mirrors/llvm-project
0
0
Fork 0
mirror of https://github.com/llvm/llvm-project.git synced 2025-05-05 17:16:06 +00:00
Code Issues Projects Releases Wiki Activity
llvm-project/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
Vedant Kumar e08f205f5c Reland (again): [DWARF] Allow cross-CU references of subprogram definitions 
This is a revert-of-revert (i.e. this reverts commit 802bec89, which
itself reverted fa4701e1 and 79daafc9) with a fix folded in. The problem
was that call site tags weren't emitted properly when LTO was enabled
along with split-dwarf. This required a minor fix. I've added a reduced
test case in test/DebugInfo/X86/fission-call-site.ll.

Original commit message:

This allows a call site tag in CU A to reference a callee DIE in CU B
without resorting to creating an incomplete duplicate DIE for the callee
inside of CU A.

We already allow cross-CU references of subprogram declarations, so it
doesn't seem like definitions ought to be special.

This improves entry value evaluation and tail call frame synthesis in
the LTO setting. During LTO, it's common for cross-module inlining to
produce a call in some CU A where the callee resides in a different CU,
and there is no declaration subprogram for the callee anywhere. In this
case llvm would (unnecessarily, I think) emit an empty DW_TAG_subprogram
in order to fill in the call site tag. That empty 'definition' defeats
entry value evaluation etc., because the debugger can't figure out what
it means.

As a follow-up, maybe we could add a DWARF verifier check that a
DW_TAG_subprogram at least has a DW_AT_name attribute.

Update #1:

Reland with a fix to create a declaration DIE when the declaration is
missing from the CU's retainedTypes list. The declaration is left out
of the retainedTypes list in two cases:

1) Re-compiling pre-r266445 bitcode (in which declarations weren't added
   to the retainedTypes list), and
2) Doing LTO function importing (which doesn't update the retainedTypes
   list).

It's possible to handle (1) and (2) by modifying the retainedTypes list
(in AutoUpgrade, or in the LTO importing logic resp.), but I don't see
an advantage to doing it this way, as it would cause more DWARF to be
emitted compared to creating the declaration DIEs lazily.

Update #2:

Fold in a fix for call site tag emission in the split-dwarf + LTO case.

Tested with a stage2 ThinLTO+RelWithDebInfo build of clang, and with a
ReleaseLTO-g build of the test suite.

rdar://46577651, rdar://57855316, rdar://57840415, rdar://58888440

Differential Revision: https://reviews.llvm.org/D70350
2020-01-27 10:52:34 -08:00

1363 lines
51 KiB
C++
Raw Blame History

//===- llvm/CodeGen/DwarfCompileUnit.cpp - Dwarf Compile Units ------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains support for constructing a dwarf compile unit.
//
//===----------------------------------------------------------------------===//
#include "DwarfCompileUnit.h"
#include "AddressPool.h"
#include "DwarfDebug.h"
#include "DwarfExpression.h"
#include "DwarfUnit.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/DIE.h"
#include "llvm/CodeGen/LexicalScopes.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MachineLocation.h"
#include "llvm/Support/Casting.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <iterator>
#include <memory>
#include <string>
#include <utility>
using namespace llvm;
static dwarf::Tag GetCompileUnitType(UnitKind Kind, DwarfDebug *DW) {
// According to DWARF Debugging Information Format Version 5,
// 3.1.2 Skeleton Compilation Unit Entries:
// "When generating a split DWARF object file (see Section 7.3.2
// on page 187), the compilation unit in the .debug_info section
// is a "skeleton" compilation unit with the tag DW_TAG_skeleton_unit"
if (DW->getDwarfVersion() >= 5 && Kind == UnitKind::Skeleton)
return dwarf::DW_TAG_skeleton_unit;
return dwarf::DW_TAG_compile_unit;
}
DwarfCompileUnit::DwarfCompileUnit(unsigned UID, const DICompileUnit *Node,
AsmPrinter *A, DwarfDebug *DW,
DwarfFile *DWU, UnitKind Kind)
: DwarfUnit(GetCompileUnitType(Kind, DW), Node, A, DW, DWU), UniqueID(UID) {
insertDIE(Node, &getUnitDie());
MacroLabelBegin = Asm->createTempSymbol("cu_macro_begin");
}
/// addLabelAddress - Add a dwarf label attribute data and value using
/// DW_FORM_addr or DW_FORM_GNU_addr_index.
void DwarfCompileUnit::addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Label) {
// Don't use the address pool in non-fission or in the skeleton unit itself.
if ((!DD->useSplitDwarf() || !Skeleton) && DD->getDwarfVersion() < 5)
return addLocalLabelAddress(Die, Attribute, Label);
if (Label)
DD->addArangeLabel(SymbolCU(this, Label));
unsigned idx = DD->getAddressPool().getIndex(Label);
Die.addValue(DIEValueAllocator, Attribute,
DD->getDwarfVersion() >= 5 ? dwarf::DW_FORM_addrx
: dwarf::DW_FORM_GNU_addr_index,
DIEInteger(idx));
}
void DwarfCompileUnit::addLocalLabelAddress(DIE &Die,
dwarf::Attribute Attribute,
const MCSymbol *Label) {
if (Label)
DD->addArangeLabel(SymbolCU(this, Label));
if (Label)
Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
DIELabel(Label));
else
Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
DIEInteger(0));
}
unsigned DwarfCompileUnit::getOrCreateSourceID(const DIFile *File) {
// If we print assembly, we can't separate .file entries according to
// compile units. Thus all files will belong to the default compile unit.
// FIXME: add a better feature test than hasRawTextSupport. Even better,
// extend .file to support this.
unsigned CUID = Asm->OutStreamer->hasRawTextSupport() ? 0 : getUniqueID();
if (!File)
return Asm->OutStreamer->EmitDwarfFileDirective(0, "", "", None, None, CUID);
return Asm->OutStreamer->EmitDwarfFileDirective(
0, File->getDirectory(), File->getFilename(), getMD5AsBytes(File),
File->getSource(), CUID);
}
DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(
const DIGlobalVariable *GV, ArrayRef<GlobalExpr> GlobalExprs) {
// Check for pre-existence.
if (DIE *Die = getDIE(GV))
return Die;
assert(GV);
auto *GVContext = GV->getScope();
const DIType *GTy = GV->getType();
// Construct the context before querying for the existence of the DIE in
// case such construction creates the DIE.
auto *CB = GVContext ? dyn_cast<DICommonBlock>(GVContext) : nullptr;
DIE *ContextDIE = CB ? getOrCreateCommonBlock(CB, GlobalExprs)
: getOrCreateContextDIE(GVContext);
// Add to map.
DIE *VariableDIE = &createAndAddDIE(GV->getTag(), *ContextDIE, GV);
DIScope *DeclContext;
if (auto *SDMDecl = GV->getStaticDataMemberDeclaration()) {
DeclContext = SDMDecl->getScope();
assert(SDMDecl->isStaticMember() && "Expected static member decl");
assert(GV->isDefinition());
// We need the declaration DIE that is in the static member's class.
DIE *VariableSpecDIE = getOrCreateStaticMemberDIE(SDMDecl);
addDIEEntry(*VariableDIE, dwarf::DW_AT_specification, *VariableSpecDIE);
// If the global variable's type is different from the one in the class
// member type, assume that it's more specific and also emit it.
if (GTy != SDMDecl->getBaseType())
addType(*VariableDIE, GTy);
} else {
DeclContext = GV->getScope();
// Add name and type.
addString(*VariableDIE, dwarf::DW_AT_name, GV->getDisplayName());
addType(*VariableDIE, GTy);
// Add scoping info.
if (!GV->isLocalToUnit())
addFlag(*VariableDIE, dwarf::DW_AT_external);
// Add line number info.
addSourceLine(*VariableDIE, GV);
}
if (!GV->isDefinition())
addFlag(*VariableDIE, dwarf::DW_AT_declaration);
else
addGlobalName(GV->getName(), *VariableDIE, DeclContext);
if (uint32_t AlignInBytes = GV->getAlignInBytes())
addUInt(*VariableDIE, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
AlignInBytes);
if (MDTuple *TP = GV->getTemplateParams())
addTemplateParams(*VariableDIE, DINodeArray(TP));
// Add location.
addLocationAttribute(VariableDIE, GV, GlobalExprs);
return VariableDIE;
}
void DwarfCompileUnit::addLocationAttribute(
DIE *VariableDIE, const DIGlobalVariable *GV, ArrayRef<GlobalExpr> GlobalExprs) {
bool addToAccelTable = false;
DIELoc *Loc = nullptr;
Optional<unsigned> NVPTXAddressSpace;
std::unique_ptr<DIEDwarfExpression> DwarfExpr;
for (const auto &GE : GlobalExprs) {
const GlobalVariable *Global = GE.Var;
const DIExpression *Expr = GE.Expr;
// For compatibility with DWARF 3 and earlier,
// DW_AT_location(DW_OP_constu, X, DW_OP_stack_value) becomes
// DW_AT_const_value(X).
if (GlobalExprs.size() == 1 && Expr && Expr->isConstant()) {
addToAccelTable = true;
addConstantValue(*VariableDIE, /*Unsigned=*/true, Expr->getElement(1));
break;
}
// We cannot describe the location of dllimport'd variables: the
// computation of their address requires loads from the IAT.
if (Global && Global->hasDLLImportStorageClass())
continue;
// Nothing to describe without address or constant.
if (!Global && (!Expr || !Expr->isConstant()))
continue;
if (Global && Global->isThreadLocal() &&
!Asm->getObjFileLowering().supportDebugThreadLocalLocation())
continue;
if (!Loc) {
addToAccelTable = true;
Loc = new (DIEValueAllocator) DIELoc;
DwarfExpr = std::make_unique<DIEDwarfExpression>(*Asm, *this, *Loc);
}
if (Expr) {
// According to
// https://docs.nvidia.com/cuda/archive/10.0/ptx-writers-guide-to-interoperability/index.html#cuda-specific-dwarf
// cuda-gdb requires DW_AT_address_class for all variables to be able to
// correctly interpret address space of the variable address.
// Decode DW_OP_constu <DWARF Address Space> DW_OP_swap DW_OP_xderef
// sequence for the NVPTX + gdb target.
unsigned LocalNVPTXAddressSpace;
if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB()) {
const DIExpression *NewExpr =
DIExpression::extractAddressClass(Expr, LocalNVPTXAddressSpace);
if (NewExpr != Expr) {
Expr = NewExpr;
NVPTXAddressSpace = LocalNVPTXAddressSpace;
}
}
DwarfExpr->addFragmentOffset(Expr);
}
if (Global) {
const MCSymbol *Sym = Asm->getSymbol(Global);
if (Global->isThreadLocal()) {
if (Asm->TM.useEmulatedTLS()) {
// TODO: add debug info for emulated thread local mode.
} else {
// FIXME: Make this work with -gsplit-dwarf.
unsigned PointerSize = Asm->getDataLayout().getPointerSize();
assert((PointerSize == 4 || PointerSize == 8) &&
"Add support for other sizes if necessary");
// Based on GCC's support for TLS:
if (!DD->useSplitDwarf()) {
// 1) Start with a constNu of the appropriate pointer size
addUInt(*Loc, dwarf::DW_FORM_data1,
PointerSize == 4 ? dwarf::DW_OP_const4u
: dwarf::DW_OP_const8u);
// 2) containing the (relocated) offset of the TLS variable
// within the module's TLS block.
addExpr(*Loc, dwarf::DW_FORM_udata,
Asm->getObjFileLowering().getDebugThreadLocalSymbol(Sym));
} else {
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_const_index);
addUInt(*Loc, dwarf::DW_FORM_udata,
DD->getAddressPool().getIndex(Sym, /* TLS */ true));
}
// 3) followed by an OP to make the debugger do a TLS lookup.
addUInt(*Loc, dwarf::DW_FORM_data1,
DD->useGNUTLSOpcode() ? dwarf::DW_OP_GNU_push_tls_address
: dwarf::DW_OP_form_tls_address);
}
} else {
DD->addArangeLabel(SymbolCU(this, Sym));
addOpAddress(*Loc, Sym);
}
}
// Global variables attached to symbols are memory locations.
// It would be better if this were unconditional, but malformed input that
// mixes non-fragments and fragments for the same variable is too expensive
// to detect in the verifier.
if (DwarfExpr->isUnknownLocation())
DwarfExpr->setMemoryLocationKind();
DwarfExpr->addExpression(Expr);
}
if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB()) {
// According to
// https://docs.nvidia.com/cuda/archive/10.0/ptx-writers-guide-to-interoperability/index.html#cuda-specific-dwarf
// cuda-gdb requires DW_AT_address_class for all variables to be able to
// correctly interpret address space of the variable address.
const unsigned NVPTX_ADDR_global_space = 5;
addUInt(*VariableDIE, dwarf::DW_AT_address_class, dwarf::DW_FORM_data1,
NVPTXAddressSpace ? *NVPTXAddressSpace : NVPTX_ADDR_global_space);
}
if (Loc)
addBlock(*VariableDIE, dwarf::DW_AT_location, DwarfExpr->finalize());
if (DD->useAllLinkageNames())
addLinkageName(*VariableDIE, GV->getLinkageName());
if (addToAccelTable) {
DD->addAccelName(*CUNode, GV->getName(), *VariableDIE);
// If the linkage name is different than the name, go ahead and output
// that as well into the name table.
if (GV->getLinkageName() != "" && GV->getName() != GV->getLinkageName() &&
DD->useAllLinkageNames())
DD->addAccelName(*CUNode, GV->getLinkageName(), *VariableDIE);
}
}
DIE *DwarfCompileUnit::getOrCreateCommonBlock(
const DICommonBlock *CB, ArrayRef<GlobalExpr> GlobalExprs) {
// Construct the context before querying for the existence of the DIE in case
// such construction creates the DIE.
DIE *ContextDIE = getOrCreateContextDIE(CB->getScope());
if (DIE *NDie = getDIE(CB))
return NDie;
DIE &NDie = createAndAddDIE(dwarf::DW_TAG_common_block, *ContextDIE, CB);
StringRef Name = CB->getName().empty() ? "_BLNK_" : CB->getName();
addString(NDie, dwarf::DW_AT_name, Name);
addGlobalName(Name, NDie, CB->getScope());
if (CB->getFile())
addSourceLine(NDie, CB->getLineNo(), CB->getFile());
if (DIGlobalVariable *V = CB->getDecl())
getCU().addLocationAttribute(&NDie, V, GlobalExprs);
return &NDie;
}
void DwarfCompileUnit::addRange(RangeSpan Range) {
DD->insertSectionLabel(Range.Begin);
bool SameAsPrevCU = this == DD->getPrevCU();
DD->setPrevCU(this);
// If we have no current ranges just add the range and return, otherwise,
// check the current section and CU against the previous section and CU we
// emitted into and the subprogram was contained within. If these are the
// same then extend our current range, otherwise add this as a new range.
if (CURanges.empty() || !SameAsPrevCU ||
(&CURanges.back().End->getSection() !=
&Range.End->getSection())) {
CURanges.push_back(Range);
return;
}
CURanges.back().End = Range.End;
}
void DwarfCompileUnit::initStmtList() {
if (CUNode->isDebugDirectivesOnly())
return;
// Define start line table label for each Compile Unit.
MCSymbol *LineTableStartSym;
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
if (DD->useSectionsAsReferences()) {
LineTableStartSym = TLOF.getDwarfLineSection()->getBeginSymbol();
} else {
LineTableStartSym =
Asm->OutStreamer->getDwarfLineTableSymbol(getUniqueID());
}
// DW_AT_stmt_list is a offset of line number information for this
// compile unit in debug_line section. For split dwarf this is
// left in the skeleton CU and so not included.
// The line table entries are not always emitted in assembly, so it
// is not okay to use line_table_start here.
StmtListValue =
addSectionLabel(getUnitDie(), dwarf::DW_AT_stmt_list, LineTableStartSym,
TLOF.getDwarfLineSection()->getBeginSymbol());
}
void DwarfCompileUnit::applyStmtList(DIE &D) {
D.addValue(DIEValueAllocator, *StmtListValue);
}
void DwarfCompileUnit::attachLowHighPC(DIE &D, const MCSymbol *Begin,
const MCSymbol *End) {
assert(Begin && "Begin label should not be null!");
assert(End && "End label should not be null!");
assert(Begin->isDefined() && "Invalid starting label");
assert(End->isDefined() && "Invalid end label");
addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
if (DD->getDwarfVersion() < 4)
addLabelAddress(D, dwarf::DW_AT_high_pc, End);
else
addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
}
// Find DIE for the given subprogram and attach appropriate DW_AT_low_pc
// and DW_AT_high_pc attributes. If there are global variables in this
// scope then create and insert DIEs for these variables.
DIE &DwarfCompileUnit::updateSubprogramScopeDIE(const DISubprogram *SP) {
DIE *SPDie = getOrCreateSubprogramDIE(SP, includeMinimalInlineScopes());
attachLowHighPC(*SPDie, Asm->getFunctionBegin(), Asm->getFunctionEnd());
if (DD->useAppleExtensionAttributes() &&
!DD->getCurrentFunction()->getTarget().Options.DisableFramePointerElim(
*DD->getCurrentFunction()))
addFlag(*SPDie, dwarf::DW_AT_APPLE_omit_frame_ptr);
// Only include DW_AT_frame_base in full debug info
if (!includeMinimalInlineScopes()) {
const TargetFrameLowering *TFI = Asm->MF->getSubtarget().getFrameLowering();
TargetFrameLowering::DwarfFrameBase FrameBase =
TFI->getDwarfFrameBase(*Asm->MF);
switch (FrameBase.Kind) {
case TargetFrameLowering::DwarfFrameBase::Register: {
if (Register::isPhysicalRegister(FrameBase.Location.Reg)) {
MachineLocation Location(FrameBase.Location.Reg);
addAddress(*SPDie, dwarf::DW_AT_frame_base, Location);
}
break;
}
case TargetFrameLowering::DwarfFrameBase::CFA: {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_call_frame_cfa);
addBlock(*SPDie, dwarf::DW_AT_frame_base, Loc);
break;
}
case TargetFrameLowering::DwarfFrameBase::WasmFrameBase: {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
DIExpressionCursor Cursor({});
DwarfExpr.addWasmLocation(FrameBase.Location.WasmLoc.Kind,
FrameBase.Location.WasmLoc.Index);
DwarfExpr.addExpression(std::move(Cursor));
addBlock(*SPDie, dwarf::DW_AT_frame_base, DwarfExpr.finalize());
break;
}
}
}
// Add name to the name table, we do this here because we're guaranteed
// to have concrete versions of our DW_TAG_subprogram nodes.
DD->addSubprogramNames(*CUNode, SP, *SPDie);
return *SPDie;
}
// Construct a DIE for this scope.
void DwarfCompileUnit::constructScopeDIE(
LexicalScope *Scope, SmallVectorImpl<DIE *> &FinalChildren) {
if (!Scope || !Scope->getScopeNode())
return;
auto *DS = Scope->getScopeNode();
assert((Scope->getInlinedAt() || !isa<DISubprogram>(DS)) &&
"Only handle inlined subprograms here, use "
"constructSubprogramScopeDIE for non-inlined "
"subprograms");
SmallVector<DIE *, 8> Children;
// We try to create the scope DIE first, then the children DIEs. This will
// avoid creating un-used children then removing them later when we find out
// the scope DIE is null.
DIE *ScopeDIE;
if (Scope->getParent() && isa<DISubprogram>(DS)) {
ScopeDIE = constructInlinedScopeDIE(Scope);
if (!ScopeDIE)
return;
// We create children when the scope DIE is not null.
createScopeChildrenDIE(Scope, Children);
} else {
// Early exit when we know the scope DIE is going to be null.
if (DD->isLexicalScopeDIENull(Scope))
return;
bool HasNonScopeChildren = false;
// We create children here when we know the scope DIE is not going to be
// null and the children will be added to the scope DIE.
createScopeChildrenDIE(Scope, Children, &HasNonScopeChildren);
// If there are only other scopes as children, put them directly in the
// parent instead, as this scope would serve no purpose.
if (!HasNonScopeChildren) {
FinalChildren.insert(FinalChildren.end(),
std::make_move_iterator(Children.begin()),
std::make_move_iterator(Children.end()));
return;
}
ScopeDIE = constructLexicalScopeDIE(Scope);
assert(ScopeDIE && "Scope DIE should not be null.");
}
// Add children
for (auto &I : Children)
ScopeDIE->addChild(std::move(I));
FinalChildren.push_back(std::move(ScopeDIE));
}
void DwarfCompileUnit::addScopeRangeList(DIE &ScopeDIE,
SmallVector<RangeSpan, 2> Range) {
HasRangeLists = true;
// Add the range list to the set of ranges to be emitted.
auto IndexAndList =
(DD->getDwarfVersion() < 5 && Skeleton ? Skeleton->DU : DU)
->addRange(*(Skeleton ? Skeleton : this), std::move(Range));
uint32_t Index = IndexAndList.first;
auto &List = *IndexAndList.second;
// Under fission, ranges are specified by constant offsets relative to the
// CU's DW_AT_GNU_ranges_base.
// FIXME: For DWARF v5, do not generate the DW_AT_ranges attribute under
// fission until we support the forms using the .debug_addr section
// (DW_RLE_startx_endx etc.).
if (DD->getDwarfVersion() >= 5)
addUInt(ScopeDIE, dwarf::DW_AT_ranges, dwarf::DW_FORM_rnglistx, Index);
else {
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
const MCSymbol *RangeSectionSym =
TLOF.getDwarfRangesSection()->getBeginSymbol();
if (isDwoUnit())
addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, List.Label,
RangeSectionSym);
else
addSectionLabel(ScopeDIE, dwarf::DW_AT_ranges, List.Label,
RangeSectionSym);
}
}
void DwarfCompileUnit::attachRangesOrLowHighPC(
DIE &Die, SmallVector<RangeSpan, 2> Ranges) {
if (Ranges.size() == 1 || !DD->useRangesSection()) {
const RangeSpan &Front = Ranges.front();
const RangeSpan &Back = Ranges.back();
attachLowHighPC(Die, Front.Begin, Back.End);
} else
addScopeRangeList(Die, std::move(Ranges));
}
void DwarfCompileUnit::attachRangesOrLowHighPC(
DIE &Die, const SmallVectorImpl<InsnRange> &Ranges) {
SmallVector<RangeSpan, 2> List;
List.reserve(Ranges.size());
for (const InsnRange &R : Ranges)
List.push_back(
{DD->getLabelBeforeInsn(R.first), DD->getLabelAfterInsn(R.second)});
attachRangesOrLowHighPC(Die, std::move(List));
}
// This scope represents inlined body of a function. Construct DIE to
// represent this concrete inlined copy of the function.
DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope) {
assert(Scope->getScopeNode());
auto *DS = Scope->getScopeNode();
auto *InlinedSP = getDISubprogram(DS);
// Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
// was inlined from another compile unit.
DIE *OriginDIE = getAbstractSPDies()[InlinedSP];
assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_inlined_subroutine);
addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
// Add the call site information to the DIE.
const DILocation *IA = Scope->getInlinedAt();
addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
getOrCreateSourceID(IA->getFile()));
addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, IA->getLine());
if (IA->getColumn())
addUInt(*ScopeDIE, dwarf::DW_AT_call_column, None, IA->getColumn());
if (IA->getDiscriminator() && DD->getDwarfVersion() >= 4)
addUInt(*ScopeDIE, dwarf::DW_AT_GNU_discriminator, None,
IA->getDiscriminator());
// Add name to the name table, we do this here because we're guaranteed
// to have concrete versions of our DW_TAG_inlined_subprogram nodes.
DD->addSubprogramNames(*CUNode, InlinedSP, *ScopeDIE);
return ScopeDIE;
}
// Construct new DW_TAG_lexical_block for this scope and attach
// DW_AT_low_pc/DW_AT_high_pc labels.
DIE *DwarfCompileUnit::constructLexicalScopeDIE(LexicalScope *Scope) {
if (DD->isLexicalScopeDIENull(Scope))
return nullptr;
auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_lexical_block);
if (Scope->isAbstractScope())
return ScopeDIE;
attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
return ScopeDIE;
}
/// constructVariableDIE - Construct a DIE for the given DbgVariable.
DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV, bool Abstract) {
auto D = constructVariableDIEImpl(DV, Abstract);
DV.setDIE(*D);
return D;
}
DIE *DwarfCompileUnit::constructLabelDIE(DbgLabel &DL,
const LexicalScope &Scope) {
auto LabelDie = DIE::get(DIEValueAllocator, DL.getTag());
insertDIE(DL.getLabel(), LabelDie);
DL.setDIE(*LabelDie);
if (Scope.isAbstractScope())
applyLabelAttributes(DL, *LabelDie);
return LabelDie;
}
DIE *DwarfCompileUnit::constructVariableDIEImpl(const DbgVariable &DV,
bool Abstract) {
// Define variable debug information entry.
auto VariableDie = DIE::get(DIEValueAllocator, DV.getTag());
insertDIE(DV.getVariable(), VariableDie);
if (Abstract) {
applyVariableAttributes(DV, *VariableDie);
return VariableDie;
}
// Add variable address.
unsigned Offset = DV.getDebugLocListIndex();
if (Offset != ~0U) {
addLocationList(*VariableDie, dwarf::DW_AT_location, Offset);
auto TagOffset = DV.getDebugLocListTagOffset();
if (TagOffset)
addUInt(*VariableDie, dwarf::DW_AT_LLVM_tag_offset, dwarf::DW_FORM_data1,
*TagOffset);
return VariableDie;
}
// Check if variable has a single location description.
if (auto *DVal = DV.getValueLoc()) {
if (DVal->isLocation())
addVariableAddress(DV, *VariableDie, DVal->getLoc());
else if (DVal->isInt()) {
auto *Expr = DV.getSingleExpression();
if (Expr && Expr->getNumElements()) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
// If there is an expression, emit raw unsigned bytes.
DwarfExpr.addFragmentOffset(Expr);
DwarfExpr.addUnsignedConstant(DVal->getInt());
DwarfExpr.addExpression(Expr);
addBlock(*VariableDie, dwarf::DW_AT_location, DwarfExpr.finalize());
if (DwarfExpr.TagOffset)
addUInt(*VariableDie, dwarf::DW_AT_LLVM_tag_offset,
dwarf::DW_FORM_data1, *DwarfExpr.TagOffset);
} else
addConstantValue(*VariableDie, DVal->getInt(), DV.getType());
} else if (DVal->isConstantFP()) {
addConstantFPValue(*VariableDie, DVal->getConstantFP());
} else if (DVal->isConstantInt()) {
addConstantValue(*VariableDie, DVal->getConstantInt(), DV.getType());
}
return VariableDie;
}
// .. else use frame index.
if (!DV.hasFrameIndexExprs())
return VariableDie;
Optional<unsigned> NVPTXAddressSpace;
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
for (auto &Fragment : DV.getFrameIndexExprs()) {
unsigned FrameReg = 0;
const DIExpression *Expr = Fragment.Expr;
const TargetFrameLowering *TFI = Asm->MF->getSubtarget().getFrameLowering();
int Offset = TFI->getFrameIndexReference(*Asm->MF, Fragment.FI, FrameReg);
DwarfExpr.addFragmentOffset(Expr);
SmallVector<uint64_t, 8> Ops;
DIExpression::appendOffset(Ops, Offset);
// According to
// https://docs.nvidia.com/cuda/archive/10.0/ptx-writers-guide-to-interoperability/index.html#cuda-specific-dwarf
// cuda-gdb requires DW_AT_address_class for all variables to be able to
// correctly interpret address space of the variable address.
// Decode DW_OP_constu <DWARF Address Space> DW_OP_swap DW_OP_xderef
// sequence for the NVPTX + gdb target.
unsigned LocalNVPTXAddressSpace;
if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB()) {
const DIExpression *NewExpr =
DIExpression::extractAddressClass(Expr, LocalNVPTXAddressSpace);
if (NewExpr != Expr) {
Expr = NewExpr;
NVPTXAddressSpace = LocalNVPTXAddressSpace;
}
}
if (Expr)
Ops.append(Expr->elements_begin(), Expr->elements_end());
DIExpressionCursor Cursor(Ops);
DwarfExpr.setMemoryLocationKind();
if (const MCSymbol *FrameSymbol = Asm->getFunctionFrameSymbol())
addOpAddress(*Loc, FrameSymbol);
else
DwarfExpr.addMachineRegExpression(
*Asm->MF->getSubtarget().getRegisterInfo(), Cursor, FrameReg);
DwarfExpr.addExpression(std::move(Cursor));
}
if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB()) {
// According to
// https://docs.nvidia.com/cuda/archive/10.0/ptx-writers-guide-to-interoperability/index.html#cuda-specific-dwarf
// cuda-gdb requires DW_AT_address_class for all variables to be able to
// correctly interpret address space of the variable address.
const unsigned NVPTX_ADDR_local_space = 6;
addUInt(*VariableDie, dwarf::DW_AT_address_class, dwarf::DW_FORM_data1,
NVPTXAddressSpace ? *NVPTXAddressSpace : NVPTX_ADDR_local_space);
}
addBlock(*VariableDie, dwarf::DW_AT_location, DwarfExpr.finalize());
if (DwarfExpr.TagOffset)
addUInt(*VariableDie, dwarf::DW_AT_LLVM_tag_offset, dwarf::DW_FORM_data1,
*DwarfExpr.TagOffset);
return VariableDie;
}
DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV,
const LexicalScope &Scope,
DIE *&ObjectPointer) {
auto Var = constructVariableDIE(DV, Scope.isAbstractScope());
if (DV.isObjectPointer())
ObjectPointer = Var;
return Var;
}
/// Return all DIVariables that appear in count: expressions.
static SmallVector<const DIVariable *, 2> dependencies(DbgVariable *Var) {
SmallVector<const DIVariable *, 2> Result;
auto *Array = dyn_cast<DICompositeType>(Var->getType());
if (!Array || Array->getTag() != dwarf::DW_TAG_array_type)
return Result;
for (auto *El : Array->getElements()) {
if (auto *Subrange = dyn_cast<DISubrange>(El)) {
auto Count = Subrange->getCount();
if (auto *Dependency = Count.dyn_cast<DIVariable *>())
Result.push_back(Dependency);
}
}
return Result;
}
/// Sort local variables so that variables appearing inside of helper
/// expressions come first.
static SmallVector<DbgVariable *, 8>
sortLocalVars(SmallVectorImpl<DbgVariable *> &Input) {
SmallVector<DbgVariable *, 8> Result;
SmallVector<PointerIntPair<DbgVariable *, 1>, 8> WorkList;
// Map back from a DIVariable to its containing DbgVariable.
SmallDenseMap<const DILocalVariable *, DbgVariable *> DbgVar;
// Set of DbgVariables in Result.
SmallDenseSet<DbgVariable *, 8> Visited;
// For cycle detection.
SmallDenseSet<DbgVariable *, 8> Visiting;
// Initialize the worklist and the DIVariable lookup table.
for (auto Var : reverse(Input)) {
DbgVar.insert({Var->getVariable(), Var});
WorkList.push_back({Var, 0});
}
// Perform a stable topological sort by doing a DFS.
while (!WorkList.empty()) {
auto Item = WorkList.back();
DbgVariable *Var = Item.getPointer();
bool visitedAllDependencies = Item.getInt();
WorkList.pop_back();
// Dependency is in a different lexical scope or a global.
if (!Var)
continue;
// Already handled.
if (Visited.count(Var))
continue;
// Add to Result if all dependencies are visited.
if (visitedAllDependencies) {
Visited.insert(Var);
Result.push_back(Var);
continue;
}
// Detect cycles.
auto Res = Visiting.insert(Var);
if (!Res.second) {
assert(false && "dependency cycle in local variables");
return Result;
}
// Push dependencies and this node onto the worklist, so that this node is
// visited again after all of its dependencies are handled.
WorkList.push_back({Var, 1});
for (auto *Dependency : dependencies(Var)) {
auto Dep = dyn_cast_or_null<const DILocalVariable>(Dependency);
WorkList.push_back({DbgVar[Dep], 0});
}
}
return Result;
}
DIE *DwarfCompileUnit::createScopeChildrenDIE(LexicalScope *Scope,
SmallVectorImpl<DIE *> &Children,
bool *HasNonScopeChildren) {
assert(Children.empty());
DIE *ObjectPointer = nullptr;
// Emit function arguments (order is significant).
auto Vars = DU->getScopeVariables().lookup(Scope);
for (auto &DV : Vars.Args)
Children.push_back(constructVariableDIE(*DV.second, *Scope, ObjectPointer));
// Emit local variables.
auto Locals = sortLocalVars(Vars.Locals);
for (DbgVariable *DV : Locals)
Children.push_back(constructVariableDIE(*DV, *Scope, ObjectPointer));
// Skip imported directives in gmlt-like data.
if (!includeMinimalInlineScopes()) {
// There is no need to emit empty lexical block DIE.
for (const auto *IE : ImportedEntities[Scope->getScopeNode()])
Children.push_back(
constructImportedEntityDIE(cast<DIImportedEntity>(IE)));
}
if (HasNonScopeChildren)
*HasNonScopeChildren = !Children.empty();
for (DbgLabel *DL : DU->getScopeLabels().lookup(Scope))
Children.push_back(constructLabelDIE(*DL, *Scope));
for (LexicalScope *LS : Scope->getChildren())
constructScopeDIE(LS, Children);
return ObjectPointer;
}
DIE &DwarfCompileUnit::constructSubprogramScopeDIE(const DISubprogram *Sub,
LexicalScope *Scope) {
DIE &ScopeDIE = updateSubprogramScopeDIE(Sub);
if (Scope) {
assert(!Scope->getInlinedAt());
assert(!Scope->isAbstractScope());
// Collect lexical scope children first.
// ObjectPointer might be a local (non-argument) local variable if it's a
// block's synthetic this pointer.
if (DIE *ObjectPointer = createAndAddScopeChildren(Scope, ScopeDIE))
addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer);
}
// If this is a variadic function, add an unspecified parameter.
DITypeRefArray FnArgs = Sub->getType()->getTypeArray();
// If we have a single element of null, it is a function that returns void.
// If we have more than one elements and the last one is null, it is a
// variadic function.
if (FnArgs.size() > 1 && !FnArgs[FnArgs.size() - 1] &&
!includeMinimalInlineScopes())
ScopeDIE.addChild(
DIE::get(DIEValueAllocator, dwarf::DW_TAG_unspecified_parameters));
return ScopeDIE;
}
DIE *DwarfCompileUnit::createAndAddScopeChildren(LexicalScope *Scope,
DIE &ScopeDIE) {
// We create children when the scope DIE is not null.
SmallVector<DIE *, 8> Children;
DIE *ObjectPointer = createScopeChildrenDIE(Scope, Children);
// Add children
for (auto &I : Children)
ScopeDIE.addChild(std::move(I));
return ObjectPointer;
}
void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
LexicalScope *Scope) {
DIE *&AbsDef = getAbstractSPDies()[Scope->getScopeNode()];
if (AbsDef)
return;
auto *SP = cast<DISubprogram>(Scope->getScopeNode());
DIE *ContextDIE;
DwarfCompileUnit *ContextCU = this;
if (includeMinimalInlineScopes())
ContextDIE = &getUnitDie();
// Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
// the important distinction that the debug node is not associated with the
// DIE (since the debug node will be associated with the concrete DIE, if
// any). It could be refactored to some common utility function.
else if (auto *SPDecl = SP->getDeclaration()) {
ContextDIE = &getUnitDie();
getOrCreateSubprogramDIE(SPDecl);
} else {
ContextDIE = getOrCreateContextDIE(SP->getScope());
// The scope may be shared with a subprogram that has already been
// constructed in another CU, in which case we need to construct this
// subprogram in the same CU.
ContextCU = DD->lookupCU(ContextDIE->getUnitDie());
}
// Passing null as the associated node because the abstract definition
// shouldn't be found by lookup.
AbsDef = &ContextCU->createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, nullptr);
ContextCU->applySubprogramAttributesToDefinition(SP, *AbsDef);
if (!ContextCU->includeMinimalInlineScopes())
ContextCU->addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
if (DIE *ObjectPointer = ContextCU->createAndAddScopeChildren(Scope, *AbsDef))
ContextCU->addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
}
/// Whether to use the GNU analog for a DWARF5 tag, attribute, or location atom.
static bool useGNUAnalogForDwarf5Feature(DwarfDebug *DD) {
return DD->getDwarfVersion() == 4 && DD->tuneForGDB();
}
dwarf::Tag DwarfCompileUnit::getDwarf5OrGNUTag(dwarf::Tag Tag) const {
if (!useGNUAnalogForDwarf5Feature(DD))
return Tag;
switch (Tag) {
case dwarf::DW_TAG_call_site:
return dwarf::DW_TAG_GNU_call_site;
case dwarf::DW_TAG_call_site_parameter:
return dwarf::DW_TAG_GNU_call_site_parameter;
default:
llvm_unreachable("DWARF5 tag with no GNU analog");
}
}
dwarf::Attribute
DwarfCompileUnit::getDwarf5OrGNUAttr(dwarf::Attribute Attr) const {
if (!useGNUAnalogForDwarf5Feature(DD))
return Attr;
switch (Attr) {
case dwarf::DW_AT_call_all_calls:
return dwarf::DW_AT_GNU_all_call_sites;
case dwarf::DW_AT_call_target:
return dwarf::DW_AT_GNU_call_site_target;
case dwarf::DW_AT_call_origin:
return dwarf::DW_AT_abstract_origin;
case dwarf::DW_AT_call_return_pc:
return dwarf::DW_AT_low_pc;
case dwarf::DW_AT_call_value:
return dwarf::DW_AT_GNU_call_site_value;
case dwarf::DW_AT_call_tail_call:
return dwarf::DW_AT_GNU_tail_call;
default:
llvm_unreachable("DWARF5 attribute with no GNU analog");
}
}
dwarf::LocationAtom
DwarfCompileUnit::getDwarf5OrGNULocationAtom(dwarf::LocationAtom Loc) const {
if (!useGNUAnalogForDwarf5Feature(DD))
return Loc;
switch (Loc) {
case dwarf::DW_OP_entry_value:
return dwarf::DW_OP_GNU_entry_value;
default:
llvm_unreachable("DWARF5 location atom with no GNU analog");
}
}
DIE &DwarfCompileUnit::constructCallSiteEntryDIE(DIE &ScopeDIE,
DIE *CalleeDIE,
bool IsTail,
const MCSymbol *PCAddr,
unsigned CallReg) {
// Insert a call site entry DIE within ScopeDIE.
DIE &CallSiteDIE = createAndAddDIE(getDwarf5OrGNUTag(dwarf::DW_TAG_call_site),
ScopeDIE, nullptr);
if (CallReg) {
// Indirect call.
addAddress(CallSiteDIE, getDwarf5OrGNUAttr(dwarf::DW_AT_call_target),
MachineLocation(CallReg));
} else {
assert(CalleeDIE && "No DIE for call site entry origin");
addDIEEntry(CallSiteDIE, getDwarf5OrGNUAttr(dwarf::DW_AT_call_origin),
*CalleeDIE);
}
if (IsTail)
// Attach DW_AT_call_tail_call to tail calls for standards compliance.
addFlag(CallSiteDIE, getDwarf5OrGNUAttr(dwarf::DW_AT_call_tail_call));
// Attach the return PC to allow the debugger to disambiguate call paths
// from one function to another.
//
// The return PC is only really needed when the call /isn't/ a tail call, but
// for some reason GDB always expects it.
if (!IsTail || DD->tuneForGDB()) {
assert(PCAddr && "Missing return PC information for a call");
addLabelAddress(CallSiteDIE,
getDwarf5OrGNUAttr(dwarf::DW_AT_call_return_pc), PCAddr);
}
return CallSiteDIE;
}
void DwarfCompileUnit::constructCallSiteParmEntryDIEs(
DIE &CallSiteDIE, SmallVector<DbgCallSiteParam, 4> &Params) {
for (const auto &Param : Params) {
unsigned Register = Param.getRegister();
auto CallSiteDieParam =
DIE::get(DIEValueAllocator,
getDwarf5OrGNUTag(dwarf::DW_TAG_call_site_parameter));
insertDIE(CallSiteDieParam);
addAddress(*CallSiteDieParam, dwarf::DW_AT_location,
MachineLocation(Register));
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
DwarfExpr.setCallSiteParamValueFlag();
DwarfDebug::emitDebugLocValue(*Asm, nullptr, Param.getValue(), DwarfExpr);
addBlock(*CallSiteDieParam, getDwarf5OrGNUAttr(dwarf::DW_AT_call_value),
DwarfExpr.finalize());
CallSiteDIE.addChild(CallSiteDieParam);
}
}
DIE *DwarfCompileUnit::constructImportedEntityDIE(
const DIImportedEntity *Module) {
DIE *IMDie = DIE::get(DIEValueAllocator, (dwarf::Tag)Module->getTag());
insertDIE(Module, IMDie);
DIE *EntityDie;
auto *Entity = Module->getEntity();
if (auto *NS = dyn_cast<DINamespace>(Entity))
EntityDie = getOrCreateNameSpace(NS);
else if (auto *M = dyn_cast<DIModule>(Entity))
EntityDie = getOrCreateModule(M);
else if (auto *SP = dyn_cast<DISubprogram>(Entity))
EntityDie = getOrCreateSubprogramDIE(SP);
else if (auto *T = dyn_cast<DIType>(Entity))
EntityDie = getOrCreateTypeDIE(T);
else if (auto *GV = dyn_cast<DIGlobalVariable>(Entity))
EntityDie = getOrCreateGlobalVariableDIE(GV, {});
else
EntityDie = getDIE(Entity);
assert(EntityDie);
addSourceLine(*IMDie, Module->getLine(), Module->getFile());
addDIEEntry(*IMDie, dwarf::DW_AT_import, *EntityDie);
StringRef Name = Module->getName();
if (!Name.empty())
addString(*IMDie, dwarf::DW_AT_name, Name);
return IMDie;
}
void DwarfCompileUnit::finishSubprogramDefinition(const DISubprogram *SP) {
DIE *D = getDIE(SP);
if (DIE *AbsSPDIE = getAbstractSPDies().lookup(SP)) {
if (D)
// If this subprogram has an abstract definition, reference that
addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
} else {
assert(D || includeMinimalInlineScopes());
if (D)
// And attach the attributes
applySubprogramAttributesToDefinition(SP, *D);
}
}
void DwarfCompileUnit::finishEntityDefinition(const DbgEntity *Entity) {
DbgEntity *AbsEntity = getExistingAbstractEntity(Entity->getEntity());
auto *Die = Entity->getDIE();
/// Label may be used to generate DW_AT_low_pc, so put it outside
/// if/else block.
const DbgLabel *Label = nullptr;
if (AbsEntity && AbsEntity->getDIE()) {
addDIEEntry(*Die, dwarf::DW_AT_abstract_origin, *AbsEntity->getDIE());
Label = dyn_cast<const DbgLabel>(Entity);
} else {
if (const DbgVariable *Var = dyn_cast<const DbgVariable>(Entity))
applyVariableAttributes(*Var, *Die);
else if ((Label = dyn_cast<const DbgLabel>(Entity)))
applyLabelAttributes(*Label, *Die);
else
llvm_unreachable("DbgEntity must be DbgVariable or DbgLabel.");
}
if (Label)
if (const auto *Sym = Label->getSymbol())
addLabelAddress(*Die, dwarf::DW_AT_low_pc, Sym);
}
DbgEntity *DwarfCompileUnit::getExistingAbstractEntity(const DINode *Node) {
auto &AbstractEntities = getAbstractEntities();
auto I = AbstractEntities.find(Node);
if (I != AbstractEntities.end())
return I->second.get();
return nullptr;
}
void DwarfCompileUnit::createAbstractEntity(const DINode *Node,
LexicalScope *Scope) {
assert(Scope && Scope->isAbstractScope());
auto &Entity = getAbstractEntities()[Node];
if (isa<const DILocalVariable>(Node)) {
Entity = std::make_unique<DbgVariable>(
cast<const DILocalVariable>(Node), nullptr /* IA */);;
DU->addScopeVariable(Scope, cast<DbgVariable>(Entity.get()));
} else if (isa<const DILabel>(Node)) {
Entity = std::make_unique<DbgLabel>(
cast<const DILabel>(Node), nullptr /* IA */);
DU->addScopeLabel(Scope, cast<DbgLabel>(Entity.get()));
}
}
void DwarfCompileUnit::emitHeader(bool UseOffsets) {
// Don't bother labeling the .dwo unit, as its offset isn't used.
if (!Skeleton && !DD->useSectionsAsReferences()) {
LabelBegin = Asm->createTempSymbol("cu_begin");
Asm->OutStreamer->EmitLabel(LabelBegin);
}
dwarf::UnitType UT = Skeleton ? dwarf::DW_UT_split_compile
: DD->useSplitDwarf() ? dwarf::DW_UT_skeleton
: dwarf::DW_UT_compile;
DwarfUnit::emitCommonHeader(UseOffsets, UT);
if (DD->getDwarfVersion() >= 5 && UT != dwarf::DW_UT_compile)
Asm->emitInt64(getDWOId());
}
bool DwarfCompileUnit::hasDwarfPubSections() const {
switch (CUNode->getNameTableKind()) {
case DICompileUnit::DebugNameTableKind::None:
return false;
// Opting in to GNU Pubnames/types overrides the default to ensure these are
// generated for things like Gold's gdb_index generation.
case DICompileUnit::DebugNameTableKind::GNU:
return true;
case DICompileUnit::DebugNameTableKind::Default:
return DD->tuneForGDB() && !includeMinimalInlineScopes() &&
!CUNode->isDebugDirectivesOnly() &&
DD->getAccelTableKind() != AccelTableKind::Apple &&
DD->getDwarfVersion() < 5;
}
llvm_unreachable("Unhandled DICompileUnit::DebugNameTableKind enum");
}
/// addGlobalName - Add a new global name to the compile unit.
void DwarfCompileUnit::addGlobalName(StringRef Name, const DIE &Die,
const DIScope *Context) {
if (!hasDwarfPubSections())
return;
std::string FullName = getParentContextString(Context) + Name.str();
GlobalNames[FullName] = &Die;
}
void DwarfCompileUnit::addGlobalNameForTypeUnit(StringRef Name,
const DIScope *Context) {
if (!hasDwarfPubSections())
return;
std::string FullName = getParentContextString(Context) + Name.str();
// Insert, allowing the entry to remain as-is if it's already present
// This way the CU-level type DIE is preferred over the "can't describe this
// type as a unit offset because it's not really in the CU at all, it's only
// in a type unit"
GlobalNames.insert(std::make_pair(std::move(FullName), &getUnitDie()));
}
/// Add a new global type to the unit.
void DwarfCompileUnit::addGlobalType(const DIType *Ty, const DIE &Die,
const DIScope *Context) {
if (!hasDwarfPubSections())
return;
std::string FullName = getParentContextString(Context) + Ty->getName().str();
GlobalTypes[FullName] = &Die;
}
void DwarfCompileUnit::addGlobalTypeUnitType(const DIType *Ty,
const DIScope *Context) {
if (!hasDwarfPubSections())
return;
std::string FullName = getParentContextString(Context) + Ty->getName().str();
// Insert, allowing the entry to remain as-is if it's already present
// This way the CU-level type DIE is preferred over the "can't describe this
// type as a unit offset because it's not really in the CU at all, it's only
// in a type unit"
GlobalTypes.insert(std::make_pair(std::move(FullName), &getUnitDie()));
}
void DwarfCompileUnit::addVariableAddress(const DbgVariable &DV, DIE &Die,
MachineLocation Location) {
if (DV.hasComplexAddress())
addComplexAddress(DV, Die, dwarf::DW_AT_location, Location);
else
addAddress(Die, dwarf::DW_AT_location, Location);
}
/// Add an address attribute to a die based on the location provided.
void DwarfCompileUnit::addAddress(DIE &Die, dwarf::Attribute Attribute,
const MachineLocation &Location) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
if (Location.isIndirect())
DwarfExpr.setMemoryLocationKind();
DIExpressionCursor Cursor({});
const TargetRegisterInfo &TRI = *Asm->MF->getSubtarget().getRegisterInfo();
if (!DwarfExpr.addMachineRegExpression(TRI, Cursor, Location.getReg()))
return;
DwarfExpr.addExpression(std::move(Cursor));
// Now attach the location information to the DIE.
addBlock(Die, Attribute, DwarfExpr.finalize());
if (DwarfExpr.TagOffset)
addUInt(Die, dwarf::DW_AT_LLVM_tag_offset, dwarf::DW_FORM_data1,
*DwarfExpr.TagOffset);
}
/// Start with the address based on the location provided, and generate the
/// DWARF information necessary to find the actual variable given the extra
/// address information encoded in the DbgVariable, starting from the starting
/// location. Add the DWARF information to the die.
void DwarfCompileUnit::addComplexAddress(const DbgVariable &DV, DIE &Die,
dwarf::Attribute Attribute,
const MachineLocation &Location) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
const DIExpression *DIExpr = DV.getSingleExpression();
DwarfExpr.addFragmentOffset(DIExpr);
if (Location.isIndirect())
DwarfExpr.setMemoryLocationKind();
DIExpressionCursor Cursor(DIExpr);
if (DIExpr->isEntryValue()) {
DwarfExpr.setEntryValueFlag();
DwarfExpr.beginEntryValueExpression(Cursor);
}
const TargetRegisterInfo &TRI = *Asm->MF->getSubtarget().getRegisterInfo();
if (!DwarfExpr.addMachineRegExpression(TRI, Cursor, Location.getReg()))
return;
DwarfExpr.addExpression(std::move(Cursor));
// Now attach the location information to the DIE.
addBlock(Die, Attribute, DwarfExpr.finalize());
if (DwarfExpr.TagOffset)
addUInt(Die, dwarf::DW_AT_LLVM_tag_offset, dwarf::DW_FORM_data1,
*DwarfExpr.TagOffset);
}
/// Add a Dwarf loclistptr attribute data and value.
void DwarfCompileUnit::addLocationList(DIE &Die, dwarf::Attribute Attribute,
unsigned Index) {
dwarf::Form Form = dwarf::DW_FORM_data4;
if (DD->getDwarfVersion() == 4)
Form =dwarf::DW_FORM_sec_offset;
if (DD->getDwarfVersion() >= 5)
Form =dwarf::DW_FORM_loclistx;
Die.addValue(DIEValueAllocator, Attribute, Form, DIELocList(Index));
}
void DwarfCompileUnit::applyVariableAttributes(const DbgVariable &Var,
DIE &VariableDie) {
StringRef Name = Var.getName();
if (!Name.empty())
addString(VariableDie, dwarf::DW_AT_name, Name);
const auto *DIVar = Var.getVariable();
if (DIVar)
if (uint32_t AlignInBytes = DIVar->getAlignInBytes())
addUInt(VariableDie, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
AlignInBytes);
addSourceLine(VariableDie, DIVar);
addType(VariableDie, Var.getType());
if (Var.isArtificial())
addFlag(VariableDie, dwarf::DW_AT_artificial);
}
void DwarfCompileUnit::applyLabelAttributes(const DbgLabel &Label,
DIE &LabelDie) {
StringRef Name = Label.getName();
if (!Name.empty())
addString(LabelDie, dwarf::DW_AT_name, Name);
const auto *DILabel = Label.getLabel();
addSourceLine(LabelDie, DILabel);
}
/// Add a Dwarf expression attribute data and value.
void DwarfCompileUnit::addExpr(DIELoc &Die, dwarf::Form Form,
const MCExpr *Expr) {
Die.addValue(DIEValueAllocator, (dwarf::Attribute)0, Form, DIEExpr(Expr));
}
void DwarfCompileUnit::applySubprogramAttributesToDefinition(
const DISubprogram *SP, DIE &SPDie) {
auto *SPDecl = SP->getDeclaration();
auto *Context = SPDecl ? SPDecl->getScope() : SP->getScope();
applySubprogramAttributes(SP, SPDie, includeMinimalInlineScopes());
addGlobalName(SP->getName(), SPDie, Context);
}
bool DwarfCompileUnit::isDwoUnit() const {
return DD->useSplitDwarf() && Skeleton;
}
void DwarfCompileUnit::finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) {
constructTypeDIE(D, CTy);
}
bool DwarfCompileUnit::includeMinimalInlineScopes() const {
return getCUNode()->getEmissionKind() == DICompileUnit::LineTablesOnly ||
(DD->useSplitDwarf() && !Skeleton);
}
void DwarfCompileUnit::addAddrTableBase() {
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
MCSymbol *Label = DD->getAddressPool().getLabel();
addSectionLabel(getUnitDie(),
getDwarfVersion() >= 5 ? dwarf::DW_AT_addr_base
: dwarf::DW_AT_GNU_addr_base,
Label, TLOF.getDwarfAddrSection()->getBeginSymbol());
}
void DwarfCompileUnit::addBaseTypeRef(DIEValueList &Die, int64_t Idx) {
Die.addValue(DIEValueAllocator, (dwarf::Attribute)0, dwarf::DW_FORM_udata,
new (DIEValueAllocator) DIEBaseTypeRef(this, Idx));
}
void DwarfCompileUnit::createBaseTypeDIEs() {
// Insert the base_type DIEs directly after the CU so that their offsets will
// fit in the fixed size ULEB128 used inside the location expressions.
// Maintain order by iterating backwards and inserting to the front of CU
// child list.
for (auto &Btr : reverse(ExprRefedBaseTypes)) {
DIE &Die = getUnitDie().addChildFront(
DIE::get(DIEValueAllocator, dwarf::DW_TAG_base_type));
SmallString<32> Str;
addString(Die, dwarf::DW_AT_name,
Twine(dwarf::AttributeEncodingString(Btr.Encoding) +
"_" + Twine(Btr.BitSize)).toStringRef(Str));
addUInt(Die, dwarf::DW_AT_encoding, dwarf::DW_FORM_data1, Btr.Encoding);
addUInt(Die, dwarf::DW_AT_byte_size, None, Btr.BitSize / 8);
Btr.Die = &Die;
}
}
Reference in New Issue View Git Blame Copy Permalink