llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
Pete Cooper 1ac3fbac0f Remove llvm::getDISubprogram in favor of Function::getSubprogram
llvm::getDISubprogram walks the instructions in a function, looking for one in the scope of the current function, so that it can find the !dbg entry for the subprogram itself.

Now that !dbg is attached to functions, this should not be necessary. This patch changes all uses to just query the subprogram directly on the function.

Ideally this should be NFC, but in reality its possible that a function:

has no !dbg (in which case there's likely a bug somewhere in an opt pass), or
that none of the instructions had a scope referencing the function, so we used to not find the !dbg on the function but now we will

Reviewed by Duncan Exon Smith.

Differential Revision: http://reviews.llvm.org/D18074

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263184 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-11 02:14:16 +00:00

782 lines
27 KiB
C++

//===-- 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/Line.h"
#include "llvm/DebugInfo/CodeView/SymbolRecord.h"
#include "llvm/DebugInfo/CodeView/TypeIndex.h"
#include "llvm/DebugInfo/CodeView/TypeRecord.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/COFF.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 Insertion = CurFn->InlineSites.insert({InlinedAt, InlineSite()});
InlineSite *Site = &Insertion.first->second;
if (Insertion.second) {
Site->SiteFuncId = NextFuncId++;
Site->Inlinee = Inlinee;
InlinedSubprograms.insert(Inlinee);
}
return *Site;
}
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::endModule() {
if (FnDebugInfo.empty())
return;
emitTypeInformation();
// FIXME: For functions that are comdat, we should emit separate .debug$S
// sections that are comdat associative with the main function instead of
// having one big .debug$S section.
assert(Asm != nullptr);
OS.SwitchSection(Asm->getObjFileLowering().getCOFFDebugSymbolsSection());
OS.AddComment("Debug section magic");
OS.EmitIntValue(COFF::DEBUG_SECTION_MAGIC, 4);
// The COFF .debug$S section consists of several subsections, each starting
// with a 4-byte control code (e.g. 0xF1, 0xF2, etc) and then a 4-byte length
// of the payload followed by the payload itself. The subsections are 4-byte
// aligned.
// Make a subsection for all the inlined subprograms.
emitInlineeLinesSubsection();
// Emit per-function debug information.
for (auto &P : FnDebugInfo)
emitDebugInfoForFunction(P.first, P.second);
// This subsection holds a file index to offset in string table table.
OS.AddComment("File index to string table offset subsection");
OS.EmitCVFileChecksumsDirective();
// This subsection holds the string table.
OS.AddComment("String table");
OS.EmitCVStringTableDirective();
clear();
}
void CodeViewDebug::emitTypeInformation() {
// Start the .debug$T section with 0x4.
OS.SwitchSection(Asm->getObjFileLowering().getCOFFDebugTypesSection());
OS.AddComment("Debug section magic");
OS.EmitIntValue(COFF::DEBUG_SECTION_MAGIC, 4);
NamedMDNode *CU_Nodes =
MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
if (!CU_Nodes)
return;
// This type info currently only holds function ids for use with inline call
// frame info. All functions are assigned a simple 'void ()' type. Emit that
// type here.
TypeIndex ArgListIdx = getNextTypeIndex();
OS.AddComment("Type record length");
OS.EmitIntValue(2 + sizeof(ArgList), 2);
OS.AddComment("Leaf type: LF_ARGLIST");
OS.EmitIntValue(LF_ARGLIST, 2);
OS.AddComment("Number of arguments");
OS.EmitIntValue(0, 4);
TypeIndex VoidProcIdx = getNextTypeIndex();
OS.AddComment("Type record length");
OS.EmitIntValue(2 + sizeof(ProcedureType), 2);
OS.AddComment("Leaf type: LF_PROCEDURE");
OS.EmitIntValue(LF_PROCEDURE, 2);
OS.AddComment("Return type index");
OS.EmitIntValue(TypeIndex::Void().getIndex(), 4);
OS.AddComment("Calling convention");
OS.EmitIntValue(char(CallingConvention::NearC), 1);
OS.AddComment("Function options");
OS.EmitIntValue(char(FunctionOptions::None), 1);
OS.AddComment("# of parameters");
OS.EmitIntValue(0, 2);
OS.AddComment("Argument list type index");
OS.EmitIntValue(ArgListIdx.getIndex(), 4);
for (MDNode *N : CU_Nodes->operands()) {
auto *CUNode = cast<DICompileUnit>(N);
for (auto *SP : CUNode->getSubprograms()) {
StringRef DisplayName = SP->getDisplayName();
OS.AddComment("Type record length");
OS.EmitIntValue(2 + sizeof(FuncId) + DisplayName.size() + 1, 2);
OS.AddComment("Leaf type: LF_FUNC_ID");
OS.EmitIntValue(LF_FUNC_ID, 2);
OS.AddComment("Scope type index");
OS.EmitIntValue(TypeIndex().getIndex(), 4);
OS.AddComment("Function type");
OS.EmitIntValue(VoidProcIdx.getIndex(), 4);
{
SmallString<32> NullTerminatedString(DisplayName);
if (NullTerminatedString.empty() || NullTerminatedString.back() != '\0')
NullTerminatedString.push_back('\0');
OS.AddComment("Function name");
OS.EmitBytes(NullTerminatedString);
}
TypeIndex FuncIdIdx = getNextTypeIndex();
SubprogramToFuncId.insert(std::make_pair(SP, FuncIdIdx));
}
}
}
void CodeViewDebug::emitInlineeLinesSubsection() {
if (InlinedSubprograms.empty())
return;
MCSymbol *InlineBegin = MMI->getContext().createTempSymbol(),
*InlineEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Inlinee lines subsection");
OS.EmitIntValue(unsigned(ModuleSubstreamKind::InlineeLines), 4);
OS.AddComment("Subsection size");
OS.emitAbsoluteSymbolDiff(InlineEnd, InlineBegin, 4);
OS.EmitLabel(InlineBegin);
// 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) {
OS.AddBlankLine();
TypeIndex TypeId = SubprogramToFuncId[SP];
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(TypeId.getIndex(), 4);
OS.AddComment("Offset into filechecksum table");
OS.EmitIntValue(FileOffset, 4);
OS.AddComment("Starting line number");
OS.EmitIntValue(SP->getLine(), 4);
}
OS.EmitLabel(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(SubprogramToFuncId.count(Site.Inlinee));
TypeIndex InlineeIdx = SubprogramToFuncId[Site.Inlinee];
// SymbolRecord
OS.AddComment("Record length");
OS.emitAbsoluteSymbolDiff(InlineEnd, InlineBegin, 2); // RecordLength
OS.EmitLabel(InlineBegin);
OS.AddComment("Record kind: S_INLINESITE");
OS.EmitIntValue(SymbolRecordKind::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(SymbolRecordKind::S_INLINESITE_END, 2); // RecordKind
}
static void emitNullTerminatedString(MCStreamer &OS, StringRef S) {
SmallString<32> NullTerminatedString(S);
if (NullTerminatedString.empty() || NullTerminatedString.back() != '\0')
NullTerminatedString.push_back('\0');
OS.EmitBytes(NullTerminatedString);
}
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);
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.
MCSymbol *SymbolsBegin = MMI->getContext().createTempSymbol(),
*SymbolsEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Symbol subsection for " + Twine(FuncName));
OS.EmitIntValue(unsigned(ModuleSubstreamKind::Symbols), 4);
OS.AddComment("Subsection size");
OS.emitAbsoluteSymbolDiff(SymbolsEnd, SymbolsBegin, 4);
OS.EmitLabel(SymbolsBegin);
{
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(SymbolRecordKind::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(0, 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");
emitNullTerminatedString(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(SymbolRecordKind::S_PROC_ID_END), 2);
}
OS.EmitLabel(SymbolsEnd);
// Every subsection must be aligned to a 4-byte boundary.
OS.EmitValueToAlignment(4);
// 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);
}
}
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(SymbolRecordKind::S_LOCAL), 2);
uint16_t Flags = 0;
if (Var.DIVar->isParameter())
Flags |= LocalSym::IsParameter;
if (Var.DefRanges.empty())
Flags |= LocalSym::IsOptimizedOut;
OS.AddComment("TypeIndex");
OS.EmitIntValue(TypeIndex::Int32().getIndex(), 4);
OS.AddComment("Flags");
OS.EmitIntValue(Flags, 2);
emitNullTerminatedString(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{};
ulittle16_t SymKind = ulittle16_t(S_DEFRANGE_REGISTER_REL);
Sym.BaseRegister = DefRange.CVRegister;
Sym.Flags = 0; // Unclear what matters here.
Sym.BasePointerOffset = DefRange.DataOffset;
BytePrefix +=
StringRef(reinterpret_cast<const char *>(&SymKind), sizeof(SymKind));
BytePrefix += StringRef(reinterpret_cast<const char *>(&Sym),
sizeof(Sym) - sizeof(LocalVariableAddrRange));
} else {
assert(DefRange.DataOffset == 0 && "unexpected offset into register");
DefRangeRegisterSym Sym{};
ulittle16_t SymKind = ulittle16_t(S_DEFRANGE_REGISTER);
Sym.Register = DefRange.CVRegister;
Sym.MayHaveNoName = 0; // Unclear what matters here.
BytePrefix +=
StringRef(reinterpret_cast<const char *>(&SymKind), sizeof(SymKind));
BytePrefix += StringRef(reinterpret_cast<const char *>(&Sym),
sizeof(Sym) - 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);
}