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// Copyright 2012 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "syzygy/block_graph/block_graph.h"
#include <limits>
#include "base/logging.h"
#include "base/strings/stringprintf.h"
// Pretty prints a BlockInfo to an ostream. This has to be outside of any
// namespaces so that operator<< is found properly.
std::ostream& operator<<(std::ostream& os, const block_graph::BlockInfo& bi) {
os << "Block(id=" << bi.block->id() << ", name=\"" << bi.block->name()
<< "\", size=" << bi.block->size();
if (bi.type != block_graph::BlockInfo::kNoAddress) {
os << ", address=";
switch (bi.type) {
case block_graph::BlockInfo::kAbsoluteAddress: {
os << bi.abs_addr;
break;
}
case block_graph::BlockInfo::kFileOffsetAddress: {
os << bi.file_addr;
break;
}
case block_graph::BlockInfo::kRelativeAddress: {
os << bi.rel_addr;
break;
}
default: break;
}
}
os << ")";
return os;
}
namespace block_graph {
namespace {
static_assert(BlockGraph::BLOCK_ATTRIBUTES_MAX_BIT < 32,
"Too many block attributes.");
// A list of printable names corresponding to image formats. This need to be
// kept in sync with the BlockGraph::ImageFormat enum!
const char* kImageFormat[] = {
"UNKNOWN_FORMAT", "PE_FORMAT", "COFF_FORMAT", "PE_IN_MEMORY_FORMAT",
};
static_assert(arraysize(kImageFormat) == BlockGraph::IMAGE_FORMAT_MAX,
"Image format not in sync.");
// A list of printable names corresponding to block types. This needs to
// be kept in sync with the BlockGraph::BlockType enum!
const char* kBlockType[] = {
"CODE_BLOCK", "DATA_BLOCK",
};
static_assert(arraysize(kBlockType) == BlockGraph::BLOCK_TYPE_MAX,
"Block type not in sync.");
// Shift all items in an offset -> item map by 'distance', provided the initial
// item offset was >= @p offset.
template<typename ItemType>
void ShiftOffsetItemMap(BlockGraph::Offset offset,
BlockGraph::Offset distance,
std::map<BlockGraph::Offset, ItemType>* items) {
DCHECK_GE(offset, 0);
DCHECK_NE(distance, 0);
DCHECK(items != NULL);
typedef std::map<BlockGraph::Offset, ItemType> ItemMap;
// Get iterators to all of the items that need changing.
std::vector<ItemMap::iterator> item_its;
ItemMap::iterator item_it = items->lower_bound(offset);
while (item_it != items->end()) {
item_its.push_back(item_it);
++item_it;
}
// Get the direction and bounds of the iteration. We need to walk through
// the iterators in a different order depending on if we're shifting left
// or right. This is to ensure that earlier shifts don't land on the values
// of later unshifted offsets.
SSIZE_T start = 0;
SSIZE_T stop = item_its.size();
int step = 1;
if (distance > 0) {
start = stop - 1;
stop = -1;
step = -1;
}
for (SSIZE_T i = start; i != stop; i += step) {
item_it = item_its[i];
items->insert(std::make_pair(item_it->first + distance,
item_it->second));
items->erase(item_it);
}
}
void ShiftReferences(BlockGraph::Block* block,
BlockGraph::Offset offset,
BlockGraph::Offset distance) {
// Make a copy of the reference map for simplicity.
BlockGraph::Block::ReferenceMap references = block->references();
// Start by removing all references that have moved.
BlockGraph::Block::ReferenceMap::const_iterator it =
references.lower_bound(offset);
for (; it != references.end(); ++it) {
if (it->first >= offset)
block->RemoveReference(it->first);
}
// Then patch up all existing references.
it = references.begin();
for (; it != references.end(); ++it) {
BlockGraph::Reference ref(it->second);
BlockGraph::Offset new_offset(it->first);
// If this is self-referential, fix the destination offset.
if (ref.referenced() == block && ref.offset() >= offset) {
ref = BlockGraph::Reference(ref.type(),
ref.size(),
ref.referenced(),
ref.offset() + distance,
ref.base() + distance);
}
// If its offset is past the change point, fix that.
if (it->first >= offset)
new_offset += distance;
// In many cases this'll be a noop.
// TODO(siggi): Optimize this.
block->SetReference(new_offset, ref);
}
}
// Shift all referrers beyond @p offset by @p distance.
void ShiftReferrers(BlockGraph::Block* self,
BlockGraph::Offset offset,
BlockGraph::Offset distance,
BlockGraph::Block::ReferrerSet* referrers) {
DCHECK_GE(offset, 0);
DCHECK_NE(distance, 0);
DCHECK(referrers != NULL);
typedef BlockGraph::Block::ReferrerSet ReferrerSet;
typedef BlockGraph::Reference Reference;
ReferrerSet::iterator ref_it = referrers->begin();
while (ref_it != referrers->end()) {
// We need to keep around the next iterator as 'ref_it' will be invalidated
// if we need to update the reference. (It will be deleted and then
// recreated.)
ReferrerSet::iterator next_ref_it = ref_it;
++next_ref_it;
BlockGraph::Block* ref_block = ref_it->first;
// Our own references will have been moved already.
if (ref_block != self) {
BlockGraph::Offset ref_offset = ref_it->second;
Reference ref;
bool ref_found = ref_block->GetReference(ref_offset, &ref);
DCHECK(ref_found);
// Shift the reference if need be.
if (ref.offset() >= offset) {
Reference new_ref(ref.type(),
ref.size(),
ref.referenced(),
ref.offset() + distance,
ref.base() + distance);
bool inserted = ref_block->SetReference(ref_offset, new_ref);
DCHECK(!inserted);
}
}
ref_it = next_ref_it;
}
}
const char* BlockAttributeToString(BlockGraph::BlockAttributeEnum attr) {
switch (attr) {
#define DEFINE_CASE(name) case BlockGraph::name: return #name;
BLOCK_ATTRIBUTE_ENUM(DEFINE_CASE)
#undef DEFINE_CASE
default:
NOTREACHED();
return NULL;
}
}
} // namespace
const char* BlockGraph::ImageFormatToString(ImageFormat format) {
DCHECK_LE(BlockGraph::PE_IMAGE, format);
DCHECK_GT(BlockGraph::IMAGE_FORMAT_MAX, format);
return kImageFormat[format];
}
std::string BlockGraph::BlockAttributesToString(BlockAttributes attrs) {
BlockAttributes attr = 1;
std::string s;
for (; attr < BLOCK_ATTRIBUTES_MAX; attr <<= 1) {
if (attr & attrs) {
if (!s.empty())
s.append("|");
s.append(BlockAttributeToString(static_cast<BlockAttributeEnum>(attr)));
}
}
return s;
}
const char* BlockGraph::BlockTypeToString(BlockGraph::BlockType type) {
DCHECK_LE(BlockGraph::CODE_BLOCK, type);
DCHECK_GT(BlockGraph::BLOCK_TYPE_MAX, type);
return kBlockType[type];
}
std::string BlockGraph::LabelAttributesToString(
BlockGraph::LabelAttributes label_attributes) {
static const char* kLabelAttributes[] = {
"Code", "DebugStart", "DebugEnd", "ScopeStart", "ScopeEnd",
"CallSite", "JumpTable", "CaseTable", "Data", "PublicSymbol" };
static_assert((1 << arraysize(kLabelAttributes)) == LABEL_ATTRIBUTES_MAX,
"Label attributes not in sync.");
std::string s;
for (size_t i = 0; i < arraysize(kLabelAttributes); ++i) {
if (label_attributes & (1 << i)) {
if (!s.empty())
s.append("|");
s.append(kLabelAttributes[i]);
}
}
return s;
}
const BlockGraph::SectionId BlockGraph::kInvalidSectionId = SIZE_MAX;
BlockGraph::BlockGraph()
: next_section_id_(0),
next_block_id_(0),
image_format_(UNKNOWN_IMAGE_FORMAT) {
}
BlockGraph::~BlockGraph() {
}
BlockGraph::Section* BlockGraph::AddSection(const base::StringPiece& name,
uint32_t characteristics) {
Section new_section(next_section_id_++, name, characteristics);
std::pair<SectionMap::iterator, bool> result = sections_.insert(
std::make_pair(new_section.id(), new_section));
DCHECK(result.second);
return &result.first->second;
}
BlockGraph::Section* BlockGraph::FindSection(const base::StringPiece& name) {
const BlockGraph* self = const_cast<const BlockGraph*>(this);
const BlockGraph::Section* section = self->FindSection(name);
return const_cast<BlockGraph::Section*>(section);
}
const BlockGraph::Section* BlockGraph::FindSection(
const base::StringPiece& name) const {
// This is a linear scan, but thankfully images generally do not have many
// sections and we do not create them very often. Fast lookup by index is
// more important. If this ever becomes an issue, we could keep around a
// second index by name.
SectionMap::const_iterator it = sections_.begin();
for (; it != sections_.end(); ++it) {
if (it->second.name() == name)
return &it->second;
}
return NULL;
}
BlockGraph::Section* BlockGraph::FindOrAddSection(const base::StringPiece& name,
uint32_t characteristics) {
Section* section = FindSection(name);
if (section) {
section->set_characteristic(characteristics);
return section;
}
return AddSection(name, characteristics);
}
bool BlockGraph::RemoveSection(Section* section) {
DCHECK(section != NULL);
SectionMap::iterator it(sections_.find(section->id()));
if (it == sections_.end() || &it->second != section)
return false;
sections_.erase(it);
return true;
}
bool BlockGraph::RemoveSectionById(SectionId id) {
SectionMap::iterator it(sections_.find(id));
if (it == sections_.end())
return false;
sections_.erase(it);
return true;
}
BlockGraph::Block* BlockGraph::AddBlock(BlockType type,
Size size,
const base::StringPiece& name) {
BlockId id = ++next_block_id_;
BlockMap::iterator it = blocks_.insert(
std::make_pair(id, Block(id, type, size, name, this))).first;
return &it->second;
}
BlockGraph::Block* BlockGraph::CopyBlock(Block* block,
const base::StringPiece& new_name) {
typedef BlockGraph::Reference Reference;
// Create the new block.
Block* new_block = AddBlock(block->type(), block->size(), new_name);
DCHECK(new_block != nullptr);
// Set the rest of the properties for the new block.
new_block->set_alignment(block->alignment());
new_block->set_alignment_offset(block->alignment_offset());
new_block->set_padding_before(block->padding_before());
new_block->set_compiland_name(block->compiland_name());
new_block->set_attributes(block->attributes());
new_block->set_section(block->section());
new_block->source_ranges() = block->source_ranges();
// Do not copy: name_, addr_.
// If block data exist, copy them.
if (block->data() != nullptr) {
// If |block| owns data then duplicate; otherwise just add reference.
if (block->owns_data()) {
uint8_t* data = new_block->CopyData(block->data_size(), block->data());
CHECK(data != nullptr);
} else {
new_block->SetData(block->data(), block->data_size());
}
}
// Copy self-references and external references.
for (const auto& ref_it : block->references()) {
const Reference& ref = ref_it.second;
if (ref.referenced() == block) { // Self-references.
Reference self_ref = Reference(ref.type(), ref.size(), new_block,
ref.offset(), ref.base());
new_block->SetReference(ref_it.first, self_ref);
} else {
new_block->SetReference(ref_it.first, ref_it.second);
}
}
// Copy labels.
for (const auto& label : block->labels())
new_block->SetLabel(label.first, label.second);
return new_block;
}
bool BlockGraph::RemoveBlock(Block* block) {
DCHECK(block != NULL);
BlockMap::iterator it(blocks_.find(block->id()));
if (it == blocks_.end() || &it->second != block)
return false;
return RemoveBlockByIterator(it);
}
bool BlockGraph::RemoveBlockById(BlockId id) {
BlockMap::iterator it(blocks_.find(id));
if (it == blocks_.end())
return false;
return RemoveBlockByIterator(it);
}
BlockGraph::Section* BlockGraph::GetSectionById(SectionId id) {
SectionMap::iterator it(sections_.find(id));
if (it == sections_.end())
return NULL;
return &it->second;
}
const BlockGraph::Section* BlockGraph::GetSectionById(SectionId id) const {
SectionMap::const_iterator it(sections_.find(id));
if (it == sections_.end())
return NULL;
return &it->second;
}
BlockGraph::Block* BlockGraph::GetBlockById(BlockId id) {
BlockMap::iterator it(blocks_.find(id));
if (it == blocks_.end())
return NULL;
return &it->second;
}
const BlockGraph::Block* BlockGraph::GetBlockById(BlockId id) const {
BlockMap::const_iterator it(blocks_.find(id));
if (it == blocks_.end())
return NULL;
return &it->second;
}
bool BlockGraph::RemoveBlockByIterator(BlockMap::iterator it) {
DCHECK(it != blocks_.end());
// Verify this block is fully disconnected.
if (it->second.referrers().size() > 0 || it->second.references().size() > 0)
return false;
blocks_.erase(it);
return true;
}
BlockGraph::AddressSpace::AddressSpace(BlockGraph* graph)
: graph_(graph) {
DCHECK(graph != NULL);
}
BlockGraph::Block* BlockGraph::AddressSpace::AddBlock(
BlockType type, RelativeAddress addr, Size size,
const base::StringPiece& name) {
if (size > 0) {
// First check to see that the range is clear.
AddressSpaceImpl::Range range(addr, size);
AddressSpaceImpl::RangeMap::iterator it =
address_space_.FindFirstIntersection(range);
if (it != address_space_.ranges().end())
return NULL;
}
BlockGraph::Block* block = graph_->AddBlock(type, size, name);
DCHECK(block != NULL);
bool inserted = InsertImpl(addr, block);
DCHECK(inserted);
return block;
}
bool BlockGraph::AddressSpace::ResizeBlock(Block* block, size_t size) {
DCHECK_NE(reinterpret_cast<Block*>(NULL), block);
// Determine if the block is in the address space. If so, this also finds its
// address.
BlockAddressMap::iterator block_it = block_addresses_.find(block);
if (block_it == block_addresses_.end())
return false;
// If the size isn't changing then we can return right away.
if (block->size() == size)
return true;
// If the original size is non-zero we expect it to be in the address-space.
AddressSpaceImpl::RangeMap::iterator range_it;
if (block->size() > 0) {
// Find the iterator associated with this blocks range.
AddressSpaceImpl::Range range(block_it->second, 1);
range_it = address_space_.FindContaining(range);
CHECK(range_it != address_space_.end());
// We expect the sizes to agree.
CHECK_EQ(block->size(), range_it->first.size());
// If the size is growing make sure we can grow it.
if (range_it->first.size() < size) {
// Get the next block.
AddressSpaceImpl::RangeMap::iterator range_next = range_it;
++range_next;
// If the current block extended to the new size conflicts with the old
// block then we can't do the resize.
if (range_next != address_space_.end() &&
range_it->first.start() + size > range_next->first.start()) {
return false;
}
}
// Remove the existing block from the address-space.
address_space_.Remove(range_it);
}
// Reinsert the block with its new range if its not empty. If the block is
// empty it won't be added back to the address space.
if (size > 0)
address_space_.Insert(Range(block_it->second, size), block, &range_it);
// Update the block with its new size.
block->set_size(size);
return true;
}
bool BlockGraph::AddressSpace::InsertBlock(RelativeAddress addr, Block* block) {
return InsertImpl(addr, block);
}
BlockGraph::Block* BlockGraph::AddressSpace::GetBlockByAddress(
RelativeAddress addr) const {
return GetContainingBlock(addr, 1);
}
BlockGraph::Block* BlockGraph::AddressSpace::GetContainingBlock(
RelativeAddress addr, Size size) const {
AddressSpaceImpl::Range range(addr, size);
AddressSpaceImpl::RangeMap::const_iterator it =
address_space_.FindContaining(range);
if (it == address_space_.ranges().end())
return NULL;
return it->second;
}
BlockGraph::Block* BlockGraph::AddressSpace::GetFirstIntersectingBlock(
RelativeAddress addr, Size size) {
AddressSpaceImpl::Range range(addr, size);
AddressSpaceImpl::RangeMap::iterator it =
address_space_.FindFirstIntersection(range);
if (it == address_space_.ranges().end())
return NULL;
return it->second;
}
BlockGraph::AddressSpace::RangeMapConstIterPair
BlockGraph::AddressSpace::GetIntersectingBlocks(RelativeAddress address,
Size size) const {
return address_space_.FindIntersecting(Range(address, size));
}
BlockGraph::AddressSpace::RangeMapIterPair
BlockGraph::AddressSpace::GetIntersectingBlocks(RelativeAddress address,
Size size) {
return address_space_.FindIntersecting(Range(address, size));
}
bool BlockGraph::AddressSpace::GetAddressOf(const Block* block,
RelativeAddress* addr) const {
DCHECK(block != NULL);
DCHECK(addr != NULL);
BlockAddressMap::const_iterator it(block_addresses_.find(block));
if (it == block_addresses_.end())
return false;
*addr = it->second;
return true;
}
bool BlockGraph::AddressSpace::InsertImpl(RelativeAddress addr, Block* block) {
// Only insert the block in the address-space if it has non-zero size.
if (block->size() > 0) {
Range range(addr, block->size());
bool inserted = address_space_.Insert(range, block);
if (!inserted)
return false;
}
bool inserted = block_addresses_.insert(std::make_pair(block, addr)).second;
DCHECK(inserted);
// Update the address stored in the block.
block->set_addr(addr);
return true;
}
bool BlockGraph::AddressSpace::ContainsBlock(const Block* block) {
DCHECK(block != NULL);
return block_addresses_.count(block) != 0;
}
BlockGraph::Block* BlockGraph::AddressSpace::MergeIntersectingBlocks(
const Range& range) {
typedef std::vector<std::pair<RelativeAddress, BlockGraph::Block*>>
BlockAddressVector;
// Find all the blocks that intersect the range, keep them and their
// addresses. Start by finding the first intersection, then iterate
// from there until we find a block that doesn't intersect with range.
AddressSpaceImpl::RangeMap::iterator address_start =
address_space_.FindFirstIntersection(range);
AddressSpaceImpl::RangeMap::iterator address_it(address_start);
BlockAddressVector intersecting;
for (; address_it != address_space_.ranges().end() &&
address_it->first.Intersects(range); ++address_it) {
intersecting.push_back(std::make_pair(address_it->first.start(),
address_it->second));
}
// Bail if the intersection doesn't cover at least two blocks.
if (intersecting.empty())
return NULL;
// In case of single-block intersection, we're done.
if (intersecting.size() == 1)
return intersecting[0].second;
DCHECK(!intersecting.empty());
// Calculate the start and end addresses of the new block.
BlockGraph::Block* first_block = intersecting[0].second;
BlockGraph::Block* last_block = intersecting[intersecting.size() - 1].second;
DCHECK(first_block != NULL && last_block != NULL);
RelativeAddress begin = std::min(range.start(), intersecting[0].first);
RelativeAddress end = std::max(range.start() + range.size(),
intersecting[intersecting.size() - 1].first + last_block->size());
DCHECK(begin <= range.start());
DCHECK(end >= range.start() + range.size());
base::StringPiece block_name = first_block->name();
BlockType block_type = first_block->type();
size_t section_id = first_block->section();
size_t alignment = first_block->alignment();
Offset alignment_offset = first_block->alignment_offset();
BlockAttributes attributes = 0;
// Some attributes are only propagated if they are present on *all* blocks
// in the range.
static const BlockAttributes kUniformAttributes =
GAP_BLOCK | PADDING_BLOCK | BUILT_BY_SYZYGY;
BlockAttributes uniform_attributes = kUniformAttributes;
BlockGraph::Block::SourceRanges source_ranges;
// Remove the found blocks from the address space, and make sure they're all
// of the same type and from the same section as the first block. Merge the
// data from all the blocks as we go along, as well as the attributes and
// source ranges.
std::vector<uint8_t> merged_data(end - begin);
bool have_data = false;
for (size_t i = 0; i < intersecting.size(); ++i) {
RelativeAddress addr = intersecting[i].first;
BlockGraph::Block* block = intersecting[i].second;
DCHECK_EQ(block_type, block->type());
DCHECK_EQ(section_id, block->section());
DCHECK_EQ(0U, block->padding_before());
if (block->data() != NULL) {
have_data = true;
memcpy(&merged_data.at(addr - begin), block->data(), block->data_size());
}
// Add any non-uniform attributes to the block, and keep track of the
// uniform attributes.
attributes |= block->attributes() & ~kUniformAttributes;
uniform_attributes &= block->attributes();
// Merge in the source ranges from each block.
BlockGraph::Offset block_offset = addr - begin;
BlockGraph::Block::SourceRanges::RangePairs::const_iterator src_it =
block->source_ranges().range_pairs().begin();
for (; src_it != block->source_ranges().range_pairs().end(); ++src_it) {
// The data range is wrt to the containing block, wo we have to translate
// each individual block's offset to an offset in the merged block.
BlockGraph::Offset merged_offset = block_offset + src_it->first.start();
bool pushed = source_ranges.Push(
BlockGraph::Block::DataRange(merged_offset, src_it->first.size()),
src_it->second);
DCHECK(pushed);
}
bool removed = address_space_.Remove(Range(addr, block->size()));
DCHECK(removed);
size_t num_removed = block_addresses_.erase(intersecting[i].second);
DCHECK_EQ(1U, num_removed);
}
// Create the new block.
BlockGraph::Block* new_block = AddBlock(block_type,
begin, end - begin,
block_name);
DCHECK(new_block != NULL);
// Set the rest of the properties for the new block.
new_block->source_ranges() = source_ranges;
new_block->set_section(section_id);
new_block->set_alignment(alignment);
new_block->set_alignment_offset(alignment_offset);
new_block->set_attributes(attributes | uniform_attributes);
if (have_data) {
uint8_t* data = new_block->CopyData(merged_data.size(), &merged_data.at(0));
if (data == NULL) {
LOG(ERROR) << "Unable to copy merged data";
return NULL;
}
}
// Now move all labels and references to the new block.
for (size_t i = 0; i < intersecting.size(); ++i) {
RelativeAddress addr = intersecting[i].first;
BlockGraph::Block* block = intersecting[i].second;
BlockGraph::Offset start_offset = addr - begin;
// If the destination block is not a code block, preserve the old block
// names as labels for debugging. We also need to make sure the label is
// not empty, as that is verboten.
if (block_type != BlockGraph::CODE_BLOCK && !block->name().empty()) {
new_block->SetLabel(start_offset,
block->name(),
BlockGraph::DATA_LABEL);
}
// Move labels.
BlockGraph::Block::LabelMap::const_iterator
label_it(block->labels().begin());
for (; label_it != block->labels().end(); ++label_it) {
new_block->SetLabel(start_offset + label_it->first,
label_it->second);
}
// Copy the reference map since we mutate the original.
BlockGraph::Block::ReferenceMap refs(block->references());
BlockGraph::Block::ReferenceMap::const_iterator ref_it(refs.begin());
for (; ref_it != refs.end(); ++ref_it) {
block->RemoveReference(ref_it->first);
new_block->SetReference(start_offset + ref_it->first, ref_it->second);
}
// Redirect all referrers to the new block.
block->TransferReferrers(start_offset,
new_block,
BlockGraph::Block::kTransferInternalReferences);
// Check that we've removed all references and
// referrers from the original block.
DCHECK(block->references().empty());
DCHECK(block->referrers().empty());
// Remove the original block.
bool removed = graph_->RemoveBlock(block);
DCHECK(removed);
}
return new_block;
}
bool BlockGraph::Section::set_name(const base::StringPiece& name) {
if (name == NULL)
return false;
if (name.empty())
return false;
name.CopyToString(&name_);
return true;
}
bool BlockGraph::Section::Save(core::OutArchive* out_archive) const {
DCHECK(out_archive != NULL);
return out_archive->Save(id_) && out_archive->Save(name_) &&
out_archive->Save(characteristics_);
}
bool BlockGraph::Section::Load(core::InArchive* in_archive) {
DCHECK(in_archive != NULL);
return in_archive->Load(&id_) && in_archive->Load(&name_) &&
in_archive->Load(&characteristics_);
}
std::string BlockGraph::Label::ToString() const {
return base::StringPrintf("%s (%s)",
name_.c_str(),
LabelAttributesToString(attributes_).c_str());
}
bool BlockGraph::Label::IsValid() const {
return AreValidAttributes(attributes_);
}
bool BlockGraph::Label::AreValidAttributes(LabelAttributes attributes) {
// A label needs to have at least one attribute.
if (attributes == 0)
return false;
// TODO(chrisha): Once we make the switch to VS2010 determine where call
// site labels may land. Are they at the beginning of the call
// instruction (in which case they may coincide with *_START_LABEL,
// *_END_LABEL and CODE_LABEL), or do they point at the address of the
// call (in which case they must be completely on their own)? For now, we
// simply ignore them entirely from consideration.
attributes &= ~CALL_SITE_LABEL;
// Public symbols can coincide with anything, so we can basically ignore
// them.
attributes &= ~PUBLIC_SYMBOL_LABEL;
// A code label can coincide with a debug and scope labels. (It can coincide
// with *_END_LABEL labels because of 1-byte instructions, like RET or INT.)
const LabelAttributes kCodeDebugScopeLabels =
CODE_LABEL | DEBUG_START_LABEL | DEBUG_END_LABEL | SCOPE_START_LABEL |
SCOPE_END_LABEL;
if ((attributes & CODE_LABEL) != 0 &&
(attributes & ~kCodeDebugScopeLabels) != 0) {
return false;
}
// A jump table must be paired with a data label. It may also be paired
// with a debug-end label if tail-call optimization has been applied by
// the compiler/linker.
const LabelAttributes kJumpDataLabelAttributes =
JUMP_TABLE_LABEL | DATA_LABEL;
if (attributes & JUMP_TABLE_LABEL) {
if ((attributes & kJumpDataLabelAttributes) != kJumpDataLabelAttributes)
return false;
// Filter out the debug-end label if present and check that nothing else
// is set.
attributes &= ~DEBUG_END_LABEL;
if ((attributes & ~kJumpDataLabelAttributes) != 0)
return false;
return true;
}
// A case table must be paired with a data label and nothing else.
const LabelAttributes kCaseDataLabelAttributes =
CASE_TABLE_LABEL | DATA_LABEL;
if (attributes & CASE_TABLE_LABEL) {
if ((attributes & kCaseDataLabelAttributes) != kCaseDataLabelAttributes)
return false;
if ((attributes & ~kCaseDataLabelAttributes) != 0)
return false;
return true;
}
// If there is no case or jump label, then a data label must be on its own.
if ((attributes & DATA_LABEL) != 0 && (attributes & ~DATA_LABEL) != 0)
return false;
return true;
}
BlockGraph::Block::Block(BlockGraph* block_graph)
: id_(0U),
type_(BlockGraph::CODE_BLOCK),
size_(0U),
alignment_(1U),
alignment_offset_(0),
padding_before_(0U),
name_(NULL),
compiland_name_(NULL),
addr_(RelativeAddress::kInvalidAddress),
block_graph_(block_graph),
section_(kInvalidSectionId),
attributes_(0U),
owns_data_(false),
data_(NULL),
data_size_(0U) {
DCHECK(block_graph != NULL);
}
BlockGraph::Block::Block(BlockId id,
BlockType type,
Size size,
const base::StringPiece& name,
BlockGraph* block_graph)
: id_(id),
type_(type),
size_(size),
alignment_(1U),
alignment_offset_(0),
padding_before_(0U),
name_(NULL),
compiland_name_(NULL),
addr_(RelativeAddress::kInvalidAddress),
block_graph_(block_graph),
section_(kInvalidSectionId),
attributes_(0U),
owns_data_(false),
data_(NULL),
data_size_(0U) {
DCHECK(block_graph != NULL);
set_name(name);
}
BlockGraph::Block::~Block() {
DCHECK(block_graph_ != NULL);
if (owns_data_)
delete [] data_;
}
void BlockGraph::Block::set_name(const base::StringPiece& name) {
DCHECK(block_graph_ != NULL);
const std::string& interned_name =
block_graph_->string_table().InternString(name);
name_ = &interned_name;
}
const std::string& BlockGraph::Block::compiland_name() const {
DCHECK(block_graph_ != NULL);
if (compiland_name_ == NULL)
return block_graph_->string_table().InternString("");
return *compiland_name_;
}
void BlockGraph::Block::set_compiland_name(const base::StringPiece& name) {
DCHECK(block_graph_ != NULL);
const std::string& interned_name =
block_graph_->string_table().InternString(name);
compiland_name_ = &interned_name;
}
uint8_t* BlockGraph::Block::AllocateRawData(size_t data_size) {
DCHECK_GT(data_size, 0u);
DCHECK_LE(data_size, size_);
uint8_t* new_data = new uint8_t[data_size];
if (!new_data)
return NULL;
if (owns_data()) {
DCHECK(data_ != NULL);
delete [] data_;
}
data_ = new_data;
data_size_ = data_size;
owns_data_ = true;
return new_data;
}
void BlockGraph::Block::InsertData(Offset offset,
Size size,
bool always_allocate_data) {
DCHECK_GE(offset, 0);
DCHECK_LE(offset, static_cast<Offset>(size_));
if (size > 0) {
// Patch up the block.
size_ += size;
ShiftOffsetItemMap(offset, size, &labels_);
ShiftReferences(this, offset, size);
ShiftReferrers(this, offset, size, &referrers_);
source_ranges_.InsertUnmappedRange(DataRange(offset, size));
// Does this affect already allocated data?
if (static_cast<Size>(offset) < data_size_) {
// Reallocate, shift the old data to the end, and zero out the new data.
size_t bytes_to_shift = data_size_ - offset;
ResizeData(data_size_ + size);
uint8_t* new_data = GetMutableData();
memmove(new_data + offset + size, new_data + offset, bytes_to_shift);
memset(new_data + offset, 0, size);
}
}
// If we've been asked to, at least make sure that the data is allocated.
if (always_allocate_data && data_size_ < offset + size)
ResizeData(offset + size);
return;
}
bool BlockGraph::Block::RemoveData(Offset offset, Size size) {
DCHECK_GE(offset, 0);
DCHECK_LE(offset, static_cast<Offset>(size_));
if (size == 0)
return true;
// Ensure there are no labels in this range.
if (labels_.lower_bound(offset) != labels_.lower_bound(offset + size))
return false;
// Ensure that there are no references intersecting this range.
ReferenceMap::const_iterator refc_it = references_.begin();
for (; refc_it != references_.end(); ++refc_it) {
if (refc_it->first >= static_cast<Offset>(offset + size))
break;
if (static_cast<Offset>(refc_it->first + refc_it->second.size()) > offset)
return false;
}
// Ensure there are no referrers pointing to the data we want to remove.
ReferrerSet::const_iterator refr_it = referrers_.begin();
for (; refr_it != referrers_.end(); ++refr_it) {
Reference ref;
if (!refr_it->first->GetReference(refr_it->second, &ref)) {
LOG(ERROR) << "Unable to get reference from referrer.";
return false;
}
if (ref.offset() < static_cast<Offset>(offset + size) &&
static_cast<Offset>(ref.offset() + ref.size()) > offset) {
return false;
}
}
// Patch up the block.
size_ -= size;
ShiftOffsetItemMap(offset + size, -static_cast<int>(size), &labels_);
ShiftReferences(this, offset + size, -static_cast<int>(size));
ShiftReferrers(this, offset + size, -static_cast<int>(size), &referrers_);
source_ranges_.RemoveMappedRange(DataRange(offset, size));
// Does this affect already allocated data?
if (static_cast<Size>(offset) < data_size_) {
size_t new_data_size = data_size_ - size;
// Is there data beyond the section to delete?
if (static_cast<Size>(offset + size) < data_size_) {
// Shift tail data to left.
uint8_t* data = GetMutableData();
size_t bytes_to_shift = data_size_ - offset - size;
size_t old_data_size = data_size_;
memmove(data + new_data_size - bytes_to_shift,
data + old_data_size - bytes_to_shift,
bytes_to_shift);
} else {
new_data_size = offset;
}
ResizeData(new_data_size);
}
return true;
}
bool BlockGraph::Block::InsertOrRemoveData(Offset offset,
Size current_size,
Size new_size,
bool always_allocate_data) {
DCHECK_GE(offset, 0);
DCHECK_LE(offset, static_cast<Offset>(size_));
// If we're growing use InsertData.
if (new_size > current_size) {
Offset insert_offset = offset + current_size;
Size insert_size = new_size - current_size;
InsertData(insert_offset, insert_size, always_allocate_data);
return true;
}
// If we're shrinking we'll need to use RemoveData.
if (new_size < current_size) {
Offset remove_offset = offset + new_size;
Size remove_size = current_size - new_size;
if (!RemoveData(remove_offset, remove_size))
return false;
// We fall through so that 'always_allocate_data' can be respected.
}
// If we've been asked to, at least make sure that the data is allocated.
if (always_allocate_data && data_size_ < offset + new_size)
ResizeData(offset + new_size);
return true;
}
void BlockGraph::Block::SetData(const uint8_t* data, size_t data_size) {
DCHECK((data_size == 0 && data == NULL) ||
(data_size != 0 && data != NULL));
DCHECK(data_size <= size_);
if (owns_data_)
delete [] data_;
owns_data_ = false;
data_ = data;
data_size_ = data_size;
}
uint8_t* BlockGraph::Block::AllocateData(size_t size) {
uint8_t* new_data = AllocateRawData(size);
if (new_data == NULL)
return NULL;
::memset(new_data, 0, size);
return new_data;
}
uint8_t* BlockGraph::Block::CopyData(size_t size, const void* data) {
uint8_t* new_data = AllocateRawData(size);
if (new_data == NULL)
return NULL;
memcpy(new_data, data, size);
return new_data;
}
const uint8_t* BlockGraph::Block::ResizeData(size_t new_size) {
if (new_size == data_size_)
return data_;
if (!owns_data() && new_size < data_size_) {
// Not in our ownership and shrinking. We only need to adjust our length.
data_size_ = new_size;
} else {
// Either our own data, or it's growing (or both).
uint8_t* new_data = NULL;
// If the new size is non-zero we need to reallocate.
if (new_size > 0) {
new_data = new uint8_t[new_size];
CHECK(new_data);
// Copy the (head of the) old data.
memcpy(new_data, data_, std::min(data_size_, new_size));
if (new_size > data_size_) {
// Zero the tail.
memset(new_data + data_size_, 0, new_size - data_size_);
}
}
if (owns_data())
delete [] data_;
owns_data_ = true;
data_ = new_data;
data_size_ = new_size;
}
return data_;
}
uint8_t* BlockGraph::Block::GetMutableData() {
DCHECK_NE(0U, data_size_);
DCHECK(data_ != NULL);
// Make a copy if we don't already own the data.
if (!owns_data()) {
uint8_t* new_data = new uint8_t[data_size_];
if (new_data == NULL)
return NULL;
memcpy(new_data, data_, data_size_);
data_ = new_data;
owns_data_ = true;
}
DCHECK(owns_data_);
return const_cast<uint8_t*>(data_);
}
bool BlockGraph::Block::HasExternalReferrers() const {
ReferrerSet::const_iterator it = referrers().begin();
for (; it != referrers().end(); ++it) {
if (it->first != this)
return true;
}
return false;
}
bool BlockGraph::Block::SetReference(Offset offset, const Reference& ref) {
DCHECK(ref.referenced() != NULL);
// Non-code blocks can be referred to by pointers that lie outside of their
// extent (due to loop induction, arrays indexed with an implicit offset,
// etc). Code blocks can not be referred to in this manner, because references
// in code blocks must be places where the flow of execution actually lands.
if (ref.referenced()->type() == CODE_BLOCK) {
DCHECK(ref.offset() >= 0 &&
static_cast<size_t>(ref.offset()) <= ref.referenced()->size());
DCHECK(offset + ref.size() <= size());
}
#if defined(DEBUG) || !defined(NDEBUG)
{
// NOTE: It might be worthwhile making SetReference return true on success,
// and false on failure as it is possible for references to conflict.
// For now we simply check for conflicts in debug builds and die an
// unglorious death if we find any.
if (!ref.IsValid())
NOTREACHED() << "Trying to insert invalid reference.";
// Examine references before us that could possibly conflict with us.
Offset offset_begin = offset - Reference::kMaximumSize + 1;
ReferenceMap::const_iterator it =
references_.lower_bound(offset_begin);
for (; it != references_.end() && it->first < offset; ++it) {
if (static_cast<Offset>(it->first + it->second.size()) > offset)
NOTREACHED() << "Trying to insert conflicting reference.";
}
// Skip the reference at the same offset if there is one. This reference
// will be replaced by the new one.
if (it != references_.end() && it->first == offset)
++it;
// This is the first reference after our offset. Check to see if it lands
// within the range we want to occupy.
if (it != references_.end() &&
it->first < static_cast<Offset>(offset + ref.size())) {
NOTREACHED() << "Trying to insert conflicting reference.";
}
}
#endif
// Did we have an earlier reference at this location?
ReferenceMap::iterator it(references_.find(offset));
bool inserted = false;
if (it != references_.end()) {
// Erase the back reference.
BlockGraph::Block* referenced = it->second.referenced();
Referrer referrer(this, offset);
size_t removed = referenced->referrers_.erase(referrer);
DCHECK_EQ(1U, removed);
// Lastly switch the reference.
it->second = ref;
} else {
// It's a new reference, insert it.
inserted = references_.insert(std::make_pair(offset, ref)).second;
DCHECK(inserted);
}
// Record the back-reference.
ref.referenced()->referrers_.insert(std::make_pair(this, offset));
return inserted;
}
bool BlockGraph::Block::GetReference(Offset offset,
Reference* reference) const {
DCHECK(reference != NULL);
ReferenceMap::const_iterator it(references_.find(offset));
if (it == references_.end())
return false;
*reference = it->second;
return true;
}
bool BlockGraph::Block::RemoveReference(Offset offset) {
// Do we have reference at this location?
ReferenceMap::iterator it(references_.find(offset));
if (it == references_.end())
return false;
BlockGraph::Block* referenced = it->second.referenced();
Referrer referrer(this, offset);
size_t removed = referenced->referrers_.erase(referrer);
DCHECK_EQ(1U, removed);
references_.erase(it);
return true;
}
bool BlockGraph::Block::RemoveAllReferences() {
ReferenceMap::iterator it = references_.begin();
while (it != references_.end()) {
ReferenceMap::iterator to_remove = it;
++it;
// TODO(rogerm): As an optimization, we don't need to drop intra-block
// references when disconnecting from the block_graph. Consider having
// BlockGraph::RemoveBlockByIterator() check that the block has no
// external referrers before calling this function and erasing the
// block.
// Unregister this reference from the referred block then erase it.
BlockGraph::Block* referenced = to_remove->second.referenced();
Referrer referrer(this, to_remove->first);
size_t removed = referenced->referrers_.erase(referrer);
DCHECK_EQ(1U, removed);
references_.erase(to_remove);
}
return true;
}
bool BlockGraph::Block::SetLabel(Offset offset, const Label& label) {
DCHECK_LE(0, offset);
DCHECK_LE(static_cast<size_t>(offset), size_);
VLOG(2) << name() << ": adding "
<< LabelAttributesToString(label.attributes()) << " label '"
<< label.name() << "' at offset " << offset << ".";
// Try inserting the label into the label map.
std::pair<LabelMap::iterator, bool> result(
labels_.insert(std::make_pair(offset, label)));
// If it was freshly inserted then we're done.
if (result.second)
return true;
return false;
}
bool BlockGraph::Block::GetLabel(Offset offset, Label* label) const {
DCHECK(offset >= 0 && static_cast<size_t>(offset) <= size_);
DCHECK(label != NULL);
LabelMap::const_iterator it = labels_.find(offset);
if (it == labels_.end())
return false;
*label = it->second;
return true;
}
bool BlockGraph::Block::RemoveLabel(Offset offset) {
DCHECK(offset >= 0 && static_cast<size_t>(offset) <= size_);
return labels_.erase(offset) == 1;
}
bool BlockGraph::Block::HasLabel(Offset offset) const {
DCHECK(offset >= 0 && static_cast<size_t>(offset) <= size_);
return labels_.find(offset) != labels_.end();
}
bool BlockGraph::Block::TransferReferrers(Offset offset,
Block* new_block, TransferReferrersFlags flags) {
// Redirect all referrers to the new block, we copy the referrer set
// because it is otherwise mutated during iteration.
BlockGraph::Block::ReferrerSet referrers = referrers_;
BlockGraph::Block::ReferrerSet::const_iterator referrer_it(referrers.begin());
for (; referrer_it != referrers.end(); ++referrer_it) {
// Get the original reference.
BlockGraph::Block::Referrer referrer = *referrer_it;
BlockGraph::Block::ReferenceMap::const_iterator found_ref(
referrer.first->references().find(referrer.second));
DCHECK(found_ref != referrer.first->references().end());
BlockGraph::Reference ref(found_ref->second);
if ((flags & kSkipInternalReferences) != 0 && referrer.first == this)
continue;
Offset new_offset = ref.offset() + offset;
Offset new_base = ref.base() + offset;
// Same thing as in SetReferrer, references to non-code blocks may lie
// outside the extent of the block.
if (type_ == CODE_BLOCK) {
if (new_offset < 0 ||
static_cast<size_t>(new_offset) > new_block->size()) {
LOG(ERROR) << "Transferred reference lies outside of code block.";
return false;
}
}
// Redirect the reference to the new block with the adjusted offset.
BlockGraph::Reference new_ref(ref.type(),
ref.size(),
new_block,
new_offset,
new_base);
referrer.first->SetReference(referrer.second, new_ref);
}
return true;
}
// Returns true if this block contains the given range of bytes.
bool BlockGraph::Block::Contains(RelativeAddress address, size_t size) const {
return (address >= addr_ && address + size <= addr_ + size_);
}
bool BlockGraph::Reference::IsValid() const {
// We can't reference a NULL block.
if (referenced_ == NULL)
return false;
// First see if the base address is valid for the referenced block. Base
// addresses must track an existing position in the block, between zero
// (beginning of the block), and one past the last byte (end of the
// block). These are the same offsets that are valid for InsertData(),
// such that inserting data at that position or before would shift the
// reference along. Hence, an end reference (one past the size of the
// block) would always be shifted regardless of the point of insertion;
// conversely, a reference to address zero would never move.
if (base_ < 0 || static_cast<size_t>(base_) > referenced_->size())
return false;
if (!IsValidTypeSize(type_, size_))
return false;
return true;
}
bool BlockGraph::Reference::IsValidTypeSize(ReferenceType type, Size size) {
switch (type & ~RELOC_REF_BIT) {
// We see 8- and 32-bit relative JMPs.
case PC_RELATIVE_REF:
return size == 1 || size == 4;
// These types are all pointer sized.
case ABSOLUTE_REF:
case RELATIVE_REF:
case FILE_OFFSET_REF:
return size == 4;
case SECTION_REF:
return size == 2;
case SECTION_OFFSET_REF:
return size == 1 || size == 4;
default:
NOTREACHED() << "Unknown ReferenceType.";
}
return false;
}
} // namespace block_graph