Breakpad: Add minidump processor support for DWARF Call Frame Information.

Add a CFIFrameInfo class (named for symmetry with WindowsFrameInfo) to
represent the set of STACK CFI rules in effect at a given instruction,
and apply them to a set of register values. Provide a SimpleCFIWalker
class template, to allow the essential CFI code to be shared amongst
the different architectures.

Teach BasicSourceLineResolver to partially parse 'STACK CFI' records,
and produce the set of rules in effect at a given instruction on
demand, by combining the initial rule set and the appropriate rule
deltas in a CFIFrameInfo object.

Adapt StackwalkerX86 and StackFrameX86 to retrieve, store, and apply
CFI stack walking information.

Add validity flags for all the general-purpose registers to
StackFrameX86::ContextValidity.

a=jimblandy, r=mmentovai


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@549 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/processor/cfi_frame_info.cc

@@ -0,0 +1,157 @@
+// 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>
+
+// cfi_frame_info.cc: Implementation of CFIFrameInfo class.
+// See cfi_frame_info.h for details.
+
+#include <cstring>
+
+#include "processor/cfi_frame_info.h"
+#include "processor/postfix_evaluator-inl.h"
+#include "processor/scoped_ptr.h"
+
+namespace google_breakpad {
+
+template<typename V>
+bool CFIFrameInfo::FindCallerRegs(const RegisterValueMap<V> &registers,
+                                  const MemoryRegion &memory,
+                                  RegisterValueMap<V> *caller_registers) const {
+  // If there are not rules for both .ra and .cfa in effect at this address,
+  // don't use this CFI data for stack walking.
+  if (cfa_rule_.empty() || ra_rule_.empty())
+    return false;
+
+  RegisterValueMap<V> working;
+  PostfixEvaluator<V> evaluator(&working, &memory);
+
+  caller_registers->clear();
+
+  // First, compute the CFA.
+  V cfa;
+  working = registers;
+  if (!evaluator.EvaluateForValue(cfa_rule_, &cfa))
+    return false;
+
+  // Then, compute the return address.
+  V ra;
+  working = registers;
+  working[".cfa"] = cfa;
+  if (!evaluator.EvaluateForValue(ra_rule_, &ra))
+    return false;
+
+  // Now, compute values for all the registers register_rules_ mentions.
+  for (RuleMap::const_iterator it = register_rules_.begin();
+       it != register_rules_.end(); it++) {
+    V value;
+    working = registers;
+    working[".cfa"] = cfa;
+    if (!evaluator.EvaluateForValue(it->second, &value))
+      return false;
+    (*caller_registers)[it->first] = value;
+  }
+
+  (*caller_registers)[".ra"] = ra;
+  (*caller_registers)[".cfa"] = cfa;
+
+  return true;
+}
+
+// Explicit instantiations for 32-bit and 64-bit architectures.
+template bool CFIFrameInfo::FindCallerRegs<u_int32_t>(
+    const RegisterValueMap<u_int32_t> &registers,
+    const MemoryRegion &memory,
+    RegisterValueMap<u_int32_t> *caller_registers) const;
+template bool CFIFrameInfo::FindCallerRegs<u_int64_t>(
+    const RegisterValueMap<u_int64_t> &registers,
+    const MemoryRegion &memory,
+    RegisterValueMap<u_int64_t> *caller_registers) const;
+
+bool CFIRuleParser::Parse(const string &rule_set) {
+  size_t rule_set_len = rule_set.size();
+  scoped_array<char> working_copy(new char[rule_set_len + 1]);
+  memcpy(working_copy.get(), rule_set.data(), rule_set_len);
+  working_copy[rule_set_len] = '\0';
+
+  name_.clear();
+  expression_.clear();
+
+  char *cursor;
+  static const char token_breaks[] = " \t\r\n";
+  char *token = strtok_r(working_copy.get(), token_breaks, &cursor);
+
+  for (;;) {
+    // End of rule set?
+    if (!token) return Report();
+
+    // Register/pseudoregister name?
+    size_t token_len = strlen(token);
+    if (token_len >= 1 && token[token_len - 1] == ':') {
+      // Names can't be empty.
+      if (token_len < 2) return false;
+      // If there is any pending content, report it.
+      if (!name_.empty() || !expression_.empty()) {
+        if (!Report()) return false;
+      }
+      name_.assign(token, token_len - 1);
+      expression_.clear();
+    } else {
+      // Another expression component.
+      assert(token_len > 0); // strtok_r guarantees this, I think.
+      if (!expression_.empty())
+        expression_ += ' ';
+      expression_ += token;
+    }
+    token = strtok_r(NULL, token_breaks, &cursor);
+  }
+}
+
+bool CFIRuleParser::Report() {
+  if (name_.empty() || expression_.empty()) return false;
+  if (name_ == ".cfa") handler_->CFARule(expression_);
+  else if (name_ == ".ra") handler_->RARule(expression_);
+  else handler_->RegisterRule(name_, expression_);
+  return true;
+}
+
+void CFIFrameInfoParseHandler::CFARule(const string &expression) {
+  frame_info_->SetCFARule(expression);
+}
+
+void CFIFrameInfoParseHandler::RARule(const string &expression) {
+  frame_info_->SetRARule(expression);
+}
+
+void CFIFrameInfoParseHandler::RegisterRule(const string &name,
+                                            const string &expression) {
+  frame_info_->SetRegisterRule(name, expression);
+}
+
+} // namespace google_breakpad