Breakpad test support: Move test_assembler.{h,cc} from src/processor to src/common.

The google_breakpad::TestAssembler classes are used in both the processor's
and the Linux dumper's test suites, and will soon be used in the Mac
dumper's tests as well. This patch moves their source files from
src/processor to src/common.

a=jimblandy, r=thestig


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@574 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 357 insertions, 0 deletions

diff --git a/src/common/test_assembler.cc b/src/common/test_assembler.cc
new file mode 100644
index 00000000..3fd7cad0
--- /dev/null
+++ b/src/common/test_assembler.cc
@@ -0,0 +1,357 @@
+// 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 <cassert>
+#include <cstdio>
+#include <iterator>
+
+#include "common/test_assembler.h"
+
+namespace google_breakpad {
+namespace TestAssembler {
+
+using std::back_insert_iterator;
+
+Label::Label() : value_(new Binding()) { }
+Label::Label(u_int64_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=(u_int64_t value) {
+  value_->Set(NULL, value);
+  return *this;
+}
+
+Label &Label::operator=(const Label &label) {
+  value_->Set(label.value_, 0);
+  return *this;
+}
+
+Label Label::operator+(u_int64_t addend) const {
+  Label l;
+  l.value_->Set(this->value_, addend);
+  return l;
+}
+
+Label Label::operator-(u_int64_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
+
+u_int64_t Label::operator-(const Label &label) const {
+  u_int64_t offset;
+  ALWAYS_EVALUATE_AND_ASSERT(IsKnownOffsetFrom(label, &offset));
+  return offset;
+}
+
+u_int64_t Label::Value() const {
+  u_int64_t v;
+  ALWAYS_EVALUATE_AND_ASSERT(IsKnownConstant(&v));
+  return v;
+};
+
+bool Label::IsKnownConstant(u_int64_t *value_p) const {
+  Binding *base;
+  u_int64_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, u_int64_t *offset_p) const
+{
+  Binding *label_base, *this_base;
+  u_int64_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(u_int64_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, u_int64_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;
+      u_int64_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, u_int64_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;
+    u_int64_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(TestAssembler::Endianness endianness,
+                                size_t size, u_int64_t number, Inserter dest) {
+  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, u_int64_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.
+  u_int64_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(u_int ## 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(u_int ## 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 &section) {
+  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(u_int64_t value) {
+  while (value > 0x7f) {
+    contents_ += (value & 0x7f) | 0x80;
+    value = (value >> 7);
+  }
+  contents_ += value;
+  return *this;
+}
+
+Section &Section::Align(size_t alignment, u_int8_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];
+    u_int64_t value;
+    if (!r.label.IsKnownConstant(&value)) {
+      fprintf(stderr, "Undefined label #%d at offset 0x%x\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 TestAssembler
+} // namespace google_breakpad