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llvm-project/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

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//===-- llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp --*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains support for writing Microsoft CodeView debug info.
//
//===----------------------------------------------------------------------===//
#include "CodeViewDebug.h"
#include "llvm/DebugInfo/CodeView/CodeView.h"
#include "llvm/DebugInfo/CodeView/FieldListRecordBuilder.h"
#include "llvm/DebugInfo/CodeView/Line.h"
#include "llvm/DebugInfo/CodeView/SymbolRecord.h"
#include "llvm/DebugInfo/CodeView/TypeDumper.h"
#include "llvm/DebugInfo/CodeView/TypeIndex.h"
#include "llvm/DebugInfo/CodeView/TypeRecord.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/COFF.h"
#include "llvm/Support/ScopedPrinter.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetFrameLowering.h"
using namespace llvm;
using namespace llvm::codeview;
CodeViewDebug::CodeViewDebug(AsmPrinter *AP)
: DebugHandlerBase(AP), OS(*Asm->OutStreamer), CurFn(nullptr) {
// If module doesn't have named metadata anchors or COFF debug section
// is not available, skip any debug info related stuff.
if (!MMI->getModule()->getNamedMetadata("llvm.dbg.cu") ||
!AP->getObjFileLowering().getCOFFDebugSymbolsSection()) {
Asm = nullptr;
return;
}
// Tell MMI that we have debug info.
MMI->setDebugInfoAvailability(true);
}
StringRef CodeViewDebug::getFullFilepath(const DIFile *File) {
std::string &Filepath = FileToFilepathMap[File];
if (!Filepath.empty())
return Filepath;
StringRef Dir = File->getDirectory(), Filename = File->getFilename();
// Clang emits directory and relative filename info into the IR, but CodeView
// operates on full paths. We could change Clang to emit full paths too, but
// that would increase the IR size and probably not needed for other users.
// For now, just concatenate and canonicalize the path here.
if (Filename.find(':') == 1)
Filepath = Filename;
else
Filepath = (Dir + "\\" + Filename).str();
// Canonicalize the path. We have to do it textually because we may no longer
// have access the file in the filesystem.
// First, replace all slashes with backslashes.
std::replace(Filepath.begin(), Filepath.end(), '/', '\\');
// Remove all "\.\" with "\".
size_t Cursor = 0;
while ((Cursor = Filepath.find("\\.\\", Cursor)) != std::string::npos)
Filepath.erase(Cursor, 2);
// Replace all "\XXX\..\" with "\". Don't try too hard though as the original
// path should be well-formatted, e.g. start with a drive letter, etc.
Cursor = 0;
while ((Cursor = Filepath.find("\\..\\", Cursor)) != std::string::npos) {
// Something's wrong if the path starts with "\..\", abort.
if (Cursor == 0)
break;
size_t PrevSlash = Filepath.rfind('\\', Cursor - 1);
if (PrevSlash == std::string::npos)
// Something's wrong, abort.
break;
Filepath.erase(PrevSlash, Cursor + 3 - PrevSlash);
// The next ".." might be following the one we've just erased.
Cursor = PrevSlash;
}
// Remove all duplicate backslashes.
Cursor = 0;
while ((Cursor = Filepath.find("\\\\", Cursor)) != std::string::npos)
Filepath.erase(Cursor, 1);
return Filepath;
}
unsigned CodeViewDebug::maybeRecordFile(const DIFile *F) {
unsigned NextId = FileIdMap.size() + 1;
auto Insertion = FileIdMap.insert(std::make_pair(F, NextId));
if (Insertion.second) {
// We have to compute the full filepath and emit a .cv_file directive.
StringRef FullPath = getFullFilepath(F);
NextId = OS.EmitCVFileDirective(NextId, FullPath);
assert(NextId == FileIdMap.size() && ".cv_file directive failed");
}
return Insertion.first->second;
}
CodeViewDebug::InlineSite &
CodeViewDebug::getInlineSite(const DILocation *InlinedAt,
const DISubprogram *Inlinee) {
auto SiteInsertion = CurFn->InlineSites.insert({InlinedAt, InlineSite()});
InlineSite *Site = &SiteInsertion.first->second;
if (SiteInsertion.second) {
Site->SiteFuncId = NextFuncId++;
Site->Inlinee = Inlinee;
InlinedSubprograms.insert(Inlinee);
getFuncIdForSubprogram(Inlinee);
}
return *Site;
}
TypeIndex CodeViewDebug::getFuncIdForSubprogram(const DISubprogram *SP) {
// It's possible to ask for the FuncId of a function which doesn't have a
// subprogram: inlining a function with debug info into a function with none.
if (!SP)
return TypeIndex::None();
// Check if we've already translated this subprogram.
auto I = TypeIndices.find(SP);
if (I != TypeIndices.end())
return I->second;
TypeIndex ParentScope = TypeIndex(0);
StringRef DisplayName = SP->getDisplayName();
FuncIdRecord FuncId(ParentScope, getTypeIndex(SP->getType()), DisplayName);
TypeIndex TI = TypeTable.writeFuncId(FuncId);
recordTypeIndexForDINode(SP, TI);
return TI;
}
void CodeViewDebug::recordTypeIndexForDINode(const DINode *Node, TypeIndex TI) {
auto InsertResult = TypeIndices.insert({Node, TI});
(void)InsertResult;
assert(InsertResult.second && "DINode was already assigned a type index");
}
void CodeViewDebug::recordLocalVariable(LocalVariable &&Var,
const DILocation *InlinedAt) {
if (InlinedAt) {
// This variable was inlined. Associate it with the InlineSite.
const DISubprogram *Inlinee = Var.DIVar->getScope()->getSubprogram();
InlineSite &Site = getInlineSite(InlinedAt, Inlinee);
Site.InlinedLocals.emplace_back(Var);
} else {
// This variable goes in the main ProcSym.
CurFn->Locals.emplace_back(Var);
}
}
static void addLocIfNotPresent(SmallVectorImpl<const DILocation *> &Locs,
const DILocation *Loc) {
auto B = Locs.begin(), E = Locs.end();
if (std::find(B, E, Loc) == E)
Locs.push_back(Loc);
}
void CodeViewDebug::maybeRecordLocation(DebugLoc DL,
const MachineFunction *MF) {
// Skip this instruction if it has the same location as the previous one.
if (DL == CurFn->LastLoc)
return;
const DIScope *Scope = DL.get()->getScope();
if (!Scope)
return;
// Skip this line if it is longer than the maximum we can record.
LineInfo LI(DL.getLine(), DL.getLine(), /*IsStatement=*/true);
if (LI.getStartLine() != DL.getLine() || LI.isAlwaysStepInto() ||
LI.isNeverStepInto())
return;
ColumnInfo CI(DL.getCol(), /*EndColumn=*/0);
if (CI.getStartColumn() != DL.getCol())
return;
if (!CurFn->HaveLineInfo)
CurFn->HaveLineInfo = true;
unsigned FileId = 0;
if (CurFn->LastLoc.get() && CurFn->LastLoc->getFile() == DL->getFile())
FileId = CurFn->LastFileId;
else
FileId = CurFn->LastFileId = maybeRecordFile(DL->getFile());
CurFn->LastLoc = DL;
unsigned FuncId = CurFn->FuncId;
if (const DILocation *SiteLoc = DL->getInlinedAt()) {
const DILocation *Loc = DL.get();
// If this location was actually inlined from somewhere else, give it the ID
// of the inline call site.
FuncId =
getInlineSite(SiteLoc, Loc->getScope()->getSubprogram()).SiteFuncId;
// Ensure we have links in the tree of inline call sites.
bool FirstLoc = true;
while ((SiteLoc = Loc->getInlinedAt())) {
InlineSite &Site =
getInlineSite(SiteLoc, Loc->getScope()->getSubprogram());
if (!FirstLoc)
addLocIfNotPresent(Site.ChildSites, Loc);
FirstLoc = false;
Loc = SiteLoc;
}
addLocIfNotPresent(CurFn->ChildSites, Loc);
}
OS.EmitCVLocDirective(FuncId, FileId, DL.getLine(), DL.getCol(),
/*PrologueEnd=*/false,
/*IsStmt=*/false, DL->getFilename());
}
void CodeViewDebug::emitCodeViewMagicVersion() {
OS.EmitValueToAlignment(4);
OS.AddComment("Debug section magic");
OS.EmitIntValue(COFF::DEBUG_SECTION_MAGIC, 4);
}
void CodeViewDebug::endModule() {
if (!Asm || !MMI->hasDebugInfo())
return;
assert(Asm != nullptr);
// The COFF .debug$S section consists of several subsections, each starting
// with a 4-byte control code (e.g. 0xF1, 0xF2, etc) and then a 4-byte length
// of the payload followed by the payload itself. The subsections are 4-byte
// aligned.
// Use the generic .debug$S section, and make a subsection for all the inlined
// subprograms.
switchToDebugSectionForSymbol(nullptr);
emitInlineeLinesSubsection();
// Emit per-function debug information.
for (auto &P : FnDebugInfo)
emitDebugInfoForFunction(P.first, P.second);
// Emit global variable debug information.
emitDebugInfoForGlobals();
// Switch back to the generic .debug$S section after potentially processing
// comdat symbol sections.
switchToDebugSectionForSymbol(nullptr);
// This subsection holds a file index to offset in string table table.
OS.AddComment("File index to string table offset subsection");
OS.EmitCVFileChecksumsDirective();
// This subsection holds the string table.
OS.AddComment("String table");
OS.EmitCVStringTableDirective();
// Emit type information last, so that any types we translate while emitting
// function info are included.
emitTypeInformation();
clear();
}
static void emitNullTerminatedSymbolName(MCStreamer &OS, StringRef S) {
// Microsoft's linker seems to have trouble with symbol names longer than
// 0xffd8 bytes.
S = S.substr(0, 0xffd8);
SmallString<32> NullTerminatedString(S);
NullTerminatedString.push_back('\0');
OS.EmitBytes(NullTerminatedString);
}
void CodeViewDebug::emitTypeInformation() {
// Do nothing if we have no debug info or if no non-trivial types were emitted
// to TypeTable during codegen.
NamedMDNode *CU_Nodes =
MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
if (!CU_Nodes)
return;
if (TypeTable.empty())
return;
// Start the .debug$T section with 0x4.
OS.SwitchSection(Asm->getObjFileLowering().getCOFFDebugTypesSection());
emitCodeViewMagicVersion();
SmallString<8> CommentPrefix;
if (OS.isVerboseAsm()) {
CommentPrefix += '\t';
CommentPrefix += Asm->MAI->getCommentString();
CommentPrefix += ' ';
}
CVTypeDumper CVTD(nullptr, /*PrintRecordBytes=*/false);
TypeTable.ForEachRecord(
[&](TypeIndex Index, StringRef Record) {
if (OS.isVerboseAsm()) {
// Emit a block comment describing the type record for readability.
SmallString<512> CommentBlock;
raw_svector_ostream CommentOS(CommentBlock);
ScopedPrinter SP(CommentOS);
SP.setPrefix(CommentPrefix);
CVTD.setPrinter(&SP);
bool DumpSuccess =
CVTD.dump({Record.bytes_begin(), Record.bytes_end()});
(void)DumpSuccess;
assert(DumpSuccess && "produced malformed type record");
// emitRawComment will insert its own tab and comment string before
// the first line, so strip off our first one. It also prints its own
// newline.
OS.emitRawComment(
CommentOS.str().drop_front(CommentPrefix.size() - 1).rtrim());
}
OS.EmitBinaryData(Record);
});
}
void CodeViewDebug::emitInlineeLinesSubsection() {
if (InlinedSubprograms.empty())
return;
OS.AddComment("Inlinee lines subsection");
MCSymbol *InlineEnd = beginCVSubsection(ModuleSubstreamKind::InlineeLines);
// We don't provide any extra file info.
// FIXME: Find out if debuggers use this info.
OS.AddComment("Inlinee lines signature");
OS.EmitIntValue(unsigned(InlineeLinesSignature::Normal), 4);
for (const DISubprogram *SP : InlinedSubprograms) {
assert(TypeIndices.count(SP));
TypeIndex InlineeIdx = TypeIndices[SP];
OS.AddBlankLine();
unsigned FileId = maybeRecordFile(SP->getFile());
OS.AddComment("Inlined function " + SP->getDisplayName() + " starts at " +
SP->getFilename() + Twine(':') + Twine(SP->getLine()));
OS.AddBlankLine();
// The filechecksum table uses 8 byte entries for now, and file ids start at
// 1.
unsigned FileOffset = (FileId - 1) * 8;
OS.AddComment("Type index of inlined function");
OS.EmitIntValue(InlineeIdx.getIndex(), 4);
OS.AddComment("Offset into filechecksum table");
OS.EmitIntValue(FileOffset, 4);
OS.AddComment("Starting line number");
OS.EmitIntValue(SP->getLine(), 4);
}
endCVSubsection(InlineEnd);
}
void CodeViewDebug::collectInlineSiteChildren(
SmallVectorImpl<unsigned> &Children, const FunctionInfo &FI,
const InlineSite &Site) {
for (const DILocation *ChildSiteLoc : Site.ChildSites) {
auto I = FI.InlineSites.find(ChildSiteLoc);
const InlineSite &ChildSite = I->second;
Children.push_back(ChildSite.SiteFuncId);
collectInlineSiteChildren(Children, FI, ChildSite);
}
}
void CodeViewDebug::emitInlinedCallSite(const FunctionInfo &FI,
const DILocation *InlinedAt,
const InlineSite &Site) {
MCSymbol *InlineBegin = MMI->getContext().createTempSymbol(),
*InlineEnd = MMI->getContext().createTempSymbol();
assert(TypeIndices.count(Site.Inlinee));
TypeIndex InlineeIdx = TypeIndices[Site.Inlinee];
// SymbolRecord
OS.AddComment("Record length");
OS.emitAbsoluteSymbolDiff(InlineEnd, InlineBegin, 2); // RecordLength
OS.EmitLabel(InlineBegin);
OS.AddComment("Record kind: S_INLINESITE");
OS.EmitIntValue(SymbolKind::S_INLINESITE, 2); // RecordKind
OS.AddComment("PtrParent");
OS.EmitIntValue(0, 4);
OS.AddComment("PtrEnd");
OS.EmitIntValue(0, 4);
OS.AddComment("Inlinee type index");
OS.EmitIntValue(InlineeIdx.getIndex(), 4);
unsigned FileId = maybeRecordFile(Site.Inlinee->getFile());
unsigned StartLineNum = Site.Inlinee->getLine();
SmallVector<unsigned, 3> SecondaryFuncIds;
collectInlineSiteChildren(SecondaryFuncIds, FI, Site);
OS.EmitCVInlineLinetableDirective(Site.SiteFuncId, FileId, StartLineNum,
FI.Begin, FI.End, SecondaryFuncIds);
OS.EmitLabel(InlineEnd);
for (const LocalVariable &Var : Site.InlinedLocals)
emitLocalVariable(Var);
// Recurse on child inlined call sites before closing the scope.
for (const DILocation *ChildSite : Site.ChildSites) {
auto I = FI.InlineSites.find(ChildSite);
assert(I != FI.InlineSites.end() &&
"child site not in function inline site map");
emitInlinedCallSite(FI, ChildSite, I->second);
}
// Close the scope.
OS.AddComment("Record length");
OS.EmitIntValue(2, 2); // RecordLength
OS.AddComment("Record kind: S_INLINESITE_END");
OS.EmitIntValue(SymbolKind::S_INLINESITE_END, 2); // RecordKind
}
void CodeViewDebug::switchToDebugSectionForSymbol(const MCSymbol *GVSym) {
// If we have a symbol, it may be in a section that is COMDAT. If so, find the
// comdat key. A section may be comdat because of -ffunction-sections or
// because it is comdat in the IR.
MCSectionCOFF *GVSec =
GVSym ? dyn_cast<MCSectionCOFF>(&GVSym->getSection()) : nullptr;
const MCSymbol *KeySym = GVSec ? GVSec->getCOMDATSymbol() : nullptr;
MCSectionCOFF *DebugSec = cast<MCSectionCOFF>(
Asm->getObjFileLowering().getCOFFDebugSymbolsSection());
DebugSec = OS.getContext().getAssociativeCOFFSection(DebugSec, KeySym);
OS.SwitchSection(DebugSec);
// Emit the magic version number if this is the first time we've switched to
// this section.
if (ComdatDebugSections.insert(DebugSec).second)
emitCodeViewMagicVersion();
}
void CodeViewDebug::emitDebugInfoForFunction(const Function *GV,
FunctionInfo &FI) {
// For each function there is a separate subsection
// which holds the PC to file:line table.
const MCSymbol *Fn = Asm->getSymbol(GV);
assert(Fn);
// Switch to the to a comdat section, if appropriate.
switchToDebugSectionForSymbol(Fn);
StringRef FuncName;
if (auto *SP = GV->getSubprogram())
FuncName = SP->getDisplayName();
// If our DISubprogram name is empty, use the mangled name.
if (FuncName.empty())
FuncName = GlobalValue::getRealLinkageName(GV->getName());
// Emit a symbol subsection, required by VS2012+ to find function boundaries.
OS.AddComment("Symbol subsection for " + Twine(FuncName));
MCSymbol *SymbolsEnd = beginCVSubsection(ModuleSubstreamKind::Symbols);
{
MCSymbol *ProcRecordBegin = MMI->getContext().createTempSymbol(),
*ProcRecordEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Record length");
OS.emitAbsoluteSymbolDiff(ProcRecordEnd, ProcRecordBegin, 2);
OS.EmitLabel(ProcRecordBegin);
OS.AddComment("Record kind: S_GPROC32_ID");
OS.EmitIntValue(unsigned(SymbolKind::S_GPROC32_ID), 2);
// These fields are filled in by tools like CVPACK which run after the fact.
OS.AddComment("PtrParent");
OS.EmitIntValue(0, 4);
OS.AddComment("PtrEnd");
OS.EmitIntValue(0, 4);
OS.AddComment("PtrNext");
OS.EmitIntValue(0, 4);
// This is the important bit that tells the debugger where the function
// code is located and what's its size:
OS.AddComment("Code size");
OS.emitAbsoluteSymbolDiff(FI.End, Fn, 4);
OS.AddComment("Offset after prologue");
OS.EmitIntValue(0, 4);
OS.AddComment("Offset before epilogue");
OS.EmitIntValue(0, 4);
OS.AddComment("Function type index");
OS.EmitIntValue(getFuncIdForSubprogram(GV->getSubprogram()).getIndex(), 4);
OS.AddComment("Function section relative address");
OS.EmitCOFFSecRel32(Fn);
OS.AddComment("Function section index");
OS.EmitCOFFSectionIndex(Fn);
OS.AddComment("Flags");
OS.EmitIntValue(0, 1);
// Emit the function display name as a null-terminated string.
OS.AddComment("Function name");
// Truncate the name so we won't overflow the record length field.
emitNullTerminatedSymbolName(OS, FuncName);
OS.EmitLabel(ProcRecordEnd);
for (const LocalVariable &Var : FI.Locals)
emitLocalVariable(Var);
// Emit inlined call site information. Only emit functions inlined directly
// into the parent function. We'll emit the other sites recursively as part
// of their parent inline site.
for (const DILocation *InlinedAt : FI.ChildSites) {
auto I = FI.InlineSites.find(InlinedAt);
assert(I != FI.InlineSites.end() &&
"child site not in function inline site map");
emitInlinedCallSite(FI, InlinedAt, I->second);
}
// We're done with this function.
OS.AddComment("Record length");
OS.EmitIntValue(0x0002, 2);
OS.AddComment("Record kind: S_PROC_ID_END");
OS.EmitIntValue(unsigned(SymbolKind::S_PROC_ID_END), 2);
}
endCVSubsection(SymbolsEnd);
// We have an assembler directive that takes care of the whole line table.
OS.EmitCVLinetableDirective(FI.FuncId, Fn, FI.End);
}
CodeViewDebug::LocalVarDefRange
CodeViewDebug::createDefRangeMem(uint16_t CVRegister, int Offset) {
LocalVarDefRange DR;
DR.InMemory = -1;
DR.DataOffset = Offset;
assert(DR.DataOffset == Offset && "truncation");
DR.StructOffset = 0;
DR.CVRegister = CVRegister;
return DR;
}
CodeViewDebug::LocalVarDefRange
CodeViewDebug::createDefRangeReg(uint16_t CVRegister) {
LocalVarDefRange DR;
DR.InMemory = 0;
DR.DataOffset = 0;
DR.StructOffset = 0;
DR.CVRegister = CVRegister;
return DR;
}
void CodeViewDebug::collectVariableInfoFromMMITable(
DenseSet<InlinedVariable> &Processed) {
const TargetSubtargetInfo &TSI = Asm->MF->getSubtarget();
const TargetFrameLowering *TFI = TSI.getFrameLowering();
const TargetRegisterInfo *TRI = TSI.getRegisterInfo();
for (const MachineModuleInfo::VariableDbgInfo &VI :
MMI->getVariableDbgInfo()) {
if (!VI.Var)
continue;
assert(VI.Var->isValidLocationForIntrinsic(VI.Loc) &&
"Expected inlined-at fields to agree");
Processed.insert(InlinedVariable(VI.Var, VI.Loc->getInlinedAt()));
LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
// If variable scope is not found then skip this variable.
if (!Scope)
continue;
// Get the frame register used and the offset.
unsigned FrameReg = 0;
int FrameOffset = TFI->getFrameIndexReference(*Asm->MF, VI.Slot, FrameReg);
uint16_t CVReg = TRI->getCodeViewRegNum(FrameReg);
// Calculate the label ranges.
LocalVarDefRange DefRange = createDefRangeMem(CVReg, FrameOffset);
for (const InsnRange &Range : Scope->getRanges()) {
const MCSymbol *Begin = getLabelBeforeInsn(Range.first);
const MCSymbol *End = getLabelAfterInsn(Range.second);
End = End ? End : Asm->getFunctionEnd();
DefRange.Ranges.emplace_back(Begin, End);
}
LocalVariable Var;
Var.DIVar = VI.Var;
Var.DefRanges.emplace_back(std::move(DefRange));
recordLocalVariable(std::move(Var), VI.Loc->getInlinedAt());
}
}
void CodeViewDebug::collectVariableInfo(const DISubprogram *SP) {
DenseSet<InlinedVariable> Processed;
// Grab the variable info that was squirreled away in the MMI side-table.
collectVariableInfoFromMMITable(Processed);
const TargetRegisterInfo *TRI = Asm->MF->getSubtarget().getRegisterInfo();
for (const auto &I : DbgValues) {
InlinedVariable IV = I.first;
if (Processed.count(IV))
continue;
const DILocalVariable *DIVar = IV.first;
const DILocation *InlinedAt = IV.second;
// Instruction ranges, specifying where IV is accessible.
const auto &Ranges = I.second;
LexicalScope *Scope = nullptr;
if (InlinedAt)
Scope = LScopes.findInlinedScope(DIVar->getScope(), InlinedAt);
else
Scope = LScopes.findLexicalScope(DIVar->getScope());
// If variable scope is not found then skip this variable.
if (!Scope)
continue;
LocalVariable Var;
Var.DIVar = DIVar;
// Calculate the definition ranges.
for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
const InsnRange &Range = *I;
const MachineInstr *DVInst = Range.first;
assert(DVInst->isDebugValue() && "Invalid History entry");
const DIExpression *DIExpr = DVInst->getDebugExpression();
// Bail if there is a complex DWARF expression for now.
if (DIExpr && DIExpr->getNumElements() > 0)
continue;
// Bail if operand 0 is not a valid register. This means the variable is a
// simple constant, or is described by a complex expression.
// FIXME: Find a way to represent constant variables, since they are
// relatively common.
unsigned Reg =
DVInst->getOperand(0).isReg() ? DVInst->getOperand(0).getReg() : 0;
if (Reg == 0)
continue;
// Handle the two cases we can handle: indirect in memory and in register.
bool IsIndirect = DVInst->getOperand(1).isImm();
unsigned CVReg = TRI->getCodeViewRegNum(DVInst->getOperand(0).getReg());
{
LocalVarDefRange DefRange;
if (IsIndirect) {
int64_t Offset = DVInst->getOperand(1).getImm();
DefRange = createDefRangeMem(CVReg, Offset);
} else {
DefRange = createDefRangeReg(CVReg);
}
if (Var.DefRanges.empty() ||
Var.DefRanges.back().isDifferentLocation(DefRange)) {
Var.DefRanges.emplace_back(std::move(DefRange));
}
}
// Compute the label range.
const MCSymbol *Begin = getLabelBeforeInsn(Range.first);
const MCSymbol *End = getLabelAfterInsn(Range.second);
if (!End) {
if (std::next(I) != E)
End = getLabelBeforeInsn(std::next(I)->first);
else
End = Asm->getFunctionEnd();
}
// If the last range end is our begin, just extend the last range.
// Otherwise make a new range.
SmallVectorImpl<std::pair<const MCSymbol *, const MCSymbol *>> &Ranges =
Var.DefRanges.back().Ranges;
if (!Ranges.empty() && Ranges.back().second == Begin)
Ranges.back().second = End;
else
Ranges.emplace_back(Begin, End);
// FIXME: Do more range combining.
}
recordLocalVariable(std::move(Var), InlinedAt);
}
}
void CodeViewDebug::beginFunction(const MachineFunction *MF) {
assert(!CurFn && "Can't process two functions at once!");
if (!Asm || !MMI->hasDebugInfo())
return;
DebugHandlerBase::beginFunction(MF);
const Function *GV = MF->getFunction();
assert(FnDebugInfo.count(GV) == false);
CurFn = &FnDebugInfo[GV];
CurFn->FuncId = NextFuncId++;
CurFn->Begin = Asm->getFunctionBegin();
// Find the end of the function prolog. First known non-DBG_VALUE and
// non-frame setup location marks the beginning of the function body.
// FIXME: is there a simpler a way to do this? Can we just search
// for the first instruction of the function, not the last of the prolog?
DebugLoc PrologEndLoc;
bool EmptyPrologue = true;
for (const auto &MBB : *MF) {
for (const auto &MI : MBB) {
if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
MI.getDebugLoc()) {
PrologEndLoc = MI.getDebugLoc();
break;
} else if (!MI.isDebugValue()) {
EmptyPrologue = false;
}
}
}
// Record beginning of function if we have a non-empty prologue.
if (PrologEndLoc && !EmptyPrologue) {
DebugLoc FnStartDL = PrologEndLoc.getFnDebugLoc();
maybeRecordLocation(FnStartDL, MF);
}
}
TypeIndex CodeViewDebug::lowerType(const DIType *Ty) {
// Generic dispatch for lowering an unknown type.
switch (Ty->getTag()) {
case dwarf::DW_TAG_typedef:
return lowerTypeAlias(cast<DIDerivedType>(Ty));
case dwarf::DW_TAG_base_type:
return lowerTypeBasic(cast<DIBasicType>(Ty));
case dwarf::DW_TAG_pointer_type:
case dwarf::DW_TAG_reference_type:
case dwarf::DW_TAG_rvalue_reference_type:
return lowerTypePointer(cast<DIDerivedType>(Ty));
case dwarf::DW_TAG_ptr_to_member_type:
return lowerTypeMemberPointer(cast<DIDerivedType>(Ty));
case dwarf::DW_TAG_const_type:
case dwarf::DW_TAG_volatile_type:
return lowerTypeModifier(cast<DIDerivedType>(Ty));
case dwarf::DW_TAG_subroutine_type:
return lowerTypeFunction(cast<DISubroutineType>(Ty));
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_structure_type:
return lowerTypeClass(cast<DICompositeType>(Ty));
case dwarf::DW_TAG_union_type:
return lowerTypeUnion(cast<DICompositeType>(Ty));
default:
// Use the null type index.
return TypeIndex();
}
}
TypeIndex CodeViewDebug::lowerTypeAlias(const DIDerivedType *Ty) {
// TODO: MSVC emits a S_UDT record.
DITypeRef UnderlyingTypeRef = Ty->getBaseType();
TypeIndex UnderlyingTypeIndex = getTypeIndex(UnderlyingTypeRef);
if (UnderlyingTypeIndex == TypeIndex(SimpleTypeKind::Int32Long) &&
Ty->getName() == "HRESULT")
return TypeIndex(SimpleTypeKind::HResult);
if (UnderlyingTypeIndex == TypeIndex(SimpleTypeKind::UInt16Short) &&
Ty->getName() == "wchar_t")
return TypeIndex(SimpleTypeKind::WideCharacter);
return UnderlyingTypeIndex;
}
TypeIndex CodeViewDebug::lowerTypeBasic(const DIBasicType *Ty) {
TypeIndex Index;
dwarf::TypeKind Kind;
uint32_t ByteSize;
Kind = static_cast<dwarf::TypeKind>(Ty->getEncoding());
ByteSize = Ty->getSizeInBits() / 8;
SimpleTypeKind STK = SimpleTypeKind::None;
switch (Kind) {
case dwarf::DW_ATE_address:
// FIXME: Translate
break;
case dwarf::DW_ATE_boolean:
switch (ByteSize) {
case 1: STK = SimpleTypeKind::Boolean8; break;
case 2: STK = SimpleTypeKind::Boolean16; break;
case 4: STK = SimpleTypeKind::Boolean32; break;
case 8: STK = SimpleTypeKind::Boolean64; break;
case 16: STK = SimpleTypeKind::Boolean128; break;
}
break;
case dwarf::DW_ATE_complex_float:
switch (ByteSize) {
case 2: STK = SimpleTypeKind::Complex16; break;
case 4: STK = SimpleTypeKind::Complex32; break;
case 8: STK = SimpleTypeKind::Complex64; break;
case 10: STK = SimpleTypeKind::Complex80; break;
case 16: STK = SimpleTypeKind::Complex128; break;
}
break;
case dwarf::DW_ATE_float:
switch (ByteSize) {
case 2: STK = SimpleTypeKind::Float16; break;
case 4: STK = SimpleTypeKind::Float32; break;
case 6: STK = SimpleTypeKind::Float48; break;
case 8: STK = SimpleTypeKind::Float64; break;
case 10: STK = SimpleTypeKind::Float80; break;
case 16: STK = SimpleTypeKind::Float128; break;
}
break;
case dwarf::DW_ATE_signed:
switch (ByteSize) {
case 1: STK = SimpleTypeKind::SByte; break;
case 2: STK = SimpleTypeKind::Int16Short; break;
case 4: STK = SimpleTypeKind::Int32; break;
case 8: STK = SimpleTypeKind::Int64Quad; break;
case 16: STK = SimpleTypeKind::Int128Oct; break;
}
break;
case dwarf::DW_ATE_unsigned:
switch (ByteSize) {
case 1: STK = SimpleTypeKind::Byte; break;
case 2: STK = SimpleTypeKind::UInt16Short; break;
case 4: STK = SimpleTypeKind::UInt32; break;
case 8: STK = SimpleTypeKind::UInt64Quad; break;
case 16: STK = SimpleTypeKind::UInt128Oct; break;
}
break;
case dwarf::DW_ATE_UTF:
switch (ByteSize) {
case 2: STK = SimpleTypeKind::Character16; break;
case 4: STK = SimpleTypeKind::Character32; break;
}
break;
case dwarf::DW_ATE_signed_char:
if (ByteSize == 1)
STK = SimpleTypeKind::SignedCharacter;
break;
case dwarf::DW_ATE_unsigned_char:
if (ByteSize == 1)
STK = SimpleTypeKind::UnsignedCharacter;
break;
default:
break;
}
// Apply some fixups based on the source-level type name.
if (STK == SimpleTypeKind::Int32 && Ty->getName() == "long int")
STK = SimpleTypeKind::Int32Long;
if (STK == SimpleTypeKind::UInt32 && Ty->getName() == "long unsigned int")
STK = SimpleTypeKind::UInt32Long;
if (STK == SimpleTypeKind::UInt16Short &&
(Ty->getName() == "wchar_t" || Ty->getName() == "__wchar_t"))
STK = SimpleTypeKind::WideCharacter;
if ((STK == SimpleTypeKind::SignedCharacter ||
STK == SimpleTypeKind::UnsignedCharacter) &&
Ty->getName() == "char")
STK = SimpleTypeKind::NarrowCharacter;
return TypeIndex(STK);
}
TypeIndex CodeViewDebug::lowerTypePointer(const DIDerivedType *Ty) {
TypeIndex PointeeTI = getTypeIndex(Ty->getBaseType());
// Pointers to simple types can use SimpleTypeMode, rather than having a
// dedicated pointer type record.
if (PointeeTI.isSimple() &&
PointeeTI.getSimpleMode() == SimpleTypeMode::Direct &&
Ty->getTag() == dwarf::DW_TAG_pointer_type) {
SimpleTypeMode Mode = Ty->getSizeInBits() == 64
? SimpleTypeMode::NearPointer64
: SimpleTypeMode::NearPointer32;
return TypeIndex(PointeeTI.getSimpleKind(), Mode);
}
PointerKind PK =
Ty->getSizeInBits() == 64 ? PointerKind::Near64 : PointerKind::Near32;
PointerMode PM = PointerMode::Pointer;
switch (Ty->getTag()) {
default: llvm_unreachable("not a pointer tag type");
case dwarf::DW_TAG_pointer_type:
PM = PointerMode::Pointer;
break;
case dwarf::DW_TAG_reference_type:
PM = PointerMode::LValueReference;
break;
case dwarf::DW_TAG_rvalue_reference_type:
PM = PointerMode::RValueReference;
break;
}
// FIXME: MSVC folds qualifiers into PointerOptions in the context of a method
// 'this' pointer, but not normal contexts. Figure out what we're supposed to
// do.
PointerOptions PO = PointerOptions::None;
PointerRecord PR(PointeeTI, PK, PM, PO, Ty->getSizeInBits() / 8);
return TypeTable.writePointer(PR);
}
TypeIndex CodeViewDebug::lowerTypeMemberPointer(const DIDerivedType *Ty) {
assert(Ty->getTag() == dwarf::DW_TAG_ptr_to_member_type);
TypeIndex ClassTI = getTypeIndex(Ty->getClassType());
TypeIndex PointeeTI = getTypeIndex(Ty->getBaseType());
PointerKind PK = Asm->MAI->getPointerSize() == 8 ? PointerKind::Near64
: PointerKind::Near32;
PointerMode PM = isa<DISubroutineType>(Ty->getBaseType())
? PointerMode::PointerToMemberFunction
: PointerMode::PointerToDataMember;
PointerOptions PO = PointerOptions::None; // FIXME
// FIXME: Thread this ABI info through metadata.
PointerToMemberRepresentation PMR = PointerToMemberRepresentation::Unknown;
MemberPointerInfo MPI(ClassTI, PMR);
PointerRecord PR(PointeeTI, PK, PM, PO, Ty->getSizeInBits() / 8, MPI);
return TypeTable.writePointer(PR);
}
TypeIndex CodeViewDebug::lowerTypeModifier(const DIDerivedType *Ty) {
ModifierOptions Mods = ModifierOptions::None;
bool IsModifier = true;
const DIType *BaseTy = Ty;
while (IsModifier && BaseTy) {
// FIXME: Need to add DWARF tag for __unaligned.
switch (BaseTy->getTag()) {
case dwarf::DW_TAG_const_type:
Mods |= ModifierOptions::Const;
break;
case dwarf::DW_TAG_volatile_type:
Mods |= ModifierOptions::Volatile;
break;
default:
IsModifier = false;
break;
}
if (IsModifier)
BaseTy = cast<DIDerivedType>(BaseTy)->getBaseType().resolve();
}
TypeIndex ModifiedTI = getTypeIndex(BaseTy);
ModifierRecord MR(ModifiedTI, Mods);
return TypeTable.writeModifier(MR);
}
TypeIndex CodeViewDebug::lowerTypeFunction(const DISubroutineType *Ty) {
SmallVector<TypeIndex, 8> ReturnAndArgTypeIndices;
for (DITypeRef ArgTypeRef : Ty->getTypeArray())
ReturnAndArgTypeIndices.push_back(getTypeIndex(ArgTypeRef));
TypeIndex ReturnTypeIndex = TypeIndex::Void();
ArrayRef<TypeIndex> ArgTypeIndices = None;
if (!ReturnAndArgTypeIndices.empty()) {
auto ReturnAndArgTypesRef = makeArrayRef(ReturnAndArgTypeIndices);
ReturnTypeIndex = ReturnAndArgTypesRef.front();
ArgTypeIndices = ReturnAndArgTypesRef.drop_front();
}
ArgListRecord ArgListRec(TypeRecordKind::ArgList, ArgTypeIndices);
TypeIndex ArgListIndex = TypeTable.writeArgList(ArgListRec);
// TODO: We should use DW_AT_calling_convention to determine what CC this
// procedure record should have.
// TODO: Some functions are member functions, we should use a more appropriate
// record for those.
ProcedureRecord Procedure(ReturnTypeIndex, CallingConvention::NearC,
FunctionOptions::None, ArgTypeIndices.size(),
ArgListIndex);
return TypeTable.writeProcedure(Procedure);
}
static MemberAccess translateAccessFlags(unsigned RecordTag,
const DIType *Member) {
switch (Member->getFlags() & DINode::FlagAccessibility) {
case DINode::FlagPrivate: return MemberAccess::Private;
case DINode::FlagPublic: return MemberAccess::Public;
case DINode::FlagProtected: return MemberAccess::Protected;
case 0:
// If there was no explicit access control, provide the default for the tag.
return RecordTag == dwarf::DW_TAG_class_type ? MemberAccess::Private
: MemberAccess::Public;
}
llvm_unreachable("access flags are exclusive");
}
static TypeRecordKind getRecordKind(const DICompositeType *Ty) {
switch (Ty->getTag()) {
case dwarf::DW_TAG_class_type: return TypeRecordKind::Class;
case dwarf::DW_TAG_structure_type: return TypeRecordKind::Struct;
}
llvm_unreachable("unexpected tag");
}
/// Return the HasUniqueName option if it should be present in ClassOptions, or
/// None otherwise.
static ClassOptions getRecordUniqueNameOption(const DICompositeType *Ty) {
// MSVC always sets this flag now, even for local types. Clang doesn't always
// appear to give every type a linkage name, which may be problematic for us.
// FIXME: Investigate the consequences of not following them here.
return !Ty->getIdentifier().empty() ? ClassOptions::HasUniqueName
: ClassOptions::None;
}
TypeIndex CodeViewDebug::lowerTypeClass(const DICompositeType *Ty) {
// First, construct the forward decl. Don't look into Ty to compute the
// forward decl options, since it might not be available in all TUs.
TypeRecordKind Kind = getRecordKind(Ty);
ClassOptions CO =
ClassOptions::ForwardReference | getRecordUniqueNameOption(Ty);
TypeIndex FwdDeclTI = TypeTable.writeClass(ClassRecord(
Kind, 0, CO, HfaKind::None, WindowsRTClassKind::None, TypeIndex(),
TypeIndex(), TypeIndex(), 0, Ty->getName(), Ty->getIdentifier()));
return FwdDeclTI;
}
TypeIndex CodeViewDebug::lowerCompleteTypeClass(const DICompositeType *Ty) {
// Construct the field list and complete type record.
TypeRecordKind Kind = getRecordKind(Ty);
// FIXME: Other ClassOptions, like ContainsNestedClass and NestedClass.
ClassOptions CO = ClassOptions::None | getRecordUniqueNameOption(Ty);
TypeIndex FTI;
unsigned FieldCount;
std::tie(FTI, FieldCount) = lowerRecordFieldList(Ty);
uint64_t SizeInBytes = Ty->getSizeInBits() / 8;
return TypeTable.writeClass(ClassRecord(Kind, FieldCount, CO, HfaKind::None,
WindowsRTClassKind::None, FTI,
TypeIndex(), TypeIndex(), SizeInBytes,
Ty->getName(), Ty->getIdentifier()));
// FIXME: Make an LF_UDT_SRC_LINE record.
}
TypeIndex CodeViewDebug::lowerTypeUnion(const DICompositeType *Ty) {
ClassOptions CO =
ClassOptions::ForwardReference | getRecordUniqueNameOption(Ty);
TypeIndex FwdDeclTI =
TypeTable.writeUnion(UnionRecord(0, CO, HfaKind::None, TypeIndex(), 0,
Ty->getName(), Ty->getIdentifier()));
return FwdDeclTI;
}
TypeIndex CodeViewDebug::lowerCompleteTypeUnion(const DICompositeType *Ty) {
ClassOptions CO = ClassOptions::None | getRecordUniqueNameOption(Ty);
TypeIndex FTI;
unsigned FieldCount;
std::tie(FTI, FieldCount) = lowerRecordFieldList(Ty);
uint64_t SizeInBytes = Ty->getSizeInBits() / 8;
return TypeTable.writeUnion(UnionRecord(FieldCount, CO, HfaKind::None, FTI,
SizeInBytes, Ty->getName(),
Ty->getIdentifier()));
// FIXME: Make an LF_UDT_SRC_LINE record.
}
std::pair<TypeIndex, unsigned>
CodeViewDebug::lowerRecordFieldList(const DICompositeType *Ty) {
// Manually count members. MSVC appears to count everything that generates a
// field list record. Each individual overload in a method overload group
// contributes to this count, even though the overload group is a single field
// list record.
unsigned MemberCount = 0;
FieldListRecordBuilder Fields;
for (const DINode *Element : Ty->getElements()) {
// We assume that the frontend provides all members in source declaration
// order, which is what MSVC does.
if (!Element)
continue;
if (auto *SP = dyn_cast<DISubprogram>(Element)) {
// C++ method.
// FIXME: Overloaded methods are grouped together, so we'll need two
// passes to group them.
(void)SP;
} else if (auto *Member = dyn_cast<DIDerivedType>(Element)) {
if (Member->getTag() == dwarf::DW_TAG_member) {
if (Member->isStaticMember()) {
// Static data member.
Fields.writeStaticDataMember(StaticDataMemberRecord(
translateAccessFlags(Ty->getTag(), Member),
getTypeIndex(Member->getBaseType()), Member->getName()));
MemberCount++;
} else {
// Data member.
// FIXME: Make a BitFieldRecord for bitfields.
Fields.writeDataMember(DataMemberRecord(
translateAccessFlags(Ty->getTag(), Member),
getTypeIndex(Member->getBaseType()),
Member->getOffsetInBits() / 8, Member->getName()));
MemberCount++;
}
} else if (Member->getTag() == dwarf::DW_TAG_friend) {
// Ignore friend members. It appears that MSVC emitted info about
// friends in the past, but modern versions do not.
}
// FIXME: Get clang to emit nested types here and do something with
// them.
}
// Skip other unrecognized kinds of elements.
}
return {TypeTable.writeFieldList(Fields), MemberCount};
}
TypeIndex CodeViewDebug::getTypeIndex(DITypeRef TypeRef) {
const DIType *Ty = TypeRef.resolve();
// The null DIType is the void type. Don't try to hash it.
if (!Ty)
return TypeIndex::Void();
// Check if we've already translated this type. Don't try to do a
// get-or-create style insertion that caches the hash lookup across the
// lowerType call. It will update the TypeIndices map.
auto I = TypeIndices.find(Ty);
if (I != TypeIndices.end())
return I->second;
TypeIndex TI = lowerType(Ty);
recordTypeIndexForDINode(Ty, TI);
return TI;
}
TypeIndex CodeViewDebug::getCompleteTypeIndex(DITypeRef TypeRef) {
const DIType *Ty = TypeRef.resolve();
// The null DIType is the void type. Don't try to hash it.
if (!Ty)
return TypeIndex::Void();
// If this is a non-record type, the complete type index is the same as the
// normal type index. Just call getTypeIndex.
switch (Ty->getTag()) {
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_structure_type:
case dwarf::DW_TAG_union_type:
break;
default:
return getTypeIndex(Ty);
}
// Check if we've already translated the complete record type. Lowering a
// complete type should never trigger lowering another complete type, so we
// can reuse the hash table lookup result.
const auto *CTy = cast<DICompositeType>(Ty);
auto InsertResult = CompleteTypeIndices.insert({CTy, TypeIndex()});
if (!InsertResult.second)
return InsertResult.first->second;
// Make sure the forward declaration is emitted first. It's unclear if this
// is necessary, but MSVC does it, and we should follow suit until we can show
// otherwise.
TypeIndex FwdDeclTI = getTypeIndex(CTy);
// Just use the forward decl if we don't have complete type info. This might
// happen if the frontend is using modules and expects the complete definition
// to be emitted elsewhere.
if (CTy->isForwardDecl())
return FwdDeclTI;
TypeIndex TI;
switch (CTy->getTag()) {
case dwarf::DW_TAG_class_type:
case dwarf::DW_TAG_structure_type:
TI = lowerCompleteTypeClass(CTy);
break;
case dwarf::DW_TAG_union_type:
TI = lowerCompleteTypeUnion(CTy);
break;
default:
llvm_unreachable("not a record");
}
InsertResult.first->second = TI;
return TI;
}
void CodeViewDebug::emitLocalVariable(const LocalVariable &Var) {
// LocalSym record, see SymbolRecord.h for more info.
MCSymbol *LocalBegin = MMI->getContext().createTempSymbol(),
*LocalEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Record length");
OS.emitAbsoluteSymbolDiff(LocalEnd, LocalBegin, 2);
OS.EmitLabel(LocalBegin);
OS.AddComment("Record kind: S_LOCAL");
OS.EmitIntValue(unsigned(SymbolKind::S_LOCAL), 2);
LocalSymFlags Flags = LocalSymFlags::None;
if (Var.DIVar->isParameter())
Flags |= LocalSymFlags::IsParameter;
if (Var.DefRanges.empty())
Flags |= LocalSymFlags::IsOptimizedOut;
OS.AddComment("TypeIndex");
TypeIndex TI = getCompleteTypeIndex(Var.DIVar->getType());
OS.EmitIntValue(TI.getIndex(), 4);
OS.AddComment("Flags");
OS.EmitIntValue(static_cast<uint16_t>(Flags), 2);
// Truncate the name so we won't overflow the record length field.
emitNullTerminatedSymbolName(OS, Var.DIVar->getName());
OS.EmitLabel(LocalEnd);
// Calculate the on disk prefix of the appropriate def range record. The
// records and on disk formats are described in SymbolRecords.h. BytePrefix
// should be big enough to hold all forms without memory allocation.
SmallString<20> BytePrefix;
for (const LocalVarDefRange &DefRange : Var.DefRanges) {
BytePrefix.clear();
// FIXME: Handle bitpieces.
if (DefRange.StructOffset != 0)
continue;
if (DefRange.InMemory) {
DefRangeRegisterRelSym Sym(DefRange.CVRegister, 0, DefRange.DataOffset, 0,
0, 0, ArrayRef<LocalVariableAddrGap>());
ulittle16_t SymKind = ulittle16_t(S_DEFRANGE_REGISTER_REL);
BytePrefix +=
StringRef(reinterpret_cast<const char *>(&SymKind), sizeof(SymKind));
BytePrefix +=
StringRef(reinterpret_cast<const char *>(&Sym.Header),
sizeof(Sym.Header) - sizeof(LocalVariableAddrRange));
} else {
assert(DefRange.DataOffset == 0 && "unexpected offset into register");
// Unclear what matters here.
DefRangeRegisterSym Sym(DefRange.CVRegister, 0, 0, 0, 0,
ArrayRef<LocalVariableAddrGap>());
ulittle16_t SymKind = ulittle16_t(S_DEFRANGE_REGISTER);
BytePrefix +=
StringRef(reinterpret_cast<const char *>(&SymKind), sizeof(SymKind));
BytePrefix +=
StringRef(reinterpret_cast<const char *>(&Sym.Header),
sizeof(Sym.Header) - sizeof(LocalVariableAddrRange));
}
OS.EmitCVDefRangeDirective(DefRange.Ranges, BytePrefix);
}
}
void CodeViewDebug::endFunction(const MachineFunction *MF) {
if (!Asm || !CurFn) // We haven't created any debug info for this function.
return;
const Function *GV = MF->getFunction();
assert(FnDebugInfo.count(GV));
assert(CurFn == &FnDebugInfo[GV]);
collectVariableInfo(GV->getSubprogram());
DebugHandlerBase::endFunction(MF);
// Don't emit anything if we don't have any line tables.
if (!CurFn->HaveLineInfo) {
FnDebugInfo.erase(GV);
CurFn = nullptr;
return;
}
CurFn->End = Asm->getFunctionEnd();
CurFn = nullptr;
}
void CodeViewDebug::beginInstruction(const MachineInstr *MI) {
DebugHandlerBase::beginInstruction(MI);
// Ignore DBG_VALUE locations and function prologue.
if (!Asm || MI->isDebugValue() || MI->getFlag(MachineInstr::FrameSetup))
return;
DebugLoc DL = MI->getDebugLoc();
if (DL == PrevInstLoc || !DL)
return;
maybeRecordLocation(DL, Asm->MF);
}
MCSymbol *CodeViewDebug::beginCVSubsection(ModuleSubstreamKind Kind) {
MCSymbol *BeginLabel = MMI->getContext().createTempSymbol(),
*EndLabel = MMI->getContext().createTempSymbol();
OS.EmitIntValue(unsigned(Kind), 4);
OS.AddComment("Subsection size");
OS.emitAbsoluteSymbolDiff(EndLabel, BeginLabel, 4);
OS.EmitLabel(BeginLabel);
return EndLabel;
}
void CodeViewDebug::endCVSubsection(MCSymbol *EndLabel) {
OS.EmitLabel(EndLabel);
// Every subsection must be aligned to a 4-byte boundary.
OS.EmitValueToAlignment(4);
}
void CodeViewDebug::emitDebugInfoForGlobals() {
NamedMDNode *CUs = MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
for (const MDNode *Node : CUs->operands()) {
const auto *CU = cast<DICompileUnit>(Node);
// First, emit all globals that are not in a comdat in a single symbol
// substream. MSVC doesn't like it if the substream is empty, so only open
// it if we have at least one global to emit.
switchToDebugSectionForSymbol(nullptr);
MCSymbol *EndLabel = nullptr;
for (const DIGlobalVariable *G : CU->getGlobalVariables()) {
if (const auto *GV = dyn_cast<GlobalVariable>(G->getVariable()))
if (!GV->hasComdat()) {
if (!EndLabel) {
OS.AddComment("Symbol subsection for globals");
EndLabel = beginCVSubsection(ModuleSubstreamKind::Symbols);
}
emitDebugInfoForGlobal(G, Asm->getSymbol(GV));
}
}
if (EndLabel)
endCVSubsection(EndLabel);
// Second, emit each global that is in a comdat into its own .debug$S
// section along with its own symbol substream.
for (const DIGlobalVariable *G : CU->getGlobalVariables()) {
if (const auto *GV = dyn_cast<GlobalVariable>(G->getVariable())) {
if (GV->hasComdat()) {
MCSymbol *GVSym = Asm->getSymbol(GV);
OS.AddComment("Symbol subsection for " +
Twine(GlobalValue::getRealLinkageName(GV->getName())));
switchToDebugSectionForSymbol(GVSym);
EndLabel = beginCVSubsection(ModuleSubstreamKind::Symbols);
emitDebugInfoForGlobal(G, GVSym);
endCVSubsection(EndLabel);
}
}
}
}
}
void CodeViewDebug::emitDebugInfoForGlobal(const DIGlobalVariable *DIGV,
MCSymbol *GVSym) {
// DataSym record, see SymbolRecord.h for more info.
// FIXME: Thread local data, etc
MCSymbol *DataBegin = MMI->getContext().createTempSymbol(),
*DataEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Record length");
OS.emitAbsoluteSymbolDiff(DataEnd, DataBegin, 2);
OS.EmitLabel(DataBegin);
OS.AddComment("Record kind: S_GDATA32");
OS.EmitIntValue(unsigned(SymbolKind::S_GDATA32), 2);
OS.AddComment("Type");
OS.EmitIntValue(getCompleteTypeIndex(DIGV->getType()).getIndex(), 4);
OS.AddComment("DataOffset");
OS.EmitCOFFSecRel32(GVSym);
OS.AddComment("Segment");
OS.EmitCOFFSectionIndex(GVSym);
OS.AddComment("Name");
emitNullTerminatedSymbolName(OS, DIGV->getName());
OS.EmitLabel(DataEnd);
}
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