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Diffstat (limited to 'toolkit/crashreporter/google-breakpad/src/common/test_assembler.cc')
| -rw-r--r-- | toolkit/crashreporter/google-breakpad/src/common/test_assembler.cc | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/toolkit/crashreporter/google-breakpad/src/common/test_assembler.cc b/toolkit/crashreporter/google-breakpad/src/common/test_assembler.cc new file mode 100644 index 0000000000..1e783b45c5 --- /dev/null +++ b/toolkit/crashreporter/google-breakpad/src/common/test_assembler.cc @@ -0,0 +1,359 @@ +// Copyright (c) 2010, Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +// Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com> + +// test_assembler.cc: Implementation of google_breakpad::TestAssembler. +// See test_assembler.h for details. + +#include "common/test_assembler.h" + +#include <assert.h> +#include <stdio.h> + +#include <iterator> + +namespace google_breakpad { +namespace test_assembler { + +using std::back_insert_iterator; + +Label::Label() : value_(new Binding()) { } +Label::Label(uint64_t value) : value_(new Binding(value)) { } +Label::Label(const Label &label) { + value_ = label.value_; + value_->Acquire(); +} +Label::~Label() { + if (value_->Release()) delete value_; +} + +Label &Label::operator=(uint64_t value) { + value_->Set(NULL, value); + return *this; +} + +Label &Label::operator=(const Label &label) { + value_->Set(label.value_, 0); + return *this; +} + +Label Label::operator+(uint64_t addend) const { + Label l; + l.value_->Set(this->value_, addend); + return l; +} + +Label Label::operator-(uint64_t subtrahend) const { + Label l; + l.value_->Set(this->value_, -subtrahend); + return l; +} + +// When NDEBUG is #defined, assert doesn't evaluate its argument. This +// means you can't simply use assert to check the return value of a +// function with necessary side effects. +// +// ALWAYS_EVALUATE_AND_ASSERT(x) evaluates x regardless of whether +// NDEBUG is #defined; when NDEBUG is not #defined, it further asserts +// that x is true. +#ifdef NDEBUG +#define ALWAYS_EVALUATE_AND_ASSERT(x) x +#else +#define ALWAYS_EVALUATE_AND_ASSERT(x) assert(x) +#endif + +uint64_t Label::operator-(const Label &label) const { + uint64_t offset; + ALWAYS_EVALUATE_AND_ASSERT(IsKnownOffsetFrom(label, &offset)); + return offset; +} + +uint64_t Label::Value() const { + uint64_t v = 0; + ALWAYS_EVALUATE_AND_ASSERT(IsKnownConstant(&v)); + return v; +}; + +bool Label::IsKnownConstant(uint64_t *value_p) const { + Binding *base; + uint64_t addend; + value_->Get(&base, &addend); + if (base != NULL) return false; + if (value_p) *value_p = addend; + return true; +} + +bool Label::IsKnownOffsetFrom(const Label &label, uint64_t *offset_p) const +{ + Binding *label_base, *this_base; + uint64_t label_addend, this_addend; + label.value_->Get(&label_base, &label_addend); + value_->Get(&this_base, &this_addend); + // If this and label are related, Get will find their final + // common ancestor, regardless of how indirect the relation is. This + // comparison also handles the constant vs. constant case. + if (this_base != label_base) return false; + if (offset_p) *offset_p = this_addend - label_addend; + return true; +} + +Label::Binding::Binding() : base_(this), addend_(), reference_count_(1) { } + +Label::Binding::Binding(uint64_t addend) + : base_(NULL), addend_(addend), reference_count_(1) { } + +Label::Binding::~Binding() { + assert(reference_count_ == 0); + if (base_ && base_ != this && base_->Release()) + delete base_; +} + +void Label::Binding::Set(Binding *binding, uint64_t addend) { + if (!base_ && !binding) { + // We're equating two constants. This could be okay. + assert(addend_ == addend); + } else if (!base_) { + // We are a known constant, but BINDING may not be, so turn the + // tables and try to set BINDING's value instead. + binding->Set(NULL, addend_ - addend); + } else { + if (binding) { + // Find binding's final value. Since the final value is always either + // completely unconstrained or a constant, never a reference to + // another variable (otherwise, it wouldn't be final), this + // guarantees we won't create cycles here, even for code like this: + // l = m, m = n, n = l; + uint64_t binding_addend; + binding->Get(&binding, &binding_addend); + addend += binding_addend; + } + + // It seems likely that setting a binding to itself is a bug + // (although I can imagine this might turn out to be helpful to + // permit). + assert(binding != this); + + if (base_ != this) { + // Set the other bindings on our chain as well. Note that this + // is sufficient even though binding relationships form trees: + // All binding operations traverse their chains to the end, and + // all bindings related to us share some tail of our chain, so + // they will see the changes we make here. + base_->Set(binding, addend - addend_); + // We're not going to use base_ any more. + if (base_->Release()) delete base_; + } + + // Adopt BINDING as our base. Note that it should be correct to + // acquire here, after the release above, even though the usual + // reference-counting rules call for acquiring first, and then + // releasing: the self-reference assertion above should have + // complained if BINDING were 'this' or anywhere along our chain, + // so we didn't release BINDING. + if (binding) binding->Acquire(); + base_ = binding; + addend_ = addend; + } +} + +void Label::Binding::Get(Binding **base, uint64_t *addend) { + if (base_ && base_ != this) { + // Recurse to find the end of our reference chain (the root of our + // tree), and then rewrite every binding along the chain to refer + // to it directly, adjusting addends appropriately. (This is why + // this member function isn't this-const.) + Binding *final_base; + uint64_t final_addend; + base_->Get(&final_base, &final_addend); + if (final_base) final_base->Acquire(); + if (base_->Release()) delete base_; + base_ = final_base; + addend_ += final_addend; + } + *base = base_; + *addend = addend_; +} + +template<typename Inserter> +static inline void InsertEndian(test_assembler::Endianness endianness, + size_t size, uint64_t number, Inserter dest) { + assert(size > 0); + if (endianness == kLittleEndian) { + for (size_t i = 0; i < size; i++) { + *dest++ = (char) (number & 0xff); + number >>= 8; + } + } else { + assert(endianness == kBigEndian); + // The loop condition is odd, but it's correct for size_t. + for (size_t i = size - 1; i < size; i--) + *dest++ = (char) ((number >> (i * 8)) & 0xff); + } +} + +Section &Section::Append(Endianness endianness, size_t size, uint64_t number) { + InsertEndian(endianness, size, number, + back_insert_iterator<string>(contents_)); + return *this; +} + +Section &Section::Append(Endianness endianness, size_t size, + const Label &label) { + // If this label's value is known, there's no reason to waste an + // entry in references_ on it. + uint64_t value; + if (label.IsKnownConstant(&value)) + return Append(endianness, size, value); + + // This will get caught when the references are resolved, but it's + // nicer to find out earlier. + assert(endianness != kUnsetEndian); + + references_.push_back(Reference(contents_.size(), endianness, size, label)); + contents_.append(size, 0); + return *this; +} + +#define ENDIANNESS_L kLittleEndian +#define ENDIANNESS_B kBigEndian +#define ENDIANNESS(e) ENDIANNESS_ ## e + +#define DEFINE_SHORT_APPEND_NUMBER_ENDIAN(e, bits) \ + Section &Section::e ## bits(uint ## bits ## _t v) { \ + InsertEndian(ENDIANNESS(e), bits / 8, v, \ + back_insert_iterator<string>(contents_)); \ + return *this; \ + } + +#define DEFINE_SHORT_APPEND_LABEL_ENDIAN(e, bits) \ + Section &Section::e ## bits(const Label &v) { \ + return Append(ENDIANNESS(e), bits / 8, v); \ + } + +// Define L16, B32, and friends. +#define DEFINE_SHORT_APPEND_ENDIAN(e, bits) \ + DEFINE_SHORT_APPEND_NUMBER_ENDIAN(e, bits) \ + DEFINE_SHORT_APPEND_LABEL_ENDIAN(e, bits) + +DEFINE_SHORT_APPEND_LABEL_ENDIAN(L, 8); +DEFINE_SHORT_APPEND_LABEL_ENDIAN(B, 8); +DEFINE_SHORT_APPEND_ENDIAN(L, 16); +DEFINE_SHORT_APPEND_ENDIAN(L, 32); +DEFINE_SHORT_APPEND_ENDIAN(L, 64); +DEFINE_SHORT_APPEND_ENDIAN(B, 16); +DEFINE_SHORT_APPEND_ENDIAN(B, 32); +DEFINE_SHORT_APPEND_ENDIAN(B, 64); + +#define DEFINE_SHORT_APPEND_NUMBER_DEFAULT(bits) \ + Section &Section::D ## bits(uint ## bits ## _t v) { \ + InsertEndian(endianness_, bits / 8, v, \ + back_insert_iterator<string>(contents_)); \ + return *this; \ + } +#define DEFINE_SHORT_APPEND_LABEL_DEFAULT(bits) \ + Section &Section::D ## bits(const Label &v) { \ + return Append(endianness_, bits / 8, v); \ + } +#define DEFINE_SHORT_APPEND_DEFAULT(bits) \ + DEFINE_SHORT_APPEND_NUMBER_DEFAULT(bits) \ + DEFINE_SHORT_APPEND_LABEL_DEFAULT(bits) + +DEFINE_SHORT_APPEND_LABEL_DEFAULT(8) +DEFINE_SHORT_APPEND_DEFAULT(16); +DEFINE_SHORT_APPEND_DEFAULT(32); +DEFINE_SHORT_APPEND_DEFAULT(64); + +Section &Section::Append(const Section §ion) { + size_t base = contents_.size(); + contents_.append(section.contents_); + for (vector<Reference>::const_iterator it = section.references_.begin(); + it != section.references_.end(); it++) + references_.push_back(Reference(base + it->offset, it->endianness, + it->size, it->label)); + return *this; +} + +Section &Section::LEB128(long long value) { + while (value < -0x40 || 0x3f < value) { + contents_ += (value & 0x7f) | 0x80; + if (value < 0) + value = (value >> 7) | ~(((unsigned long long) -1) >> 7); + else + value = (value >> 7); + } + contents_ += value & 0x7f; + return *this; +} + +Section &Section::ULEB128(uint64_t value) { + while (value > 0x7f) { + contents_ += (value & 0x7f) | 0x80; + value = (value >> 7); + } + contents_ += value; + return *this; +} + +Section &Section::Align(size_t alignment, uint8_t pad_byte) { + // ALIGNMENT must be a power of two. + assert(((alignment - 1) & alignment) == 0); + size_t new_size = (contents_.size() + alignment - 1) & ~(alignment - 1); + contents_.append(new_size - contents_.size(), pad_byte); + assert((contents_.size() & (alignment - 1)) == 0); + return *this; +} + +void Section::Clear() { + contents_.clear(); + references_.clear(); +} + +bool Section::GetContents(string *contents) { + // For each label reference, find the label's value, and patch it into + // the section's contents. + for (size_t i = 0; i < references_.size(); i++) { + Reference &r = references_[i]; + uint64_t value; + if (!r.label.IsKnownConstant(&value)) { + fprintf(stderr, "Undefined label #%zu at offset 0x%zx\n", i, r.offset); + return false; + } + assert(r.offset < contents_.size()); + assert(contents_.size() - r.offset >= r.size); + InsertEndian(r.endianness, r.size, value, contents_.begin() + r.offset); + } + contents->clear(); + std::swap(contents_, *contents); + references_.clear(); + return true; +} + +} // namespace test_assembler +} // namespace google_breakpad |