComdat(nullptr);
else
GO->setComdat(TheModule->getOrInsertComdat(V->getName()));
}
}
return V;
}
/// Parse the value symbol table at either the current parsing location or
/// at the given bit offset if provided.
std::error_code BitcodeReader::parseValueSymbolTable(unsigned Offset) {
uint64_t CurrentBit;
// Pass in the Offset to distinguish between calling for the module-level
// VST (where we want to jump to the VST offset) and the function-level
// VST (where we don't).
if (Offset > 0) {
// Save the current parsing location so we can jump back at the end
// of the VST read.
CurrentBit = Stream.GetCurrentBitNo();
Stream.JumpToBit(Offset * 32);
BitstreamEntry Entry = Stream.advance();
assert(Entry.Kind == BitstreamEntry::SubBlock);
assert(Entry.ID == bitc::VALUE_SYMTAB_BLOCK_ID);
}
// Compute the delta between the bitcode indices in the VST (the word offset
// to the word-aligned ENTER_SUBBLOCK for the function block, and that
// expected by the lazy reader. The reader's EnterSubBlock expects to have
// already read the ENTER_SUBBLOCK code (size getAbbrevIDWidth) and BlockID
// (size BlockIDWidth). Note that we access the stream's AbbrevID width here
// just before entering the VST subblock because: 1) the EnterSubBlock
// changes the AbbrevID width; 2) the VST block is nested within the same
// outer MODULE_BLOCK as the FUNCTION_BLOCKs and therefore have the same
// AbbrevID width before calling EnterSubBlock; and 3) when we want to
// jump to the FUNCTION_BLOCK using this offset later, we don't want
// to rely on the stream's AbbrevID width being that of the MODULE_BLOCK.
unsigned FuncBitcodeOffsetDelta =
Stream.getAbbrevIDWidth() + bitc::BlockIDWidth;
if (Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
return error("Invalid record");
@ -1601,6 +1658,8 @@ std::error_code BitcodeReader::parseValueSymbolTable() {
case BitstreamEntry::Error:
return error("Malformed block");
case BitstreamEntry::EndBlock:
if (Offset > 0)
Stream.JumpToBit(CurrentBit);
return std::error_code();
case BitstreamEntry::Record:
// The interesting case.
@ -1613,23 +1672,39 @@ std::error_code BitcodeReader::parseValueSymbolTable() {
default: // Default behavior: unknown type.
break;
case bitc::VST_CODE_ENTRY: { // VST_ENTRY: [valueid, namechar x N]
if (convertToString(Record, 1, ValueName))
return error("Invalid record");
unsigned ValueID = Record[0];
if (ValueID >= ValueList.size() || !ValueList[ValueID])
return error("Invalid record");
Value *V = ValueList[ValueID];
ErrorOr<Value *> ValOrErr = recordValue(Record, 1, TT);
if (std::error_code EC = ValOrErr.getError())
return EC;
ValOrErr.get();
break;
}
case bitc::VST_CODE_FNENTRY: {
// VST_FNENTRY: [valueid, offset, namechar x N]
ErrorOr<Value *> ValOrErr = recordValue(Record, 2, TT);
if (std::error_code EC = ValOrErr.getError())
return EC;
Value *V = ValOrErr.get();
V->setName(StringRef(ValueName.data(), ValueName.size()));
if (auto *GO = dyn_cast<GlobalObject>(V)) {
if (GO->getComdat() == reinterpret_cast<Comdat *>(1)) {
if (TT.isOSBinFormatMachO())
GO->setComdat(nullptr);
else
GO->setComdat(TheModule->getOrInsertComdat(V->getName()));
}
auto *GO = dyn_cast<GlobalObject>(V);
if (!GO) {
// If this is an alias, need to get the actual Function object
// it aliases, in order to set up the DeferredFunctionInfo entry below.
auto *GA = dyn_cast<GlobalAlias>(V);
if (GA)
GO = GA->getBaseObject();
assert(GO);
}
ValueName.clear();
uint64_t FuncWordOffset = Record[1];
Function *F = dyn_cast<Function>(GO);
assert(F);
uint64_t FuncBitOffset = FuncWordOffset * 32;
DeferredFunctionInfo[F] = FuncBitOffset + FuncBitcodeOffsetDelta;
// Set the NextUnreadBit to point to the last function block.
// Later when parsing is resumed after function materialization,
// we can simply skip that last function block.
if (FuncBitOffset > NextUnreadBit)
NextUnreadBit = FuncBitOffset;
break;
}
case bitc::VST_CODE_BBENTRY: {
@ -2852,9 +2927,23 @@ std::error_code BitcodeReader::parseModule(bool Resume,
return EC;
break;
case bitc::VALUE_SYMTAB_BLOCK_ID:
if (std::error_code EC = parseValueSymbolTable())
return EC;
SeenValueSymbolTable = true;
if (!SeenValueSymbolTable) {
// Either this is an old form VST without function index and an
// associated VST forward declaration record (which would have caused
// the VST to be jumped to and parsed before it was encountered
// normally in the stream), or there were no function blocks to
// trigger an earlier parsing of the VST.
assert(VSTOffset == 0 || FunctionsWithBodies.empty());
if (std::error_code EC = parseValueSymbolTable())
return EC;
SeenValueSymbolTable = true;
} else {
// We must have had a VST forward declaration record, which caused
// the parser to jump to and parse the VST earlier.
assert(VSTOffset > 0);
if (Stream.SkipBlock())
return error("Invalid record");
}
break;
case bitc::CONSTANTS_BLOCK_ID:
if (std::error_code EC = parseConstants())
@ -2882,6 +2971,32 @@ std::error_code BitcodeReader::parseModule(bool Resume,
SeenFirstFunctionBody = true;
}
if (VSTOffset > 0) {
// If we have a VST forward declaration record, make sure we
// parse the VST now if we haven't already. It is needed to
// set up the DeferredFunctionInfo vector for lazy reading.
if (!SeenValueSymbolTable) {
if (std::error_code EC =
BitcodeReader::parseValueSymbolTable(VSTOffset))
return EC;
SeenValueSymbolTable = true;
return std::error_code();
} else {
// If we have a VST forward declaration record, but have already
// parsed the VST (just above, when the first function body was
// encountered here), then we are resuming the parse after
// materializing functions. The NextUnreadBit points to the start
// of the last function block recorded in the VST (set when
// parsing the VST function entries). Skip it.
if (Stream.SkipBlock())
return error("Invalid record");
continue;
}
}
// Support older bitcode files that did not have the function
// index in the VST, nor a VST forward declaration record.
// Build the DeferredFunctionInfo vector on the fly.
if (std::error_code EC = rememberAndSkipFunctionBody())
return EC;
// Suspend parsing when we reach the function bodies. Subsequent
@ -3185,6 +3300,12 @@ std::error_code BitcodeReader::parseModule(bool Resume,
return error("Invalid record");
ValueList.shrinkTo(Record[0]);
break;
/// MODULE_CODE_VSTOFFSET: [offset]
case bitc::MODULE_CODE_VSTOFFSET:
if (Record.size() < 1)
return error("Invalid record");
VSTOffset = Record[0];
break;
}
Record.clear();
}
@ -4642,6 +4763,11 @@ std::error_code BitcodeReader::findFunctionInStream(
Function *F,
DenseMap<Function *, uint64_t>::iterator DeferredFunctionInfoIterator) {
while (DeferredFunctionInfoIterator->second == 0) {
// This is the fallback handling for the old format bitcode that
// didn't contain the function index in the VST. Assert if we end up
// here for the new format (which is the only time the VSTOffset would
// be non-zero).
assert(VSTOffset == 0);
if (Stream.AtEndOfStream())
return error("Could not find function in stream");
// ParseModule will parse the next body in the stream and set its

171
lib/Bitcode/Writer/BitcodeWriter.cpp
View File

@ -574,10 +574,40 @@ static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
}
}
// Emit top-level description of module, including target triple, inline asm,
// descriptors for global variables, and function prototype info.
static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
BitstreamWriter &Stream) {
/// Write a record that will eventually hold the word offset of the
/// module-level VST. For now the offset is 0, which will be backpatched
/// after the real VST is written. Returns the bit offset to backpatch.
static uint64_t WriteValueSymbolTableForwardDecl(const ValueSymbolTable &VST,
BitstreamWriter &Stream) {
if (VST.empty()) return 0;
// Write a placeholder value in for the offset of the real VST,
// which is written after the function blocks so that it can include
// the offset of each function. The placeholder offset will be
// updated when the real VST is written.
BitCodeAbbrev *Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
// Blocks are 32-bit aligned, so we can use a 32-bit word offset to
// hold the real VST offset. Must use fixed instead of VBR as we don't
// know how many VBR chunks to reserve ahead of time.
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(Abbv);
// Emit the placeholder
ArrayRef<unsigned> Vals = {llvm::bitc::MODULE_CODE_VSTOFFSET, 0};
Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
// Compute and return the bit offset to the placeholder, which will be
// patched when the real VST is written. We can simply subtract the 32-bit
// fixed size from the current bit number to get the location to backpatch.
return Stream.GetCurrentBitNo() - 32;
}
/// Emit top-level description of module, including target triple, inline asm,
/// descriptors for global variables, and function prototype info.
/// Returns the bit offset to backpatch with the location of the real VST.
static uint64_t WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
BitstreamWriter &Stream) {
// Emit various pieces of data attached to a module.
if (!M->getTargetTriple().empty())
WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
@ -737,6 +767,10 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
Vals.clear();
}
uint64_t VSTOffsetPlaceholder =
WriteValueSymbolTableForwardDecl(M->getValueSymbolTable(), Stream);
return VSTOffsetPlaceholder;
}
static uint64_t GetOptimizationFlags(const Value *V) {
@ -2091,32 +2125,119 @@ static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
return SE_Fixed7;
}
// Emit names for globals/functions etc.
static void WriteValueSymbolTable(const ValueSymbolTable &VST,
const ValueEnumerator &VE,
BitstreamWriter &Stream) {
if (VST.empty()) return;
/// Emit names for globals/functions etc. The VSTOffsetPlaceholder,
/// BitcodeStartBit and FunctionIndex are only passed for the module-level
/// VST, where we are including a function bitcode index and need to
/// backpatch the VST forward declaration record.
static void WriteValueSymbolTable(
const ValueSymbolTable &VST, const ValueEnumerator &VE,
BitstreamWriter &Stream, uint64_t VSTOffsetPlaceholder = 0,
uint64_t BitcodeStartBit = 0,
DenseMap<const Function *, uint64_t> *FunctionIndex = nullptr) {
if (VST.empty()) {
// WriteValueSymbolTableForwardDecl should have returned early as
// well. Ensure this handling remains in sync by asserting that
// the placeholder offset is not set.
assert(VSTOffsetPlaceholder == 0);
return;
}
if (VSTOffsetPlaceholder > 0) {
// Get the offset of the VST we are writing, and backpatch it into
// the VST forward declaration record.
uint64_t VSTOffset = Stream.GetCurrentBitNo();
// The BitcodeStartBit was the stream offset of the actual bitcode
// (e.g. excluding any initial darwin header).
VSTOffset -= BitcodeStartBit;
assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
}
Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
// For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
// records, which are not used in the per-function VSTs.
unsigned FnEntry8BitAbbrev;
unsigned FnEntry7BitAbbrev;
unsigned FnEntry6BitAbbrev;
if (VSTOffsetPlaceholder > 0) {
// 8-bit fixed-width VST_FNENTRY function strings.
BitCodeAbbrev *Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
// 7-bit fixed width VST_FNENTRY function strings.
Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
// 6-bit char6 VST_FNENTRY function strings.
Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
}
// FIXME: Set up the abbrev, we know how many values there are!
// FIXME: We know if the type names can use 7-bit ascii.
SmallVector<unsigned, 64> NameVals;
for (const ValueName &Name : VST) {
// Figure out the encoding to use for the name.
StringEncoding Bits =
getStringEncoding(Name.getKeyData(), Name.getKeyLength());
unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
NameVals.push_back(VE.getValueID(Name.getValue()));
Function *F = dyn_cast<Function>(Name.getValue());
if (!F) {
// If value is an alias, need to get the aliased base object to
// see if it is a function.
auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
if (GA && GA->getBaseObject())
F = dyn_cast<Function>(GA->getBaseObject());
}
// VST_ENTRY: [valueid, namechar x N]
// VST_FNENTRY: [valueid, funcoffset, namechar x N]
// VST_BBENTRY: [bbid, namechar x N]
unsigned Code;
if (isa<BasicBlock>(Name.getValue())) {
Code = bitc::VST_CODE_BBENTRY;
if (Bits == SE_Char6)
AbbrevToUse = VST_BBENTRY_6_ABBREV;
} else if (F && !F->isDeclaration()) {
// Must be the module-level VST, where we pass in the Index and
// have a VSTOffsetPlaceholder. The function-level VST should not
// contain any Function symbols.
assert(FunctionIndex);
assert(VSTOffsetPlaceholder > 0);
// Save the word offset of the function (from the start of the
// actual bitcode written to the stream).
assert(FunctionIndex->count(F) == 1);
uint64_t BitcodeIndex = (*FunctionIndex)[F] - BitcodeStartBit;
assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
NameVals.push_back(BitcodeIndex / 32);
Code = bitc::VST_CODE_FNENTRY;
AbbrevToUse = FnEntry8BitAbbrev;
if (Bits == SE_Char6)
AbbrevToUse = FnEntry6BitAbbrev;
else if (Bits == SE_Fixed7)
AbbrevToUse = FnEntry7BitAbbrev;
} else {
Code = bitc::VST_CODE_ENTRY;
if (Bits == SE_Char6)
@ -2125,7 +2246,6 @@ static void WriteValueSymbolTable(const ValueSymbolTable &VST,
AbbrevToUse = VST_ENTRY_7_ABBREV;
}
NameVals.push_back(VE.getValueID(Name.getValue()));
for (const char *P = Name.getKeyData(),
*E = Name.getKeyData()+Name.getKeyLength(); P != E; ++P)
NameVals.push_back((unsigned char)*P);
@ -2173,7 +2293,13 @@ static void WriteUseListBlock(const Function *F, ValueEnumerator &VE,
/// WriteFunction - Emit a function body to the module stream.
static void WriteFunction(const Function &F, ValueEnumerator &VE,
BitstreamWriter &Stream) {
BitstreamWriter &Stream,
DenseMap<const Function *, uint64_t> &FunctionIndex) {
// Save the bitcode index of the start of this function block for recording
// in the VST.
uint64_t BitcodeIndex = Stream.GetCurrentBitNo();
FunctionIndex[&F] = BitcodeIndex;
Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
VE.incorporateFunction(F);
@ -2421,7 +2547,8 @@ static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
/// WriteModule - Emit the specified module to the bitstream.
static void WriteModule(const Module *M, BitstreamWriter &Stream,
bool ShouldPreserveUseListOrder) {
bool ShouldPreserveUseListOrder,
uint64_t BitcodeStartBit) {
Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
SmallVector<unsigned, 1> Vals;
@ -2448,7 +2575,7 @@ static void WriteModule(const Module *M, BitstreamWriter &Stream,
// Emit top-level description of module, including target triple, inline asm,
// descriptors for global variables, and function prototype info.
WriteModuleInfo(M, VE, Stream);
uint64_t VSTOffsetPlaceholder = WriteModuleInfo(M, VE, Stream);
// Emit constants.
WriteModuleConstants(VE, Stream);
@ -2459,17 +2586,18 @@ static void WriteModule(const Module *M, BitstreamWriter &Stream,
// Emit metadata.
WriteModuleMetadataStore(M, Stream);
// Emit names for globals/functions etc.
WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
// Emit module-level use-lists.
if (VE.shouldPreserveUseListOrder())
WriteUseListBlock(nullptr, VE, Stream);
// Emit function bodies.
DenseMap<const Function *, uint64_t> FunctionIndex;
for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
if (!F->isDeclaration())
WriteFunction(*F, VE, Stream);
WriteFunction(*F, VE, Stream, FunctionIndex);
WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream,
VSTOffsetPlaceholder, BitcodeStartBit, &FunctionIndex);
Stream.ExitBlock();
}
@ -2560,6 +2688,11 @@ void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
// Emit the module into the buffer.
{
BitstreamWriter Stream(Buffer);
// Save the start bit of the actual bitcode, in case there is space
// saved at the start for the darwin header above. The reader stream
// will start at the bitcode, and we need the offset of the VST
// to line up.
uint64_t BitcodeStartBit = Stream.GetCurrentBitNo();
// Emit the file header.
Stream.Emit((unsigned)'B', 8);
@ -2570,7 +2703,7 @@ void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
Stream.Emit(0xD, 4);
// Emit the module.
WriteModule(M, Stream, ShouldPreserveUseListOrder);
WriteModule(M, Stream, ShouldPreserveUseListOrder, BitcodeStartBit);
}
if (TT.isOSDarwin())

29
test/Bitcode/vst-forward-declaration.ll Normal file
View File

@ -0,0 +1,29 @@
; RUN: llvm-as < %s | llvm-bcanalyzer -dump | FileCheck %s -check-prefix=BC
; Check for VST forward declaration record and VST function index records.
; BC: <VSTOFFSET
; BC: <FNENTRY
; BC: <FNENTRY
; RUN: llvm-as < %s | llvm-dis | FileCheck %s
; Check that this round-trips correctly.
; ModuleID = '<stdin>'
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; CHECK: define i32 @foo()
; Function Attrs: nounwind uwtable
define i32 @foo() #0 {
entry:
ret i32 1
}
; CHECK: define i32 @bar(i32 %x)
; Function Attrs: nounwind uwtable
define i32 @bar(i32 %x) #0 {
entry:
ret i32 %x
}

2
tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
View File

@ -165,6 +165,7 @@ static const char *GetCodeName(unsigned CodeID, unsigned BlockID,
STRINGIFY_CODE(MODULE_CODE, ALIAS)
STRINGIFY_CODE(MODULE_CODE, PURGEVALS)
STRINGIFY_CODE(MODULE_CODE, GCNAME)
STRINGIFY_CODE(MODULE_CODE, VSTOFFSET)
}
case bitc::PARAMATTR_BLOCK_ID:
switch (CodeID) {
@ -266,6 +267,7 @@ static const char *GetCodeName(unsigned CodeID, unsigned BlockID,
default: return nullptr;
STRINGIFY_CODE(VST_CODE, ENTRY)
STRINGIFY_CODE(VST_CODE, BBENTRY)
STRINGIFY_CODE(VST_CODE, FNENTRY)
}
case bitc::METADATA_ATTACHMENT_ID:
switch(CodeID) {