llvm-6502/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
David Blaikie f49ead7098 Provide gmlt-like inline scope information in the skeleton CU to facilitate symbolication without needing the .dwo files
Clang -gsplit-dwarf self-host -O0, binary increases by 0.0005%, -O2,
binary increases by 25%.

A large binary inside Google, split-dwarf, -O0, and other internal flags
(GDB index, etc) increases by 1.8%, optimized build is 35%.

The size impact may be somewhat greater in .o files (I haven't measured
that much - since the linked executable -O0 numbers seemed low enough)
due to relocations. These relocations could be removed if we taught the
llvm-symbolizer to handle indexed addressing in the .o file (GDB can't
cope with this just yet, but GDB won't be reading this info anyway).
Also debug_ranges could be shared between .o and .dwo, though ideally
debug_ranges would get a schema that could used index(+offset)
addressing, and move to the .dwo file, then we'd be back to sharing
addresses in the address pool again.

But for now, these sizes seem small enough to go ahead with this.

Verified that no other DW_TAGs are produced into the .o file other than
subprograms and inlined_subroutines.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221306 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-04 22:12:25 +00:00

251 lines
9.2 KiB
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//===-- llvm/CodeGen/DwarfCompileUnit.h - Dwarf Compile Unit ---*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains support for writing dwarf compile unit.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DWARFCOMPILEUNIT_H
#define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFCOMPILEUNIT_H
#include "DwarfUnit.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/IR/DebugInfo.h"
namespace llvm {
class AsmPrinter;
class DIE;
class DwarfDebug;
class DwarfFile;
class MCSymbol;
class LexicalScope;
class DwarfCompileUnit : public DwarfUnit {
/// The attribute index of DW_AT_stmt_list in the compile unit DIE, avoiding
/// the need to search for it in applyStmtList.
unsigned stmtListIndex;
/// Skeleton unit associated with this unit.
DwarfCompileUnit *Skeleton;
/// A label at the start of the non-dwo section related to this unit.
MCSymbol *SectionSym;
/// The start of the unit within its section.
MCSymbol *LabelBegin;
/// GlobalNames - A map of globally visible named entities for this unit.
StringMap<const DIE *> GlobalNames;
/// GlobalTypes - A map of globally visible types for this unit.
StringMap<const DIE *> GlobalTypes;
// List of range lists for a given compile unit, separate from the ranges for
// the CU itself.
SmallVector<RangeSpanList, 1> CURangeLists;
// List of ranges for a given compile unit.
SmallVector<RangeSpan, 2> CURanges;
// The base address of this unit, if any. Used for relative references in
// ranges/locs.
const MCSymbol *BaseAddress;
/// \brief Construct a DIE for the given DbgVariable without initializing the
/// DbgVariable's DIE reference.
std::unique_ptr<DIE> constructVariableDIEImpl(const DbgVariable &DV,
bool Abstract);
bool isDwoUnit() const override;
bool includeMinimalInlineScopes() const;
public:
DwarfCompileUnit(unsigned UID, DICompileUnit Node, AsmPrinter *A,
DwarfDebug *DW, DwarfFile *DWU);
DwarfCompileUnit *getSkeleton() const {
return Skeleton;
}
void initStmtList(MCSymbol *DwarfLineSectionSym);
/// Apply the DW_AT_stmt_list from this compile unit to the specified DIE.
void applyStmtList(DIE &D);
/// getOrCreateGlobalVariableDIE - get or create global variable DIE.
DIE *getOrCreateGlobalVariableDIE(DIGlobalVariable GV);
/// addLabelAddress - Add a dwarf label attribute data and value using
/// either DW_FORM_addr or DW_FORM_GNU_addr_index.
void addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Label);
/// addLocalLabelAddress - Add a dwarf label attribute data and value using
/// DW_FORM_addr only.
void addLocalLabelAddress(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Label);
/// addSectionDelta - Add a label delta attribute data and value.
void addSectionDelta(DIE &Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
const MCSymbol *Lo);
DwarfCompileUnit &getCU() override { return *this; }
unsigned getOrCreateSourceID(StringRef FileName, StringRef DirName) override;
/// addRange - Add an address range to the list of ranges for this unit.
void addRange(RangeSpan Range);
void attachLowHighPC(DIE &D, const MCSymbol *Begin, const MCSymbol *End);
/// addSectionLabel - Add a Dwarf section label attribute data and value.
///
void addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Label, const MCSymbol *Sec);
/// \brief 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 &updateSubprogramScopeDIE(DISubprogram SP);
void constructScopeDIE(LexicalScope *Scope,
SmallVectorImpl<std::unique_ptr<DIE>> &FinalChildren);
/// \brief A helper function to construct a RangeSpanList for a given
/// lexical scope.
void addScopeRangeList(DIE &ScopeDIE, SmallVector<RangeSpan, 2> Range);
void attachRangesOrLowHighPC(DIE &D, SmallVector<RangeSpan, 2> Ranges);
void attachRangesOrLowHighPC(DIE &D,
const SmallVectorImpl<InsnRange> &Ranges);
/// \brief This scope represents inlined body of a function. Construct
/// DIE to represent this concrete inlined copy of the function.
std::unique_ptr<DIE> constructInlinedScopeDIE(LexicalScope *Scope);
/// \brief Construct new DW_TAG_lexical_block for this scope and
/// attach DW_AT_low_pc/DW_AT_high_pc labels.
std::unique_ptr<DIE> constructLexicalScopeDIE(LexicalScope *Scope);
/// constructVariableDIE - Construct a DIE for the given DbgVariable.
std::unique_ptr<DIE> constructVariableDIE(DbgVariable &DV,
bool Abstract = false);
std::unique_ptr<DIE> constructVariableDIE(DbgVariable &DV,
const LexicalScope &Scope,
DIE *&ObjectPointer);
/// A helper function to create children of a Scope DIE.
DIE *createScopeChildrenDIE(LexicalScope *Scope,
SmallVectorImpl<std::unique_ptr<DIE>> &Children,
unsigned *ChildScopeCount = nullptr);
/// \brief Construct a DIE for this subprogram scope.
void constructSubprogramScopeDIE(LexicalScope *Scope);
DIE *createAndAddScopeChildren(LexicalScope *Scope, DIE &ScopeDIE);
void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
/// \brief Construct import_module DIE.
std::unique_ptr<DIE>
constructImportedEntityDIE(const DIImportedEntity &Module);
void finishSubprogramDefinition(DISubprogram SP);
void collectDeadVariables(DISubprogram SP);
/// Set the skeleton unit associated with this unit.
void setSkeleton(DwarfCompileUnit &Skel) { Skeleton = &Skel; }
MCSymbol *getSectionSym() const {
assert(Section);
return SectionSym;
}
/// Pass in the SectionSym even though we could recreate it in every compile
/// unit (type units will have actually distinct symbols once they're in
/// comdat sections).
void initSection(const MCSection *Section, MCSymbol *SectionSym) {
DwarfUnit::initSection(Section);
this->SectionSym = SectionSym;
// Don't bother labeling the .dwo unit, as its offset isn't used.
if (!Skeleton)
LabelBegin =
Asm->GetTempSymbol(Section->getLabelBeginName(), getUniqueID());
}
unsigned getLength() {
return sizeof(uint32_t) + // Length field
getHeaderSize() + UnitDie.getSize();
}
void emitHeader(const MCSymbol *ASectionSym) const override;
MCSymbol *getLabelBegin() const {
assert(Section);
return LabelBegin;
}
/// Add a new global name to the compile unit.
void addGlobalName(StringRef Name, DIE &Die, DIScope Context) override;
/// Add a new global type to the compile unit.
void addGlobalType(DIType Ty, const DIE &Die, DIScope Context) override;
const StringMap<const DIE *> &getGlobalNames() const { return GlobalNames; }
const StringMap<const DIE *> &getGlobalTypes() const { return GlobalTypes; }
/// Add DW_AT_location attribute for a DbgVariable based on provided
/// MachineLocation.
void addVariableAddress(const DbgVariable &DV, DIE &Die,
MachineLocation Location);
/// Add an address attribute to a die based on the location provided.
void addAddress(DIE &Die, dwarf::Attribute Attribute,
const MachineLocation &Location, bool Indirect = false);
/// Start with the address based on the location provided, and generate the
/// DWARF information necessary to find the actual variable (navigating the
/// extra location information encoded in the type) based on the starting
/// location. Add the DWARF information to the die.
void addComplexAddress(const DbgVariable &DV, DIE &Die,
dwarf::Attribute Attribute,
const MachineLocation &Location);
/// Add a Dwarf loclistptr attribute data and value.
void addLocationList(DIE &Die, dwarf::Attribute Attribute, unsigned Index);
void applyVariableAttributes(const DbgVariable &Var, DIE &VariableDie);
/// Add a Dwarf expression attribute data and value.
void addExpr(DIELoc &Die, dwarf::Form Form, const MCExpr *Expr);
void applySubprogramAttributesToDefinition(DISubprogram SP, DIE &SPDie);
/// getRangeLists - Get the vector of range lists.
const SmallVectorImpl<RangeSpanList> &getRangeLists() const {
return (Skeleton ? Skeleton : this)->CURangeLists;
}
/// getRanges - Get the list of ranges for this unit.
const SmallVectorImpl<RangeSpan> &getRanges() const { return CURanges; }
SmallVector<RangeSpan, 2> takeRanges() { return std::move(CURanges); }
void setBaseAddress(const MCSymbol *Base) { BaseAddress = Base; }
const MCSymbol *getBaseAddress() const { return BaseAddress; }
};
} // end llvm namespace
#endif