llvm-project/llvm/tools/llvm-pdbdump/PrettyClassLayoutGraphicalDumper.cpp
Zachary Turner f5cdd40f89 [llvm-pdbdump] Don't crash when displaying padding.
We have a lot of complicated logic to determine where padding
is in a record, and the debug info doesn't always provide enough
information to figure it out with laser precision.  In this case
we were putting the padding in the wrong place causing an
out of bounds access on a BitVector.

Right now we decide that any trailing padding of a child type
will be truncated during record layout, but this is only true
insofar as the class still is sized properly to end on an
alignment boundary, which the algorithm doesn't yet know about.

For now, just don't crash, even though we display padding twice
in this case.

llvm-svn: 303946
2017-05-26 00:15:15 +00:00

217 lines
6.9 KiB
C++

//===- PrettyClassLayoutGraphicalDumper.h -----------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "PrettyClassLayoutGraphicalDumper.h"
#include "LinePrinter.h"
#include "PrettyClassDefinitionDumper.h"
#include "PrettyEnumDumper.h"
#include "PrettyFunctionDumper.h"
#include "PrettyTypedefDumper.h"
#include "PrettyVariableDumper.h"
#include "PrettyVariableDumper.h"
#include "llvm-pdbdump.h"
#include "llvm/DebugInfo/PDB/PDBSymbolData.h"
#include "llvm/DebugInfo/PDB/PDBSymbolTypeBaseClass.h"
#include "llvm/DebugInfo/PDB/PDBSymbolTypeUDT.h"
#include "llvm/DebugInfo/PDB/UDTLayout.h"
#include "llvm/Support/Format.h"
using namespace llvm;
using namespace llvm::pdb;
PrettyClassLayoutGraphicalDumper::PrettyClassLayoutGraphicalDumper(
LinePrinter &P, uint32_t RecurseLevel, uint32_t InitialOffset)
: PDBSymDumper(true), Printer(P), RecursionLevel(RecurseLevel),
ClassOffsetZero(InitialOffset), CurrentAbsoluteOffset(InitialOffset) {}
bool PrettyClassLayoutGraphicalDumper::start(const UDTLayoutBase &Layout) {
if (RecursionLevel == 1 &&
opts::pretty::ClassFormat == opts::pretty::ClassDefinitionFormat::All) {
for (auto &Other : Layout.other_items())
Other->dump(*this);
for (auto &Func : Layout.funcs())
Func->dump(*this);
}
const BitVector &UseMap = Layout.usedBytes();
int NextPaddingByte = UseMap.find_first_unset();
for (auto &Item : Layout.layout_items()) {
// Calculate the absolute offset of the first byte of the next field.
uint32_t RelativeOffset = Item->getOffsetInParent();
CurrentAbsoluteOffset = ClassOffsetZero + RelativeOffset;
// Since there is storage there, it should be set! However, this might
// be an empty base, in which case it could extend outside the bounds of
// the parent class.
if (RelativeOffset < UseMap.size() && (Item->getSize() > 0)) {
assert(UseMap.test(RelativeOffset));
// If there is any remaining padding in this class, and the offset of the
// new item is after the padding, then we must have just jumped over some
// padding. Print a padding row and then look for where the next block
// of padding begins.
if ((NextPaddingByte >= 0) &&
(RelativeOffset > uint32_t(NextPaddingByte))) {
printPaddingRow(RelativeOffset - NextPaddingByte);
NextPaddingByte = UseMap.find_next_unset(RelativeOffset);
}
}
CurrentItem = Item;
if (Item->isVBPtr()) {
VTableLayoutItem &Layout = static_cast<VTableLayoutItem &>(*CurrentItem);
VariableDumper VarDumper(Printer);
VarDumper.startVbptr(CurrentAbsoluteOffset, Layout.getSize());
} else {
if (auto Sym = Item->getSymbol())
Sym->dump(*this);
}
if (Item->getLayoutSize() > 0) {
uint32_t Prev = RelativeOffset + Item->getLayoutSize() - 1;
if (Prev < UseMap.size())
NextPaddingByte = UseMap.find_next_unset(Prev);
}
}
auto TailPadding = Layout.tailPadding();
if (TailPadding > 0) {
if (TailPadding != 1 || Layout.getSize() != 1) {
Printer.NewLine();
WithColor(Printer, PDB_ColorItem::Padding).get()
<< "<padding> (" << TailPadding << " bytes)";
DumpedAnything = true;
}
}
return DumpedAnything;
}
void PrettyClassLayoutGraphicalDumper::printPaddingRow(uint32_t Amount) {
if (Amount == 0)
return;
Printer.NewLine();
WithColor(Printer, PDB_ColorItem::Padding).get() << "<padding> (" << Amount
<< " bytes)";
DumpedAnything = true;
}
void PrettyClassLayoutGraphicalDumper::dump(
const PDBSymbolTypeBaseClass &Symbol) {
assert(CurrentItem != nullptr);
Printer.NewLine();
BaseClassLayout &Layout = static_cast<BaseClassLayout &>(*CurrentItem);
std::string Label = "base";
if (Layout.isVirtualBase()) {
Label.insert(Label.begin(), 'v');
if (Layout.getBase().isIndirectVirtualBaseClass())
Label.insert(Label.begin(), 'i');
}
Printer << Label << " ";
uint32_t Size = Layout.isEmptyBase() ? 1 : Layout.getLayoutSize();
WithColor(Printer, PDB_ColorItem::Offset).get()
<< "+" << format_hex(CurrentAbsoluteOffset, 4) << " [sizeof=" << Size
<< "] ";
WithColor(Printer, PDB_ColorItem::Identifier).get() << Layout.getName();
if (shouldRecurse()) {
Printer.Indent();
uint32_t ChildOffsetZero = ClassOffsetZero + Layout.getOffsetInParent();
PrettyClassLayoutGraphicalDumper BaseDumper(Printer, RecursionLevel + 1,
ChildOffsetZero);
DumpedAnything |= BaseDumper.start(Layout);
Printer.Unindent();
}
DumpedAnything = true;
}
bool PrettyClassLayoutGraphicalDumper::shouldRecurse() const {
uint32_t Limit = opts::pretty::ClassRecursionDepth;
if (Limit == 0)
return true;
return RecursionLevel < Limit;
}
void PrettyClassLayoutGraphicalDumper::dump(const PDBSymbolData &Symbol) {
assert(CurrentItem != nullptr);
DataMemberLayoutItem &Layout =
static_cast<DataMemberLayoutItem &>(*CurrentItem);
VariableDumper VarDumper(Printer);
VarDumper.start(Symbol, ClassOffsetZero);
if (Layout.hasUDTLayout() && shouldRecurse()) {
uint32_t ChildOffsetZero = ClassOffsetZero + Layout.getOffsetInParent();
Printer.Indent();
PrettyClassLayoutGraphicalDumper TypeDumper(Printer, RecursionLevel + 1,
ChildOffsetZero);
TypeDumper.start(Layout.getUDTLayout());
Printer.Unindent();
}
DumpedAnything = true;
}
void PrettyClassLayoutGraphicalDumper::dump(const PDBSymbolTypeVTable &Symbol) {
assert(CurrentItem != nullptr);
VariableDumper VarDumper(Printer);
VarDumper.start(Symbol, ClassOffsetZero);
DumpedAnything = true;
}
void PrettyClassLayoutGraphicalDumper::dump(const PDBSymbolTypeEnum &Symbol) {
DumpedAnything = true;
Printer.NewLine();
EnumDumper Dumper(Printer);
Dumper.start(Symbol);
}
void PrettyClassLayoutGraphicalDumper::dump(
const PDBSymbolTypeTypedef &Symbol) {
DumpedAnything = true;
Printer.NewLine();
TypedefDumper Dumper(Printer);
Dumper.start(Symbol);
}
void PrettyClassLayoutGraphicalDumper::dump(
const PDBSymbolTypeBuiltin &Symbol) {}
void PrettyClassLayoutGraphicalDumper::dump(const PDBSymbolTypeUDT &Symbol) {}
void PrettyClassLayoutGraphicalDumper::dump(const PDBSymbolFunc &Symbol) {
if (Printer.IsSymbolExcluded(Symbol.getName()))
return;
if (Symbol.isCompilerGenerated() && opts::pretty::ExcludeCompilerGenerated)
return;
if (Symbol.getLength() == 0 && !Symbol.isPureVirtual() &&
!Symbol.isIntroVirtualFunction())
return;
DumpedAnything = true;
Printer.NewLine();
FunctionDumper Dumper(Printer);
Dumper.start(Symbol, FunctionDumper::PointerType::None);
}