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llvm-project/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
Vladislav Dzhidzhoev b9cecee3fb Reland "[DebugMetadata][DwarfDebug] Support function-local types in lexical block scopes (4/7)" (#165032) 
This is an attempt to merge https://reviews.llvm.org/D144006 with LTO
fix.

The last merge attempt was
https://github.com/llvm/llvm-project/pull/75385.
The issue with it was investigated in
https://github.com/llvm/llvm-project/pull/75385#issuecomment-2386684121.
The problem happens when 
1. Several modules are being linked.
2. There are several DISubprograms that initially belong to different
modules but represent the same source code function (for example, a
function included from the same source code file).
3. Some of such DISubprograms survive IR linking. It may happen if one
of them is inlined somewhere or if the functions that have these
DISubprograms attached have internal linkage.
4. Each of these DISubprograms has a local type that corresponds to the
same source code type. These types are initially from different modules,
but have the same ODR identifier.

If the same (in the sense of ODR identifier/ODR uniquing rules) local
type is present in two modules, and these modules are linked together,
the type gets uniqued. A DIType, that happens to be loaded first,
survives linking, and the references on other types with the same ODR
identifier from the modules loaded later are replaced with the
references on the DIType loaded first. Since defintion subprograms, in
scope of which these types are located, are not deduplicated, the linker
output may contain multiple DISubprogram's having the same (uniqued)
type in their retainedNodes lists.
Further compilation of such modules causes crashes.

To tackle that,
* previous solution to handle LTO linking with local types in
retainedNodes is removed (cloneLocalTypes() function),
* for each loaded distinct (definition) DISubprogram, its retainedNodes
list is scanned after loading, and DITypes with a scope of another
subprogram are removed. If something from a Function corresponding to
the DISubprogram references uniqued type, we rely on cross-CU links.

Additionally:
* a check is added to Verifier to report about local types located in a
wrong retainedNodes list,

Original commit message follows.
---------

RFC https://discourse.llvm.org/t/rfc-dwarfdebug-fix-and-improve-handling-imported-entities-types-and-static-local-in-subprogram-and-lexical-block-scopes/68544

Similar to imported declarations, the patch tracks function-local types in
DISubprogram's 'retainedNodes' field. DwarfDebug is adjusted in accordance with
the aforementioned metadata change and provided a support of function-local
types scoped within a lexical block.

The patch assumes that DICompileUnit's 'enums field' no longer tracks local
types and DwarfDebug would assert if any locally-scoped types get placed there.

Authored-by: Kristina Bessonova <kbessonova@accesssoftek.com>
Co-authored-by: Jeremy Morse <jeremy.morse@sony.com>
2026-02-04 00:34:52 +01:00

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//===- 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 "DwarfExpression.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/DIE.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.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/GlobalVariable.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolWasm.h"
#include "llvm/MC/MachineLocation.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/NVPTXAddrSpace.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <optional>
#include <string>
#include <utility>
using namespace llvm;
/// Query value using AddLinkageNamesToDeclCallOriginsForTuning.
static cl::opt<cl::boolOrDefault> AddLinkageNamesToDeclCallOrigins(
"add-linkage-names-to-declaration-call-origins", cl::Hidden,
cl::desc("Add DW_AT_linkage_name to function declaration DIEs "
"referenced by DW_AT_call_origin attributes. Enabled by default "
"for -gsce debugger tuning."));
static cl::opt<bool> EmitFuncLineTableOffsetsOption(
"emit-func-debug-line-table-offsets", cl::Hidden,
cl::desc("Include line table offset in function's debug info and emit end "
"sequence after each function's line data."),
cl::init(false));
static bool AddLinkageNamesToDeclCallOriginsForTuning(const DwarfDebug *DD) {
bool EnabledByDefault = DD->tuneForSCE();
if (EnabledByDefault)
return AddLinkageNamesToDeclCallOrigins != cl::boolOrDefault::BOU_FALSE;
return AddLinkageNamesToDeclCallOrigins == cl::boolOrDefault::BOU_TRUE;
}
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;
}
/// Translate NVVM IR address space code to DWARF correspondent value
static unsigned translateToNVVMDWARFAddrSpace(unsigned AddrSpace) {
switch (AddrSpace) {
case NVPTXAS::ADDRESS_SPACE_GENERIC:
return NVPTXAS::DWARF_ADDR_generic_space;
case NVPTXAS::ADDRESS_SPACE_GLOBAL:
return NVPTXAS::DWARF_ADDR_global_space;
case NVPTXAS::ADDRESS_SPACE_SHARED:
return NVPTXAS::DWARF_ADDR_shared_space;
case NVPTXAS::ADDRESS_SPACE_CONST:
return NVPTXAS::DWARF_ADDR_const_space;
case NVPTXAS::ADDRESS_SPACE_LOCAL:
return NVPTXAS::DWARF_ADDR_local_space;
default:
llvm_unreachable(
"Cannot translate unknown address space to DWARF address space");
return AddrSpace;
}
}
DwarfCompileUnit::DwarfCompileUnit(unsigned UID, const DICompileUnit *Node,
AsmPrinter *A, DwarfDebug *DW,
DwarfFile *DWU, UnitKind Kind)
: DwarfUnit(GetCompileUnitType(Kind, DW), Node, A, DW, DWU, 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) {
if ((Skeleton || !DD->useSplitDwarf()) && Label)
DD->addArangeLabel(SymbolCU(this, 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);
bool UseAddrOffsetFormOrExpressions =
DD->useAddrOffsetForm() || DD->useAddrOffsetExpressions();
const MCSymbol *Base = nullptr;
if (Label->isInSection() && UseAddrOffsetFormOrExpressions)
Base = DD->getSectionLabel(&Label->getSection());
if (!Base || Base == Label) {
unsigned idx = DD->getAddressPool().getIndex(Label);
addAttribute(Die, Attribute,
DD->getDwarfVersion() >= 5 ? dwarf::DW_FORM_addrx
: dwarf::DW_FORM_GNU_addr_index,
DIEInteger(idx));
return;
}
// Could be extended to work with DWARFv4 Split DWARF if that's important for
// someone. In that case DW_FORM_data would be used.
assert(DD->getDwarfVersion() >= 5 &&
"Addr+offset expressions are only valuable when using debug_addr (to "
"reduce relocations) available in DWARFv5 or higher");
if (DD->useAddrOffsetExpressions()) {
auto *Loc = new (DIEValueAllocator) DIEBlock();
addPoolOpAddress(*Loc, Label);
addBlock(Die, Attribute, dwarf::DW_FORM_exprloc, Loc);
} else
addAttribute(Die, Attribute, dwarf::DW_FORM_LLVM_addrx_offset,
new (DIEValueAllocator) DIEAddrOffset(
DD->getAddressPool().getIndex(Base), Label, Base));
}
void DwarfCompileUnit::addLocalLabelAddress(DIE &Die,
dwarf::Attribute Attribute,
const MCSymbol *Label) {
if (Label)
addAttribute(Die, Attribute, dwarf::DW_FORM_addr, DIELabel(Label));
else
addAttribute(Die, 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, "", "", std::nullopt,
std::nullopt, CUID);
if (LastFile != File) {
LastFile = File;
LastFileID = Asm->OutStreamer->emitDwarfFileDirective(
0, File->getDirectory(), File->getFilename(), DD->getMD5AsBytes(File),
File->getSource(), CUID);
}
return LastFileID;
}
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();
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.
StringRef DisplayName = GV->getDisplayName();
if (!DisplayName.empty())
addString(*VariableDIE, dwarf::DW_AT_name, GV->getDisplayName());
if (GTy)
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);
addAnnotation(*VariableDIE, GV->getAnnotations());
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;
std::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) or
// DW_AT_location(DW_OP_consts, X, DW_OP_stack_value) becomes
// DW_AT_const_value(X).
if (GlobalExprs.size() == 1 && Expr && Expr->isConstant()) {
addToAccelTable = true;
addConstantValue(
*VariableDIE,
DIExpression::SignedOrUnsignedConstant::UnsignedConstant ==
*Expr->isConstant(),
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) {
// cuda-gdb special requirement. See NVPTXAS::DWARF_AddressSpace
// Decode DW_OP_constu <DWARF Address Space> DW_OP_swap DW_OP_xderef
// sequence to specify corresponding address space.
if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB()) {
unsigned LocalNVPTXAddressSpace;
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);
// 16-bit platforms like MSP430 and AVR take this path, so sink this
// assert to platforms that use it.
auto GetPointerSizedFormAndOp = [this]() {
unsigned PointerSize = Asm->MAI->getCodePointerSize();
assert((PointerSize == 4 || PointerSize == 8) &&
"Add support for other sizes if necessary");
struct FormAndOp {
dwarf::Form Form;
dwarf::LocationAtom Op;
};
return PointerSize == 4
? FormAndOp{dwarf::DW_FORM_data4, dwarf::DW_OP_const4u}
: FormAndOp{dwarf::DW_FORM_data8, dwarf::DW_OP_const8u};
};
if (Global->isThreadLocal()) {
if (Asm->TM.getTargetTriple().isWasm()) {
// FIXME This is not guaranteed, but in practice, in static linking,
// if present, __tls_base's index is 1. This doesn't hold for dynamic
// linking, so TLS variables used in dynamic linking won't have
// correct debug info for now. See
// https://github.com/llvm/llvm-project/blob/19afbfe33156d211fa959dadeea46cd17b9c723c/lld/wasm/Driver.cpp#L786-L823
addWasmRelocBaseGlobal(Loc, "__tls_base", 1);
addOpAddress(*Loc, Sym);
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
} else if (Asm->TM.useEmulatedTLS()) {
// TODO: add debug info for emulated thread local mode.
} else {
// FIXME: Make this work with -gsplit-dwarf.
// Based on GCC's support for TLS:
if (!DD->useSplitDwarf()) {
auto FormAndOp = GetPointerSizedFormAndOp();
// 1) Start with a constNu of the appropriate pointer size
addUInt(*Loc, dwarf::DW_FORM_data1, FormAndOp.Op);
// 2) containing the (relocated) offset of the TLS variable
// within the module's TLS block.
addExpr(*Loc, FormAndOp.Form,
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 if (Asm->TM.getTargetTriple().isWasm() &&
Asm->TM.getRelocationModel() == Reloc::PIC_) {
// FIXME This is not guaranteed, but in practice, if present,
// __memory_base's index is 1. See
// https://github.com/llvm/llvm-project/blob/19afbfe33156d211fa959dadeea46cd17b9c723c/lld/wasm/Driver.cpp#L786-L823
addWasmRelocBaseGlobal(Loc, "__memory_base", 1);
addOpAddress(*Loc, Sym);
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
} else if ((Asm->TM.getRelocationModel() == Reloc::RWPI ||
Asm->TM.getRelocationModel() == Reloc::ROPI_RWPI) &&
!Asm->getObjFileLowering()
.getKindForGlobal(Global, Asm->TM)
.isReadOnly()) {
auto FormAndOp = GetPointerSizedFormAndOp();
// Constant
addUInt(*Loc, dwarf::DW_FORM_data1, FormAndOp.Op);
// Relocation offset
addExpr(*Loc, FormAndOp.Form,
Asm->getObjFileLowering().getIndirectSymViaRWPI(Sym));
// Base register
Register BaseReg = Asm->getObjFileLowering().getStaticBase();
unsigned DwarfBaseReg =
Asm->TM.getMCRegisterInfo()->getDwarfRegNum(BaseReg, false);
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_breg0 + DwarfBaseReg);
// Offset from base register
addSInt(*Loc, dwarf::DW_FORM_sdata, 0);
// Operation
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
} else {
DD->addArangeLabel(SymbolCU(this, Sym));
addOpAddress(*Loc, Sym);
}
if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB() &&
!NVPTXAddressSpace)
NVPTXAddressSpace =
translateToNVVMDWARFAddrSpace(Global->getType()->getAddressSpace());
}
// 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()) {
// cuda-gdb special requirement. See NVPTXAS::DWARF_AddressSpace
addUInt(*VariableDIE, dwarf::DW_AT_address_class, dwarf::DW_FORM_data1,
NVPTXAddressSpace.value_or(NVPTXAS::DWARF_ADDR_global_space));
}
if (Loc)
addBlock(*VariableDIE, dwarf::DW_AT_location, DwarfExpr->finalize());
if (DD->useAllLinkageNames())
addLinkageName(*VariableDIE, GV->getLinkageName());
if (addToAccelTable) {
DD->addAccelName(*this, CUNode->getNameTableKind(), 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(*this, CUNode->getNameTableKind(), GV->getLinkageName(),
*VariableDIE);
}
}
DIE *DwarfCompileUnit::getOrCreateCommonBlock(
const DICommonBlock *CB, ArrayRef<GlobalExpr> GlobalExprs) {
// Check for pre-existence.
if (DIE *NDie = getDIE(CB))
return NDie;
DIE *ContextDIE = getOrCreateContextDIE(CB->getScope());
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(), /*Column*/ 0, CB->getFile());
if (DIGlobalVariable *V = CB->getDecl())
getCU().addLocationAttribute(&NDie, V, GlobalExprs);
return &NDie;
}
void DwarfCompileUnit::addRange(RangeSpan Range) {
DD->insertSectionLabel(Range.Begin);
auto *PrevCU = DD->getPrevCU();
bool SameAsPrevCU = this == PrevCU;
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())) {
// Before a new range is added, always terminate the prior line table.
if (PrevCU)
DD->terminateLineTable(PrevCU);
CURanges.push_back(Range);
return;
}
CURanges.back().End = Range.End;
}
void DwarfCompileUnit::initStmtList() {
if (CUNode->isDebugDirectivesOnly())
return;
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.
addSectionLabel(getUnitDie(), dwarf::DW_AT_stmt_list, LineTableStartSym,
TLOF.getDwarfLineSection()->getBeginSymbol());
}
void DwarfCompileUnit::applyStmtList(DIE &D) {
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
addSectionLabel(D, dwarf::DW_AT_stmt_list, LineTableStartSym,
TLOF.getDwarfLineSection()->getBeginSymbol());
}
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 &&
(!isDwoUnit() || !llvm::isRangeRelaxable(Begin, End))) {
addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
return;
}
addLabelAddress(D, dwarf::DW_AT_high_pc, End);
}
// Add info for Wasm-global-based relocation.
// 'GlobalIndex' is used for split dwarf, which currently relies on a few
// assumptions that are not guaranteed in a formal way but work in practice.
void DwarfCompileUnit::addWasmRelocBaseGlobal(DIELoc *Loc, StringRef GlobalName,
uint64_t GlobalIndex) {
// FIXME: duplicated from Target/WebAssembly/WebAssembly.h
// don't want to depend on target specific headers in this code?
const unsigned TI_GLOBAL_RELOC = 3;
unsigned PointerSize = Asm->getDataLayout().getPointerSize();
auto *Sym =
static_cast<MCSymbolWasm *>(Asm->GetExternalSymbolSymbol(GlobalName));
// FIXME: this repeats what WebAssemblyMCInstLower::
// GetExternalSymbolSymbol does, since if there's no code that
// refers to this symbol, we have to set it here.
Sym->setType(wasm::WASM_SYMBOL_TYPE_GLOBAL);
Sym->setGlobalType(wasm::WasmGlobalType{
static_cast<uint8_t>(PointerSize == 4 ? wasm::WASM_TYPE_I32
: wasm::WASM_TYPE_I64),
true});
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_WASM_location);
addSInt(*Loc, dwarf::DW_FORM_sdata, TI_GLOBAL_RELOC);
if (!isDwoUnit()) {
addLabel(*Loc, dwarf::DW_FORM_data4, Sym);
} else {
// FIXME: when writing dwo, we need to avoid relocations. Probably
// the "right" solution is to treat globals the way func and data
// symbols are (with entries in .debug_addr).
// For now we hardcode the indices in the callsites. Global indices are not
// fixed, but in practice a few are fixed; for example, __stack_pointer is
// always index 0.
addUInt(*Loc, dwarf::DW_FORM_data4, GlobalIndex);
}
}
// 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,
const Function &F,
MCSymbol *LineTableSym) {
DIE *SPDie = getOrCreateSubprogramDIE(SP, &F, includeMinimalInlineScopes());
SmallVector<RangeSpan, 2> BB_List;
// If basic block sections are on, ranges for each basic block section has
// to be emitted separately.
for (const auto &R : Asm->MBBSectionRanges)
BB_List.push_back({R.second.BeginLabel, R.second.EndLabel});
attachRangesOrLowHighPC(*SPDie, BB_List);
if (DD->useAppleExtensionAttributes() &&
!DD->getCurrentFunction()->getTarget().Options.DisableFramePointerElim(
*DD->getCurrentFunction()))
addFlag(*SPDie, dwarf::DW_AT_APPLE_omit_frame_ptr);
if (emitFuncLineTableOffsets() && LineTableSym) {
addSectionLabel(
*SPDie, dwarf::DW_AT_LLVM_stmt_sequence, LineTableSym,
Asm->getObjFileLowering().getDwarfLineSection()->getBeginSymbol());
}
// 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);
if (FrameBase.Location.Offset != 0) {
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_consts);
addSInt(*Loc, dwarf::DW_FORM_sdata, FrameBase.Location.Offset);
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
}
addBlock(*SPDie, dwarf::DW_AT_frame_base, Loc);
break;
}
case TargetFrameLowering::DwarfFrameBase::WasmFrameBase: {
// FIXME: duplicated from Target/WebAssembly/WebAssembly.h
const unsigned TI_GLOBAL_RELOC = 3;
if (FrameBase.Location.WasmLoc.Kind == TI_GLOBAL_RELOC) {
// These need to be relocatable.
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
assert(FrameBase.Location.WasmLoc.Index == 0); // Only SP so far.
// For now, since we only ever use index 0, this should work as-is.
addWasmRelocBaseGlobal(Loc, "__stack_pointer",
FrameBase.Location.WasmLoc.Index);
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_stack_value);
addBlock(*SPDie, dwarf::DW_AT_frame_base, Loc);
} else {
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(*this, CUNode->getNameTableKind(), SP, *SPDie);
return *SPDie;
}
// Construct a DIE for this scope.
void DwarfCompileUnit::constructScopeDIE(LexicalScope *Scope,
DIE &ParentScopeDIE) {
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");
// Emit inlined subprograms.
if (Scope->getParent() && isa<DISubprogram>(DS)) {
DIE *ScopeDIE = constructInlinedScopeDIE(Scope, ParentScopeDIE);
assert(ScopeDIE && "Scope DIE should not be null.");
createAndAddScopeChildren(Scope, *ScopeDIE);
return;
}
// Early exit when we know the scope DIE is going to be null.
if (DD->isLexicalScopeDIENull(Scope))
return;
// Emit lexical blocks.
DIE *ScopeDIE = getOrCreateLexicalBlockDIE(Scope, ParentScopeDIE);
assert(ScopeDIE && "Scope DIE should not be null.");
createAndAddScopeChildren(Scope, *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) {
assert(!Ranges.empty());
if (!DD->useRangesSection() ||
(Ranges.size() == 1 &&
(!DD->alwaysUseRanges(*this) ||
DD->getSectionLabel(&Ranges.front().Begin->getSection()) ==
Ranges.front().Begin))) {
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) {
auto *BeginLabel = DD->getLabelBeforeInsn(R.first);
auto *EndLabel = DD->getLabelAfterInsn(R.second);
const auto *BeginMBB = R.first->getParent();
const auto *EndMBB = R.second->getParent();
const auto *MBB = BeginMBB;
// Basic block sections allows basic block subsets to be placed in unique
// sections. For each section, the begin and end label must be added to the
// list. If there is more than one range, debug ranges must be used.
// Otherwise, low/high PC can be used.
// FIXME: Debug Info Emission depends on block order and this assumes that
// the order of blocks will be frozen beyond this point.
do {
if (MBB->sameSection(EndMBB) || MBB->isEndSection()) {
auto MBBSectionRange = Asm->MBBSectionRanges[MBB->getSectionID()];
List.push_back(
{MBB->sameSection(BeginMBB) ? BeginLabel
: MBBSectionRange.BeginLabel,
MBB->sameSection(EndMBB) ? EndLabel : MBBSectionRange.EndLabel});
}
if (MBB->sameSection(EndMBB))
break;
MBB = MBB->getNextNode();
} while (true);
}
attachRangesOrLowHighPC(Die, std::move(List));
}
DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope,
DIE &ParentScopeDIE) {
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 = getAbstractScopeDIEs()[InlinedSP];
assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_inlined_subroutine);
ParentScopeDIE.addChild(ScopeDIE);
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, std::nullopt,
getOrCreateSourceID(IA->getFile()));
addUInt(*ScopeDIE, dwarf::DW_AT_call_line, std::nullopt, IA->getLine());
if (IA->getColumn())
addUInt(*ScopeDIE, dwarf::DW_AT_call_column, std::nullopt, IA->getColumn());
if (IA->getDiscriminator() && DD->getDwarfVersion() >= 4)
addUInt(*ScopeDIE, dwarf::DW_AT_GNU_discriminator, std::nullopt,
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(*this, CUNode->getNameTableKind(), InlinedSP,
*ScopeDIE);
return ScopeDIE;
}
DIE *DwarfCompileUnit::getOrCreateLexicalBlockDIE(LexicalScope *Scope,
DIE &ParentScopeDIE) {
if (DD->isLexicalScopeDIENull(Scope))
return nullptr;
const auto *DS = Scope->getScopeNode();
auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_lexical_block);
ParentScopeDIE.addChild(ScopeDIE);
if (Scope->isAbstractScope()) {
assert(!getAbstractScopeDIEs().count(DS) &&
"Abstract DIE for this scope exists!");
getAbstractScopeDIEs()[DS] = ScopeDIE;
return ScopeDIE;
}
if (!Scope->getInlinedAt()) {
assert(!LexicalBlockDIEs.count(DS) &&
"Concrete out-of-line DIE for this scope exists!");
LexicalBlockDIEs[DS] = ScopeDIE;
} else {
InlinedLocalScopeDIEs[DS].push_back(ScopeDIE);
}
attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
return ScopeDIE;
}
DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV, bool Abstract) {
auto *VariableDie = DIE::get(DIEValueAllocator, DV.getTag());
insertDIE(DV.getVariable(), VariableDie);
DV.setDIE(*VariableDie);
// Abstract variables don't get common attributes later, so apply them now.
if (Abstract) {
applyCommonDbgVariableAttributes(DV, *VariableDie);
} else {
std::visit(
[&](const auto &V) {
applyConcreteDbgVariableAttributes(V, DV, *VariableDie);
},
DV.asVariant());
}
return VariableDie;
}
void DwarfCompileUnit::applyConcreteDbgVariableAttributes(
const Loc::Single &Single, const DbgVariable &DV, DIE &VariableDie) {
const DbgValueLoc *DVal = &Single.getValueLoc();
if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB() &&
!Single.getExpr()) {
// cuda-gdb special requirement. See NVPTXAS::DWARF_AddressSpace
// Lack of expression means it is a register.
addUInt(VariableDie, dwarf::DW_AT_address_class, dwarf::DW_FORM_data1,
NVPTXAS::DWARF_ADDR_reg_space);
}
if (!DVal->isVariadic()) {
const DbgValueLocEntry *Entry = DVal->getLocEntries().begin();
if (Entry->isLocation()) {
addVariableAddress(DV, VariableDie, Entry->getLoc());
} else if (Entry->isInt()) {
auto *Expr = Single.getExpr();
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(Entry->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, Entry->getInt(), DV.getType());
} else if (Entry->isConstantFP()) {
addConstantFPValue(VariableDie, Entry->getConstantFP());
} else if (Entry->isConstantInt()) {
addConstantValue(VariableDie, Entry->getConstantInt(), DV.getType());
} else if (Entry->isTargetIndexLocation()) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
const DIBasicType *BT = dyn_cast<DIBasicType>(
static_cast<const Metadata *>(DV.getVariable()->getType()));
DwarfDebug::emitDebugLocValue(*Asm, BT, *DVal, DwarfExpr);
addBlock(VariableDie, dwarf::DW_AT_location, DwarfExpr.finalize());
}
return;
}
// If any of the location entries are registers with the value 0,
// then the location is undefined.
if (any_of(DVal->getLocEntries(), [](const DbgValueLocEntry &Entry) {
return Entry.isLocation() && !Entry.getLoc().getReg();
}))
return;
const DIExpression *Expr = Single.getExpr();
assert(Expr && "Variadic Debug Value must have an Expression.");
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
DwarfExpr.addFragmentOffset(Expr);
DIExpressionCursor Cursor(Expr);
const TargetRegisterInfo &TRI = *Asm->MF->getSubtarget().getRegisterInfo();
auto AddEntry = [&](const DbgValueLocEntry &Entry,
DIExpressionCursor &Cursor) {
if (Entry.isLocation()) {
if (!DwarfExpr.addMachineRegExpression(TRI, Cursor,
Entry.getLoc().getReg()))
return false;
} else if (Entry.isInt()) {
// If there is an expression, emit raw unsigned bytes.
DwarfExpr.addUnsignedConstant(Entry.getInt());
} else if (Entry.isConstantFP()) {
// DwarfExpression does not support arguments wider than 64 bits
// (see PR52584).
// TODO: Consider chunking expressions containing overly wide
// arguments into separate pointer-sized fragment expressions.
APInt RawBytes = Entry.getConstantFP()->getValueAPF().bitcastToAPInt();
if (RawBytes.getBitWidth() > 64)
return false;
DwarfExpr.addUnsignedConstant(RawBytes.getZExtValue());
} else if (Entry.isConstantInt()) {
APInt RawBytes = Entry.getConstantInt()->getValue();
if (RawBytes.getBitWidth() > 64)
return false;
DwarfExpr.addUnsignedConstant(RawBytes.getZExtValue());
} else if (Entry.isTargetIndexLocation()) {
TargetIndexLocation Loc = Entry.getTargetIndexLocation();
// TODO TargetIndexLocation is a target-independent. Currently
// only the WebAssembly-specific encoding is supported.
assert(Asm->TM.getTargetTriple().isWasm());
DwarfExpr.addWasmLocation(Loc.Index, static_cast<uint64_t>(Loc.Offset));
} else {
llvm_unreachable("Unsupported Entry type.");
}
return true;
};
if (!DwarfExpr.addExpression(
std::move(Cursor),
[&](unsigned Idx, DIExpressionCursor &Cursor) -> bool {
return AddEntry(DVal->getLocEntries()[Idx], Cursor);
}))
return;
// Now attach the location information to the DIE.
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);
}
void DwarfCompileUnit::applyConcreteDbgVariableAttributes(
const Loc::Multi &Multi, const DbgVariable &DV, DIE &VariableDie) {
addLocationList(VariableDie, dwarf::DW_AT_location,
Multi.getDebugLocListIndex());
auto TagOffset = Multi.getDebugLocListTagOffset();
if (TagOffset)
addUInt(VariableDie, dwarf::DW_AT_LLVM_tag_offset, dwarf::DW_FORM_data1,
*TagOffset);
}
void DwarfCompileUnit::applyConcreteDbgVariableAttributes(const Loc::MMI &MMI,
const DbgVariable &DV,
DIE &VariableDie) {
std::optional<unsigned> NVPTXAddressSpace;
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
for (const auto &Fragment : MMI.getFrameIndexExprs()) {
Register FrameReg;
const DIExpression *Expr = Fragment.Expr;
const TargetFrameLowering *TFI = Asm->MF->getSubtarget().getFrameLowering();
StackOffset Offset =
TFI->getFrameIndexReference(*Asm->MF, Fragment.FI, FrameReg);
DwarfExpr.addFragmentOffset(Expr);
auto *TRI = Asm->MF->getSubtarget().getRegisterInfo();
SmallVector<uint64_t, 8> Ops;
TRI->getOffsetOpcodes(Offset, Ops);
// cuda-gdb special requirement. See NVPTXAS::DWARF_AddressSpace.
// Decode DW_OP_constu <DWARF Address Space> DW_OP_swap
// DW_OP_xderef sequence to specify address space.
if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB()) {
unsigned LocalNVPTXAddressSpace;
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()) {
// cuda-gdb special requirement. See NVPTXAS::DWARF_AddressSpace.
addUInt(VariableDie, dwarf::DW_AT_address_class, dwarf::DW_FORM_data1,
NVPTXAddressSpace.value_or(NVPTXAS::DWARF_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);
}
void DwarfCompileUnit::applyConcreteDbgVariableAttributes(
const Loc::EntryValue &EntryValue, const DbgVariable &DV,
DIE &VariableDie) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
// Emit each expression as: EntryValue(Register) <other ops> <Fragment>.
for (auto [Register, Expr] : EntryValue.EntryValues) {
DwarfExpr.addFragmentOffset(&Expr);
DIExpressionCursor Cursor(Expr.getElements());
DwarfExpr.beginEntryValueExpression(Cursor);
DwarfExpr.addMachineRegExpression(
*Asm->MF->getSubtarget().getRegisterInfo(), Cursor, Register);
DwarfExpr.addExpression(std::move(Cursor));
}
addBlock(VariableDie, dwarf::DW_AT_location, DwarfExpr.finalize());
}
void DwarfCompileUnit::applyConcreteDbgVariableAttributes(
const std::monostate &, const DbgVariable &DV, DIE &VariableDie) {}
DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV,
const LexicalScope &Scope,
DIE *&ObjectPointer) {
auto Var = constructVariableDIE(DV, Scope.isAbstractScope());
if (DV.isObjectPointer())
ObjectPointer = Var;
return Var;
}
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;
}
/// 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;
if (auto *DLVar = Array->getDataLocation())
Result.push_back(DLVar);
if (auto *AsVar = Array->getAssociated())
Result.push_back(AsVar);
if (auto *AlVar = Array->getAllocated())
Result.push_back(AlVar);
for (auto *El : Array->getElements()) {
if (auto *Subrange = dyn_cast<DISubrange>(El)) {
if (auto Count = Subrange->getCount())
if (auto *Dependency = dyn_cast_if_present<DIVariable *>(Count))
Result.push_back(Dependency);
if (auto LB = Subrange->getLowerBound())
if (auto *Dependency = dyn_cast_if_present<DIVariable *>(LB))
Result.push_back(Dependency);
if (auto UB = Subrange->getUpperBound())
if (auto *Dependency = dyn_cast_if_present<DIVariable *>(UB))
Result.push_back(Dependency);
if (auto ST = Subrange->getStride())
if (auto *Dependency = dyn_cast_if_present<DIVariable *>(ST))
Result.push_back(Dependency);
} else if (auto *GenericSubrange = dyn_cast<DIGenericSubrange>(El)) {
if (auto Count = GenericSubrange->getCount())
if (auto *Dependency = dyn_cast_if_present<DIVariable *>(Count))
Result.push_back(Dependency);
if (auto LB = GenericSubrange->getLowerBound())
if (auto *Dependency = dyn_cast_if_present<DIVariable *>(LB))
Result.push_back(Dependency);
if (auto UB = GenericSubrange->getUpperBound())
if (auto *Dependency = dyn_cast_if_present<DIVariable *>(UB))
Result.push_back(Dependency);
if (auto ST = GenericSubrange->getStride())
if (auto *Dependency = dyn_cast_if_present<DIVariable *>(ST))
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();
assert(Var);
// 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 (const auto *Dependency : dependencies(Var)) {
// Don't add dependency if it is in a different lexical scope or a global.
if (const auto *Dep = dyn_cast<const DILocalVariable>(Dependency))
if (DbgVariable *Var = DbgVar.lookup(Dep))
WorkList.push_back({Var, 0});
}
}
return Result;
}
DIE &DwarfCompileUnit::constructSubprogramScopeDIE(const DISubprogram *Sub,
const Function &F,
LexicalScope *Scope,
MCSymbol *LineTableSym) {
DIE &ScopeDIE = updateSubprogramScopeDIE(Sub, F, LineTableSym);
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.
DITypeArray 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) {
DIE *ObjectPointer = nullptr;
// Emit function arguments (order is significant).
auto Vars = DU->getScopeVariables().lookup(Scope);
for (auto &DV : Vars.Args)
ScopeDIE.addChild(constructVariableDIE(*DV.second, *Scope, ObjectPointer));
// Emit local variables.
auto Locals = sortLocalVars(Vars.Locals);
for (DbgVariable *DV : Locals)
ScopeDIE.addChild(constructVariableDIE(*DV, *Scope, ObjectPointer));
// Emit labels.
for (DbgLabel *DL : DU->getScopeLabels().lookup(Scope))
ScopeDIE.addChild(constructLabelDIE(*DL, *Scope));
// Track other local entities (skipped in gmlt-like data).
// This creates mapping between CU and a set of local declarations that
// should be emitted for subprograms in this CU.
if (!includeMinimalInlineScopes() && !Scope->getInlinedAt()) {
auto &LocalDecls = DD->getLocalDeclsForScope(Scope->getScopeNode());
DeferredLocalDecls.insert_range(LocalDecls);
}
// Emit inner lexical scopes.
auto skipLexicalScope = [this](LexicalScope *S) -> bool {
if (isa<DISubprogram>(S->getScopeNode()))
return false;
auto Vars = DU->getScopeVariables().lookup(S);
if (!Vars.Args.empty() || !Vars.Locals.empty())
return false;
return includeMinimalInlineScopes() ||
DD->getLocalDeclsForScope(S->getScopeNode()).empty();
};
for (LexicalScope *LS : Scope->getChildren()) {
// If the lexical block doesn't have non-scope children, skip
// its emission and put its children directly to the parent scope.
if (skipLexicalScope(LS))
createAndAddScopeChildren(LS, ScopeDIE);
else
constructScopeDIE(LS, ScopeDIE);
}
return ObjectPointer;
}
DIE &DwarfCompileUnit::getOrCreateAbstractSubprogramDIE(
const DISubprogram *SP) {
if (auto *AbsDef = getAbstractScopeDIEs().lookup(SP))
return *AbsDef;
auto [ContextDIE, ContextCU] = getOrCreateAbstractSubprogramContextDIE(SP);
return createAbstractSubprogramDIE(SP, ContextDIE, ContextCU);
}
DIE &DwarfCompileUnit::createAbstractSubprogramDIE(
const DISubprogram *SP, DIE *ContextDIE, DwarfCompileUnit *ContextCU) {
// Passing null as the associated node because the abstract definition
// shouldn't be found by lookup.
DIE &AbsDef = ContextCU->createAndAddDIE(dwarf::DW_TAG_subprogram,
*ContextDIE, nullptr);
// Store the DIE before creating children.
ContextCU->getAbstractScopeDIEs()[SP] = &AbsDef;
ContextCU->applySubprogramAttributesToDefinition(SP, AbsDef);
ContextCU->addSInt(AbsDef, dwarf::DW_AT_inline,
DD->getDwarfVersion() <= 4 ? std::optional<dwarf::Form>()
: dwarf::DW_FORM_implicit_const,
dwarf::DW_INL_inlined);
return AbsDef;
}
std::pair<DIE *, DwarfCompileUnit *>
DwarfCompileUnit::getOrCreateAbstractSubprogramContextDIE(
const DISubprogram *SP) {
bool Minimal = includeMinimalInlineScopes();
bool IgnoreScope = shouldPlaceInUnitDIE(SP, Minimal);
DIE *ContextDIE = getOrCreateSubprogramContextDIE(SP, IgnoreScope);
if (auto *SPDecl = SP->getDeclaration())
if (!Minimal)
getOrCreateSubprogramDIE(SPDecl, nullptr);
// 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.
auto *ContextCU = IgnoreScope ? this : DD->lookupCU(ContextDIE->getUnitDie());
return std::make_pair(ContextDIE, ContextCU);
}
void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
LexicalScope *Scope) {
auto *SP = cast<DISubprogram>(Scope->getScopeNode());
// Populate subprogram DIE only once.
if (!getFinalizedAbstractSubprograms().insert(SP).second)
return;
auto [ContextDIE, ContextCU] = getOrCreateAbstractSubprogramContextDIE(SP);
DIE *AbsDef = getAbstractScopeDIEs().lookup(SP);
if (!AbsDef)
AbsDef = &createAbstractSubprogramDIE(SP, ContextDIE, ContextCU);
if (DIE *ObjectPointer = ContextCU->createAndAddScopeChildren(Scope, *AbsDef))
ContextCU->addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer,
*ObjectPointer);
}
bool DwarfCompileUnit::useGNUAnalogForDwarf5Feature() const {
return DD->getDwarfVersion() <= 4 && !DD->tuneForLLDB();
}
dwarf::Tag DwarfCompileUnit::getDwarf5OrGNUTag(dwarf::Tag Tag) const {
if (!useGNUAnalogForDwarf5Feature())
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())
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_target_clobbered:
return dwarf::DW_AT_GNU_call_site_target_clobbered;
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())
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, const DISubprogram *CalleeSP, const Function *CalleeF,
bool IsTail, const MCSymbol *PCAddr, const MCSymbol *CallAddr,
MachineLocation CallTarget, int64_t Offset, DIType *AllocSiteTy) {
// Insert a call site entry DIE within ScopeDIE.
DIE &CallSiteDIE = createAndAddDIE(getDwarf5OrGNUTag(dwarf::DW_TAG_call_site),
ScopeDIE, nullptr);
// A valid register in CallTarget indicates an indirect call.
if (CallTarget.getReg()) {
// Add a DW_AT_call_target location expression describing the location of
// the address of the target function. If any register in the expression
// (i.e., the single register we currently handle) is volatile we must use
// DW_AT_call_target_clobbered instead.
const TargetRegisterInfo &TRI = *Asm->MF->getSubtarget().getRegisterInfo();
dwarf::Attribute Attribute = getDwarf5OrGNUAttr(
TRI.isCalleeSavedPhysReg(CallTarget.getReg(), *Asm->MF)
? dwarf::DW_AT_call_target
: dwarf::DW_AT_call_target_clobbered);
// CallTarget is the location of the address of an indirect call. The
// location may be indirect, modified by Offset.
if (CallTarget.isIndirect())
addMemoryLocation(CallSiteDIE, Attribute, CallTarget, Offset);
else
addAddress(CallSiteDIE, Attribute, CallTarget);
} else if (CalleeSP) {
DIE *CalleeDIE = getOrCreateSubprogramDIE(CalleeSP, CalleeF);
assert(CalleeDIE && "Could not create DIE for call site entry origin");
if (AddLinkageNamesToDeclCallOriginsForTuning(DD) &&
!CalleeSP->isDefinition() &&
!CalleeDIE->findAttribute(dwarf::DW_AT_linkage_name)) {
addLinkageName(*CalleeDIE, CalleeSP->getLinkageName());
}
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 address of the branch instruction to allow the debugger to
// show where the tail call occurred. This attribute has no GNU analog.
//
// GDB works backwards from non-standard usage of DW_AT_low_pc (in DWARF4
// mode -- equivalently, in DWARF5 mode, DW_AT_call_return_pc) at tail-call
// site entries to figure out the PC of tail-calling branch instructions.
// This means it doesn't need the compiler to emit DW_AT_call_pc, so we
// don't emit it here.
//
// There's no need to tie non-GDB debuggers to this non-standardness, as it
// adds unnecessary complexity to the debugger. For non-GDB debuggers, emit
// the standard DW_AT_call_pc info.
if (!useGNUAnalogForDwarf5Feature())
addLabelAddress(CallSiteDIE, dwarf::DW_AT_call_pc, CallAddr);
}
// 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
// GDB expects it in DWARF4 mode, even for tail calls (see the comment above
// the DW_AT_call_pc emission logic for an explanation).
if (!IsTail || useGNUAnalogForDwarf5Feature()) {
assert(PCAddr && "Missing return PC information for a call");
addLabelAddress(CallSiteDIE,
getDwarf5OrGNUAttr(dwarf::DW_AT_call_return_pc), PCAddr);
}
if (AllocSiteTy)
addType(CallSiteDIE, AllocSiteTy, dwarf::DW_AT_LLVM_alloc_type);
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, 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)) {
// If there is an abstract subprogram, refer to it. Note that this assumes
// that all the abstract subprograms have been already created (which is
// correct until imported entities get emitted in DwarfDebug::endModule()).
if (auto *AbsSPDie = getAbstractScopeDIEs().lookup(SP))
EntityDie = AbsSPDie;
else
EntityDie = getOrCreateSubprogramDIE(SP, nullptr);
} else if (auto *T = dyn_cast<DIType>(Entity))
EntityDie = getOrCreateTypeDIE(T);
else if (auto *GV = dyn_cast<DIGlobalVariable>(Entity))
EntityDie = getOrCreateGlobalVariableDIE(GV, {});
else if (auto *IE = dyn_cast<DIImportedEntity>(Entity))
EntityDie = getOrCreateImportedEntityDIE(IE);
else
EntityDie = getDIE(Entity);
assert(EntityDie);
addSourceLine(*IMDie, Module->getLine(), /*Column*/ 0, Module->getFile());
addDIEEntry(*IMDie, dwarf::DW_AT_import, *EntityDie);
StringRef Name = Module->getName();
if (!Name.empty()) {
addString(*IMDie, dwarf::DW_AT_name, Name);
// FIXME: if consumers ever start caring about handling
// unnamed import declarations such as `using ::nullptr_t`
// or `using namespace std::ranges`, we could add the
// import declaration into the accelerator table with the
// name being the one of the entity being imported.
DD->addAccelNamespace(*this, CUNode->getNameTableKind(), Name, *IMDie);
}
// This is for imported module with renamed entities (such as variables and
// subprograms).
DINodeArray Elements = Module->getElements();
for (const auto *Element : Elements) {
if (!Element)
continue;
IMDie->addChild(
constructImportedEntityDIE(cast<DIImportedEntity>(Element)));
}
return IMDie;
}
DIE *DwarfCompileUnit::getOrCreateImportedEntityDIE(
const DIImportedEntity *IE) {
// Check for pre-existence.
if (DIE *Die = getDIE(IE))
return Die;
DIE *ContextDIE = getOrCreateContextDIE(IE->getScope());
assert(ContextDIE && "Empty scope for the imported entity!");
DIE *IMDie = constructImportedEntityDIE(IE);
ContextDIE->addChild(IMDie);
return IMDie;
}
void DwarfCompileUnit::finishSubprogramDefinition(const DISubprogram *SP) {
DIE *D = getDIE(SP);
if (DIE *AbsSPDIE = getAbstractScopeDIEs().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))
applyCommonDbgVariableAttributes(*Var, *Die);
else if ((Label = dyn_cast<const DbgLabel>(Entity)))
applyLabelAttributes(*Label, *Die);
else
llvm_unreachable("DbgEntity must be DbgVariable or DbgLabel.");
}
if (!Label)
return;
const auto *Sym = Label->getSymbol();
if (!Sym)
return;
addLabelAddress(*Die, dwarf::DW_AT_low_pc, Sym);
// A TAG_label with a name and an AT_low_pc must be placed in debug_names.
if (StringRef Name = Label->getName(); !Name.empty())
getDwarfDebug().addAccelName(*this, CUNode->getNameTableKind(), Name, *Die);
}
void DwarfCompileUnit::attachLexicalScopesAbstractOrigins() {
auto AttachAO = [&](const DILocalScope *LS, DIE *ScopeDIE) {
if (auto *AbsLSDie = getAbstractScopeDIEs().lookup(LS))
addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *AbsLSDie);
};
for (auto [LScope, ScopeDIE] : LexicalBlockDIEs)
AttachAO(LScope, ScopeDIE);
for (auto &[LScope, ScopeDIEs] : InlinedLocalScopeDIEs)
for (auto *ScopeDIE : ScopeDIEs)
AttachAO(LScope, ScopeDIE);
}
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::Apple:
return false;
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::addGlobalTypeImpl(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) {
auto *Single = std::get_if<Loc::Single>(&DV);
if (Single && Single->getExpr())
addComplexAddress(Single->getExpr(), Die, dwarf::DW_AT_location, Location);
else
addAddress(Die, dwarf::DW_AT_location, Location);
}
void DwarfCompileUnit::addLocationWithExpr(DIE &Die, dwarf::Attribute Attribute,
const MachineLocation &Location,
ArrayRef<uint64_t> Expr) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
if (Location.isIndirect())
DwarfExpr.setMemoryLocationKind();
DIExpressionCursor Cursor(Expr);
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 an address attribute to a die based on the location provided.
void DwarfCompileUnit::addAddress(DIE &Die, dwarf::Attribute Attribute,
const MachineLocation &Location) {
addLocationWithExpr(Die, Attribute, Location, {});
}
/// Add a memory location exprloc to \p DIE with attribute \p Attribute
/// at \p Location + \p Offset.
void DwarfCompileUnit::addMemoryLocation(DIE &Die, dwarf::Attribute Attribute,
const MachineLocation &Location,
int64_t Offset) {
assert(Location.isIndirect() && "Memory loc should be indirect");
SmallVector<uint64_t, 3> Ops;
DIExpression::appendOffset(Ops, Offset);
addLocationWithExpr(Die, Attribute, Location, Ops);
}
/// 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 DIExpression *DIExpr, DIE &Die,
dwarf::Attribute Attribute,
const MachineLocation &Location) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
DwarfExpr.addFragmentOffset(DIExpr);
DwarfExpr.setLocation(Location, DIExpr);
DIExpressionCursor Cursor(DIExpr);
if (DIExpr->isEntryValue())
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 = (DD->getDwarfVersion() >= 5)
? dwarf::DW_FORM_loclistx
: DD->getDwarfSectionOffsetForm();
addAttribute(Die, Attribute, Form, DIELocList(Index));
}
void DwarfCompileUnit::applyCommonDbgVariableAttributes(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);
addAnnotation(VariableDie, DIVar->getAnnotations());
}
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);
if (DILabel->isArtificial())
addFlag(LabelDie, dwarf::DW_AT_artificial);
if (DILabel->getCoroSuspendIdx())
addUInt(LabelDie, dwarf::DW_AT_LLVM_coro_suspend_idx, std::nullopt,
*DILabel->getCoroSuspendIdx());
}
/// Add a Dwarf expression attribute data and value.
void DwarfCompileUnit::addExpr(DIELoc &Die, dwarf::Form Form,
const MCExpr *Expr) {
addAttribute(Die, (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);
}
bool DwarfCompileUnit::emitFuncLineTableOffsets() const {
return EmitFuncLineTableOffsetsOption;
}
void DwarfCompileUnit::addAddrTableBase() {
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
MCSymbol *Label = DD->getAddressPool().getLabel();
addSectionLabel(getUnitDie(),
DD->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) {
addAttribute(Die, (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);
// Round up to smallest number of bytes that contains this number of bits.
// ExprRefedBaseTypes is populated with types referenced by
// DW_OP_LLVM_convert operations in location expressions. These are often
// byte-sized, but one common counter-example is 1-bit sized conversions
// from `i1` types. TODO: Should these use DW_AT_bit_size? See
// DwarfUnit::constructTypeDIE.
addUInt(Die, dwarf::DW_AT_byte_size, std::nullopt,
divideCeil(Btr.BitSize, 8));
Btr.Die = &Die;
}
}
DIE *DwarfCompileUnit::getLocalContextDIE(const DILexicalBlock *LB) {
// Assume if there is an abstract tree all the DIEs are already emitted.
bool isAbstract = getAbstractScopeDIEs().count(LB->getSubprogram());
if (isAbstract) {
auto &DIEs = getAbstractScopeDIEs();
if (auto It = DIEs.find(LB); It != DIEs.end())
return It->second;
}
assert(!isAbstract && "Missed lexical block DIE in abstract tree!");
// Check if we have a concrete DIE.
if (auto It = LexicalBlockDIEs.find(LB); It != LexicalBlockDIEs.end())
return It->second;
// If nothing available found, we cannot just create a new lexical block,
// because it isn't known where to put it into the DIE tree.
// So, we may only try to find the most close avaiable parent DIE.
return getOrCreateContextDIE(LB->getScope()->getNonLexicalBlockFileScope());
}
DIE *DwarfCompileUnit::getOrCreateContextDIE(const DIScope *Context) {
if (isa_and_nonnull<DILocalScope>(Context)) {
if (auto *LFScope = dyn_cast<DILexicalBlockFile>(Context))
Context = LFScope->getNonLexicalBlockFileScope();
if (auto *LScope = dyn_cast<DILexicalBlock>(Context))
return getLocalContextDIE(LScope);
// Otherwise the context must be a DISubprogram.
auto *SPScope = cast<DISubprogram>(Context);
const auto &DIEs = getAbstractScopeDIEs();
if (auto It = DIEs.find(SPScope); It != DIEs.end())
return It->second;
}
return DwarfUnit::getOrCreateContextDIE(Context);
}
DIE *DwarfCompileUnit::getOrCreateSubprogramDIE(const DISubprogram *SP,
const Function *F,
bool Minimal) {
if (!F && SP->isDefinition()) {
F = DD->getLexicalScopes().getFunction(SP);
if (!F) {
// SP may belong to another CU. Determine the CU similarly
// to DwarfDebug::constructAbstractSubprogramScopeDIE.
return &DD->getOrCreateAbstractSubprogramCU(SP, *this)
.getOrCreateAbstractSubprogramDIE(SP);
}
}
return DwarfUnit::getOrCreateSubprogramDIE(SP, F, Minimal);
}
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