Breakpad Linux dumper: Make StabsReader independent of endianness and word size.

StabsReader simply applies a reinterpret_cast to treat the stab entry data
as an array of 'struct nlist' structures, making the parser specific on the
host endianness, word size, and alignment rules. On Mac OS X, a single fat
binary file may contain object files of different ABIs, of which the user
chooses one at run time.

This patch changes the parser to read the data using the google_breakpad::
ByteCursor class, which can handle different endiannesses and word sizes.
The StabsReader constructor now takes arguments indicating the endianness
of the data and the size of each entry's value field. The patch changes
src/common/linux/dump_symbols.cc to pass the new argument.

This patch changes the StabsReader unit tests to use the google_breakpad::
TestAssembler classes to generate test data, rather than reading it from a
file. This makes it easy to generate test data in various endiannesses and
word sizes. It also adds tests for the new parser behaviors.

a=jimblandy, r=thestig


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@583 4c0a9323-5329-0410-9bdc-e9ce6186880e

11 files changed, 443 insertions, 593 deletions

diff --git a/src/common/linux/dump_symbols.cc b/src/common/linux/dump_symbols.cc
index c3648e9a..da4263f7 100644
--- a/src/common/linux/dump_symbols.cc
+++ b/src/common/linux/dump_symbols.cc
@@ -123,17 +123,31 @@ static const ElfW(Shdr) *FindSectionByName(const char *name,
   return NULL;
 }
 
-static bool LoadStabs(const ElfW(Shdr) *stab_section,
+static bool LoadStabs(const ElfW(Ehdr) *elf_header,
+                      const ElfW(Shdr) *stab_section,
                       const ElfW(Shdr) *stabstr_section,
                       Module *module) {
+  // Figure out what endianness this file is.
+  bool big_endian;
+  if (elf_header->e_ident[EI_DATA] == ELFDATA2LSB)
+    big_endian = false;
+  else if (elf_header->e_ident[EI_DATA] == ELFDATA2MSB)
+    big_endian = true;
+  else {
+    fprintf(stderr, "bad data encoding in ELF header: %d\n",
+            elf_header->e_ident[EI_DATA]);
+    return false;
+  }
   // A callback object to handle data from the STABS reader.
   DumpStabsHandler handler(module);
   // Find the addresses of the STABS data, and create a STABS reader object.
+  // On Linux, STABS entries always have 32-bit values, regardless of the
+  // address size of the architecture whose code they're describing.
   uint8_t *stabs = reinterpret_cast<uint8_t *>(stab_section->sh_offset);
   uint8_t *stabstr = reinterpret_cast<uint8_t *>(stabstr_section->sh_offset);
   google_breakpad::StabsReader reader(stabs, stab_section->sh_size,
                                       stabstr, stabstr_section->sh_size,
-                                      &handler);
+                                      big_endian, 4, &handler);
   // Read the STABS data, and do post-processing.
   if (!reader.Process())
     return false;
@@ -330,7 +344,7 @@ static bool LoadSymbols(const std::string &obj_file, ElfW(Ehdr) *elf_header,
     const ElfW(Shdr) *stabstr_section = stab_section->sh_link + sections;
     if (stabstr_section) {
       found_debug_info_section = true;
-      if (!LoadStabs(stab_section, stabstr_section, module))
+      if (!LoadStabs(elf_header, stab_section, stabstr_section, module))
         fprintf(stderr, "%s: \".stab\" section found, but failed to load STABS"
                 " debugging information\n", obj_file.c_str());
     }
diff --git a/src/common/stabs_reader.cc b/src/common/stabs_reader.cc
index 7c2b1cc4..add2a8dd 100644
--- a/src/common/stabs_reader.cc
+++ b/src/common/stabs_reader.cc
@@ -31,48 +31,64 @@
 // This file implements the google_breakpad::StabsReader class.
 // See stabs_reader.h.
 
-#include <a.out.h>
-#include <stab.h>
-#include <cstring>
-#include <cassert>
-
 #include "common/stabs_reader.h"
 
+#include <assert.h>
+#include <stab.h>
+#include <string.h>
+
 namespace google_breakpad {
 
+StabsReader::EntryIterator::EntryIterator(const ByteBuffer *buffer,
+                                          bool big_endian, size_t value_size)
+    : value_size_(value_size), cursor_(buffer, big_endian) {
+  // Actually, we could handle weird sizes just fine, but they're
+  // probably mistakes --- expressed in bits, say.
+  assert(value_size == 4 || value_size == 8);
+  entry_.index = 0;
+  Fetch();
+}
+
+void StabsReader::EntryIterator::Fetch() {
+  cursor_
+      .Read(4, false, &entry_.name_offset)
+      .Read(1, false, &entry_.type)
+      .Read(1, false, &entry_.other)
+      .Read(2, false, &entry_.descriptor)
+      .Read(value_size_, false, &entry_.value);
+  entry_.at_end = !cursor_;
+}
+
 StabsReader::StabsReader(const uint8_t *stab,    size_t stab_size,
                          const uint8_t *stabstr, size_t stabstr_size,
-                         StabsHandler *handler) :
-    stabstr_(stabstr),
-    stabstr_size_(stabstr_size),
-    handler_(handler),
-    string_offset_(0),
-    next_cu_string_offset_(0),
-    symbol_(NULL),
-    current_source_file_(NULL) { 
-  symbols_ = reinterpret_cast<const struct nlist *>(stab);
-  symbols_end_ = symbols_ + (stab_size / sizeof (*symbols_));
-}
+                         bool big_endian, size_t value_size,
+                         StabsHandler *handler)
+    : entries_(stab, stab_size),
+      strings_(stabstr, stabstr_size),
+      iterator_(&entries_, big_endian, value_size),
+      handler_(handler),
+      string_offset_(0),
+      next_cu_string_offset_(0),
+      current_source_file_(NULL) { }
 
 const char *StabsReader::SymbolString() {
-  ptrdiff_t offset = string_offset_ + symbol_->n_un.n_strx;
-  if (offset < 0 || (size_t) offset >= stabstr_size_) {
+  ptrdiff_t offset = string_offset_ + iterator_->name_offset;
+  if (offset < 0 || (size_t) offset >= strings_.Size()) {
     handler_->Warning("symbol %d: name offset outside the string section\n",
-                      symbol_ - symbols_);
+                      iterator_->index);
     // Return our null string, to keep our promise about all names being
     // taken from the string section.
     offset = 0;
   }
-  return reinterpret_cast<const char *>(stabstr_ + offset);
+  return reinterpret_cast<const char *>(strings_.start + offset);
 }
 
 bool StabsReader::Process() {
-  symbol_ = symbols_;
-  while (symbol_ < symbols_end_) {
-    if (symbol_->n_type == N_SO) {
+  while (!iterator_->at_end) {
+    if (iterator_->type == N_SO) {
       if (! ProcessCompilationUnit())
         return false;
-    } else if (symbol_->n_type == N_UNDF) {
+    } else if (iterator_->type == N_UNDF) {
       // At the head of each compilation unit's entries there is an
       // N_UNDF stab giving the number of symbols in the compilation
       // unit, and the number of bytes that compilation unit's strings
@@ -85,16 +101,16 @@ bool StabsReader::Process() {
       // beginning. However, other linkers, like Gold, do not perform
       // this optimization.
       string_offset_ = next_cu_string_offset_;
-      next_cu_string_offset_ = SymbolValue();
-      symbol_++;
+      next_cu_string_offset_ = iterator_->value;
+      ++iterator_;
     } else
-      symbol_++;
+      ++iterator_;
   }
   return true;
 }
 
 bool StabsReader::ProcessCompilationUnit() {
-  assert(symbol_ < symbols_end_ && symbol_->n_type == N_SO);
+  assert(!iterator_->at_end && iterator_->type == N_SO);
 
   // There may be an N_SO entry whose name ends with a slash,
   // indicating the directory in which the compilation occurred.
@@ -104,32 +120,32 @@ bool StabsReader::ProcessCompilationUnit() {
     const char *name = SymbolString();
     if (name[0] && name[strlen(name) - 1] == '/') {
       build_directory = name;
-      symbol_++;
+      ++iterator_;
     }
   }
       
   // We expect to see an N_SO entry with a filename next, indicating
   // the start of the compilation unit.
   {
-    if (symbol_ >= symbols_end_ || symbol_->n_type != N_SO)
+    if (iterator_->at_end || iterator_->type != N_SO)
       return true;
     const char *name = SymbolString();
     if (name[0] == '\0') {
       // This seems to be a stray end-of-compilation-unit marker;
       // consume it, but don't report the end, since we didn't see a
       // beginning.
-      symbol_++;
+      ++iterator_;
       return true;
     }
     current_source_file_ = name;
   }
 
   if (! handler_->StartCompilationUnit(current_source_file_,
-                                       SymbolValue(),
+                                       iterator_->value,
                                        build_directory))
     return false;
 
-  symbol_++;
+  ++iterator_;
 
   // The STABS documentation says that some compilers may emit
   // additional N_SO entries with names immediately following the
@@ -137,24 +153,24 @@ bool StabsReader::ProcessCompilationUnit() {
   // Breakpad STABS reader doesn't ignore them, so we won't either.
 
   // Process the body of the compilation unit, up to the next N_SO.
-  while (symbol_ < symbols_end_ && symbol_->n_type != N_SO) {
-    if (symbol_->n_type == N_FUN) {
+  while (!iterator_->at_end && iterator_->type != N_SO) {
+    if (iterator_->type == N_FUN) {
       if (! ProcessFunction())
         return false;
     } else
       // Ignore anything else.
-      symbol_++;
+      ++iterator_;
   }
 
   // An N_SO with an empty name indicates the end of the compilation
   // unit.  Default to zero.
   uint64_t ending_address = 0;
-  if (symbol_ < symbols_end_) {
-    assert(symbol_->n_type == N_SO);
+  if (!iterator_->at_end) {
+    assert(iterator_->type == N_SO);
     const char *name = SymbolString();
     if (name[0] == '\0') {
-      ending_address = SymbolValue();
-      symbol_++;
+      ending_address = iterator_->value;
+      ++iterator_;
     }
   }
 
@@ -165,9 +181,9 @@ bool StabsReader::ProcessCompilationUnit() {
 }          
 
 bool StabsReader::ProcessFunction() {
-  assert(symbol_ < symbols_end_ && symbol_->n_type == N_FUN);
+  assert(!iterator_->at_end && iterator_->type == N_FUN);
 
-  uint64_t function_address = SymbolValue();
+  uint64_t function_address = iterator_->value;
   // The STABS string for an N_FUN entry is the name of the function,
   // followed by a colon, followed by type information for the
   // function.  We want to pass the name alone to StartFunction.
@@ -178,37 +194,37 @@ bool StabsReader::ProcessFunction() {
   std::string name(stab_string, name_end - stab_string);
   if (! handler_->StartFunction(name, function_address))
     return false;
-  symbol_++;
+  ++iterator_;
 
-  while (symbol_ < symbols_end_) {
-    if (symbol_->n_type == N_SO || symbol_->n_type == N_FUN)
+  while (!iterator_->at_end) {
+    if (iterator_->type == N_SO || iterator_->type == N_FUN)
       break;
-    else if (symbol_->n_type == N_SLINE) {
+    else if (iterator_->type == N_SLINE) {
       // The value of an N_SLINE entry is the offset of the line from
       // the function's start address.
-      uint64_t line_address = function_address + SymbolValue();
+      uint64_t line_address = function_address + iterator_->value;
       // The n_desc of a N_SLINE entry is the line number.  It's a
       // signed 16-bit field; line numbers from 32768 to 65535 are
       // stored as n-65536.
-      uint16_t line_number = symbol_->n_desc;
+      uint16_t line_number = iterator_->descriptor;
       if (! handler_->Line(line_address, current_source_file_, line_number))
         return false;
-      symbol_++;
-    } else if (symbol_->n_type == N_SOL) {
+      ++iterator_;
+    } else if (iterator_->type == N_SOL) {
       current_source_file_ = SymbolString();
-      symbol_++;
+      ++iterator_;
     } else
       // Ignore anything else.
-      symbol_++;
+      ++iterator_;
   }
 
   // If there is a subsequent N_SO or N_FUN entry, its address is our
   // end address.
   uint64_t ending_address = 0;
-  if (symbol_ < symbols_end_) {
-    assert(symbol_->n_type == N_SO || symbol_->n_type == N_FUN);
-    ending_address = SymbolValue();
-    // Note: we do not increment symbol_ here, since we haven't consumed it.
+  if (!iterator_->at_end) {
+    assert(iterator_->type == N_SO || iterator_->type == N_FUN);
+    ending_address = iterator_->value;
+    // Note: we do not advance iterator_ here, since we haven't consumed it.
   }
 
   if (! handler_->EndFunction(ending_address))
diff --git a/src/common/stabs_reader.h b/src/common/stabs_reader.h
index 5cfcdfb5..9f954650 100644
--- a/src/common/stabs_reader.h
+++ b/src/common/stabs_reader.h
@@ -38,36 +38,47 @@
 //
 // The comments here assume you understand the format.
 //
-// This parser assumes that the system's <a.out.h> and <stab.h>
-// headers accurately describe the layout of the STABS data; this code
-// will not parse STABS data for a system with a different address
-// size or endianness.
+// This parser can handle big-endian and little-endian data, and the symbol
+// values may be either 32 or 64 bits long. It handles both STABS in
+// sections (as used on Linux) and STABS appearing directly in an
+// a.out-like symbol table (as used in Darwin OS X Mach-O files).
 
-#ifndef COMMON_LINUX_STABS_READER_H__
-#define COMMON_LINUX_STABS_READER_H__
+#ifndef COMMON_STABS_READER_H__
+#define COMMON_STABS_READER_H__
 
+#include <stddef.h>
 #include <stdint.h>
-#include <cstddef>
+
+#ifdef HAVE_A_OUT_H
 #include <a.out.h>
+#endif
 
 #include <string>
 
+#include "common/byte_cursor.h"
+
 namespace google_breakpad {
 
 class StabsHandler;
 
 class StabsReader {
  public:
-  // Create a reader for the STABS debug information whose .stab
-  // section is the STAB_SIZE bytes at STAB, and whose .stabstr
-  // section is the STABSTR_SIZE bytes at STABSTR.  The reader will
-  // call the member functions of HANDLER to report the information it
-  // finds, when the reader's 'Process' member function is called.
+  // Create a reader for the STABS debug information whose .stab section is
+  // being traversed by ITERATOR, and whose .stabstr section is referred to
+  // by STRINGS. The reader will call the member functions of HANDLER to
+  // report the information it finds, when the reader's 'Process' member
+  // function is called.
+  //
+  // BIG_ENDIAN should be true if the entries in the .stab section are in
+  // big-endian form, or false if they are in little-endian form.
+  // VALUE_SIZE should be either 4 or 8, indicating the size of the 'value'
+  // field in each entry in bytes.
   // 
   // Note that, in ELF, the .stabstr section should be found using the
   // 'sh_link' field of the .stab section header, not by name.
   StabsReader(const uint8_t *stab,    size_t stab_size,
               const uint8_t *stabstr, size_t stabstr_size,
+              bool big_endian, size_t value_size,
               StabsHandler *handler);
 
   // Process the STABS data, calling the handler's member functions to
@@ -75,17 +86,82 @@ class StabsReader {
   // continue to process until we reach the end of the section.  If we
   // processed the entire section and all handlers returned true,
   // return true.  If any handler returned false, return false.
+  // 
+  // This is only meant to be called once per StabsReader instance;
+  // resuming a prior processing pass that stopped abruptly isn't supported.
   bool Process();
 
  private:
+
+  // An class for walking arrays of STABS entries. This isolates the main
+  // STABS reader from the exact format (size; endianness) of the entries
+  // themselves.
+  class EntryIterator {
+   public:
+    // The contents of a STABS entry, adjusted for the host's endianness,
+    // word size, 'struct nlist' layout, and so on.
+    struct Entry {
+      // True if this iterator has reached the end of the entry array. When
+      // this is set, the other members of this structure are not valid.
+      bool at_end;
+
+      // The number of this entry within the list.
+      size_t index;
+
+      // The current entry's name offset. This is the offset within the
+      // current compilation unit's strings, as establish by the N_UNDF entries.
+      size_t name_offset;
+
+      // The current entry's type, 'other' field, descriptor, and value.
+      unsigned char type;
+      unsigned char other;
+      short descriptor;
+      uint64_t value;
+    };
+
+    // Create a EntryIterator walking the entries in BUFFER. Treat the
+    // entries as big-endian if BIG_ENDIAN is true, as little-endian
+    // otherwise. Assume each entry has a 'value' field whose size is
+    // VALUE_SIZE.
+    //
+    // This would not be terribly clean to extend to other format variations,
+    // but it's enough to handle Linux and Mac, and we'd like STABS to die
+    // anyway.
+    //
+    // For the record: on Linux, STABS entry values are always 32 bits,
+    // regardless of the architecture address size (don't ask me why); on
+    // Mac, they are 32 or 64 bits long. Oddly, the section header's entry
+    // size for a Linux ELF .stab section varies according to the ELF class
+    // from 12 to 20 even as the actual entries remain unchanged.
+    EntryIterator(const ByteBuffer *buffer, bool big_endian, size_t value_size);
+
+    // Move to the next entry. This function's behavior is undefined if
+    // at_end() is true when it is called.
+    EntryIterator &operator++() { Fetch(); entry_.index++; return *this; }
+
+    // Dereferencing this iterator produces a reference to an Entry structure
+    // that holds the current entry's values. The entry is owned by this
+    // EntryIterator, and will be invalidated at the next call to operator++.
+    const Entry &operator*() const { return entry_; }
+    const Entry *operator->() const { return &entry_; }
+
+   private:
+    // Read the STABS entry at cursor_, and set entry_ appropriately.
+    void Fetch();
+
+    // The size of entries' value field, in bytes.
+    size_t value_size_;
+
+    // A byte cursor traversing buffer_.
+    ByteCursor cursor_;
+
+    // Values for the entry this iterator refers to.
+    Entry entry_;
+  };
+
   // Return the name of the current symbol.
   const char *SymbolString();
 
-  // Return the value of the current symbol.
-  const uint64_t SymbolValue() {
-    return symbol_->n_value;
-  }
-
   // Process a compilation unit starting at symbol_.  Return true
   // to continue processing, or false to abort.
   bool ProcessCompilationUnit();
@@ -94,10 +170,14 @@ class StabsReader {
   // Return true to continue processing, or false to abort.
   bool ProcessFunction();
 
-  // The debugging information we're reading.
-  const struct nlist *symbols_, *symbols_end_;
-  const uint8_t *stabstr_;
-  size_t stabstr_size_;
+  // The STABS entries we're parsing.
+  ByteBuffer entries_;
+
+  // The string section to which the entries refer.
+  ByteBuffer strings_;
+
+  // The iterator walking the STABS entries.
+  EntryIterator iterator_;
 
   StabsHandler *handler_;
 
@@ -108,9 +188,6 @@ class StabsReader {
   // as established by N_UNDF entries.
   size_t next_cu_string_offset_;
 
-  // The current symbol we're processing.
-  const struct nlist *symbol_;
-
   // The current source file name.
   const char *current_source_file_;
 };
@@ -203,4 +280,4 @@ class StabsHandler {
 
 } // namespace google_breakpad
 
-#endif  // COMMON_LINUX_STABS_READER_H__
+#endif  // COMMON_STABS_READER_H__
diff --git a/src/common/stabs_reader_unittest.cc b/src/common/stabs_reader_unittest.cc
index a22d9d0e..74897c46 100644
--- a/src/common/stabs_reader_unittest.cc
+++ b/src/common/stabs_reader_unittest.cc
@@ -31,7 +31,6 @@
 
 // stabs_reader_unittest.cc: Unit tests for google_breakpad::StabsReader.
 
-#include <a.out.h>
 #include <cassert>
 #include <cerrno>
 #include <cstdarg>
@@ -46,444 +45,171 @@
 
 #include "breakpad_googletest_includes.h"
 #include "common/stabs_reader.h"
+#include "common/test_assembler.h"
 
-using std::istream;
-using std::istringstream;
-using std::map;
-using std::ostream;
-using std::ostringstream;
-using std::string;
-
-using ::testing::_;
 using ::testing::Eq;
 using ::testing::InSequence;
 using ::testing::Return;
-using ::testing::Sequence;
 using ::testing::StrEq;
-
+using ::testing::_;
 using google_breakpad::StabsHandler;
 using google_breakpad::StabsReader;
+using google_breakpad::TestAssembler::Label;
+using google_breakpad::TestAssembler::Section;
+using google_breakpad::TestAssembler::kBigEndian;
+using google_breakpad::TestAssembler::kLittleEndian;
+using std::map;
+using std::string;
 
 namespace {
 
-// Mock stabs file parser
-//
-// In order to test StabsReader, we parse a human-readable input file
-// describing STABS entries into in-memory .stab and .stabstr
-// sections, and then pass those to StabsReader to look at. The
-// human-readable file is called a "mock stabs file".
-//
-// Except for compilation unit boundary lines (described below), each
-// line of a mock stabs file should have the following form:
-//
-//   TYPE OTHER DESC VALUE NAME
-// 
-// where all data is Latin-1 bytes and fields are separated by single
-// space characters, except for NAME, which may contain spaces and
-// continues to the end of the line.  The fields have the following
-// meanings:
-// 
-// - TYPE: the name of the stabs symbol type; like SO or FUN.  These are
-//   the names from /usr/include/bits/stab.def, without the leading N_.
-//
-// - OTHER, DESC, VALUE: numeric values for the n_other, n_desc, and
-//   n_value fields of the stab.  These can be decimal or hex,
-//   using C++ notation (10, 0x10)
-//   
-// - NAME: textual data for the entry.  STABS packs all kinds of
-//   interesting data into entries' NAME fields, so calling it a NAME
-//   is misleading, but that's how it is.  For SO, this may be a
-//   filename; for FUN, this is the function name, plus type data; and
-//   so on.
-//
-// A compilation unit boundary line has the form:
-//
-//  cu-boundary FILENAME
-
-// I don't know if the whole parser/handler pattern is really worth
-// the bureaucracy in this case.  But just writing it out as
-// old-fashioned functions wasn't astonishingly clear either, so it
-// seemed worth a try.
-
-// A handler class for mock stabs data.
-class MockStabsHandler {
+// A StringAssembler is a class for generating .stabstr sections to present
+// as input to the STABS parser.
+class StringAssembler: public Section {
  public:
-  MockStabsHandler() { }
-  virtual ~MockStabsHandler() { }
-  // The mock stabs parser calls this member function for each entry
-  // it parses, passing it the contents of the entry.  If this function
-  // returns true, the parser continues; if it returns false, the parser
-  // stops, and its Process member function returns false.
-  virtual bool Entry(enum __stab_debug_code type, char other, short desc,
-                     unsigned long value, const string &name) { return true; }
-  // Report a compilation unit boundary whose filename is FILENAME. As
-  // for the Entry function, this should return true to continue
-  // parsing, or false to stop processing.
-  virtual bool CUBoundary(const string &filename) { return true; }
-
-  // Report an error in parsing the mock stabs data.  If this returns true,
-  // the parser continues; if it returns false, the parser stops and
-  // its Process member function returns false.
-  virtual bool Error(const char *format, ...) = 0;
-};
-
-// A class for parsing mock stabs files.
-class MockStabsParser {
- public:
-  // Create a parser reading input from STREAM and passing data to HANDLER.
-  // Use FILENAME when reporting errors.
-  MockStabsParser(const string &filename, istream *stream,
-                  MockStabsHandler *handler);
-  // Parse data from the STREAM, invoking HANDLER->Entry for each
-  // entry we get.  Return true if we parsed all the data succesfully,
-  // or false if we stopped early because Entry returned false, or if
-  // there were any errors during parsing.
-  bool Process();
- private:
-  // A type for maps from stab type names ("SO", "SLINE", etc.) to
-  // n_type values.
-  typedef map<string, unsigned char> StabTypeNameTable;
-
-  // Initialize the table mapping STAB type names to n_type values.
-  void InitializeTypeNames();
-
-  // Parse LINE, one line of input from a mock stabs file, and pass
-  // its contents to handler_->Entry and return the boolean value that
-  // returns.  If we encounter an error parsing the line, report it
-  // using handler->Error.
-  bool ParseLine(const string &line);
-
-  const string &filename_;
-  istream *stream_;
-  MockStabsHandler *handler_;
-  int line_number_;
-  StabTypeNameTable type_names_;
-};
-
-MockStabsParser::MockStabsParser(const string &filename, istream *stream,
-                                 MockStabsHandler *handler):
-    filename_(filename), stream_(stream), handler_(handler),
-    line_number_(0) {
-  InitializeTypeNames();
-}
-
-bool MockStabsParser::Process() {
-  // Iterate once per line, including a line at EOF without a
-  // terminating newline.
-  for(;;) {
-    string line;
-    getline(*stream_, line, '\n');
-    if (line.empty() && stream_->eof())
-      break;
-    line_number_++;
-    if (! ParseLine(line))
-      return false;
+  StringAssembler() : in_cu_(false) { StartCU(); }
+
+  // Add the string S to this StringAssembler, and return the string's
+  // offset within this compilation unit's strings. If S has been added
+  // already, this returns the offset of its first instance.
+  size_t Add(const string &s) {
+    map<string, size_t>::iterator it = added_.find(s);
+    if (it != added_.end())
+      return it->second;
+    size_t offset = Size() - cu_start_;
+    AppendCString(s);
+    added_[s] = offset;
+    return offset;
   }
-  return true;
-}
 
-void MockStabsParser::InitializeTypeNames() {
-  // On GLIBC-based systems, <bits/stab.def> is a file containing a
-  // call to an unspecified macro __define_stab for each stab type.
-  // <stab.h> uses it to define the __stab_debug_code enum type.  We
-  // use it here to initialize our mapping from type names to enum
-  // values.
-  //
-  // This isn't portable to non-GLIBC systems.  Feel free to just
-  // hard-code the values if this becomes a problem.
-#  define __define_stab(name, code, str) type_names_[string(str)] = code;
-#  include <bits/stab.def>
-#  undef __define_stab
-}
+  // Start a fresh compilation unit string collection.
+  void StartCU() {
+    // Ignore duplicate calls to StartCU. Our test data don't always call
+    // StartCU at all, meaning that our constructor has to take care of it,
+    // meaning that tests that *do* call StartCU call it twice at the
+    // beginning.  This is not worth smoothing out.
+    if (in_cu_) return;
 
-bool MockStabsParser::ParseLine(const string &line) {
-  istringstream linestream(line);
-  // Allow "0x" prefix for hex, and so on.
-  linestream.unsetf(istringstream::basefield);
-  // Parse and validate the stabs type.
-  string typeName;
-  linestream >> typeName;
-  if (typeName == "cu-boundary") {
-    if (linestream.peek() == ' ')
-      linestream.get();
-    string filename;
-    getline(linestream, filename, '\n');
-    return handler_->CUBoundary(filename);
-  } else {
-    StabTypeNameTable::const_iterator typeIt = type_names_.find(typeName);
-    if (typeIt == type_names_.end())
-      return handler_->Error("%s:%d: unrecognized stab type: %s\n",
-                             filename_.c_str(), line_number_, typeName.c_str());
-    // These are int, not char and unsigned char, to ensure they're parsed
-    // as decimal numbers, not characters.
-    int otherInt, descInt;
-    unsigned long value;
-    linestream >> otherInt >> descInt >> value;
-    if (linestream.fail())
-      return handler_->Error("%s:%d: malformed mock stabs input line\n",
-                             filename_.c_str(), line_number_);
-    if (linestream.peek() == ' ')
-      linestream.get();
-    string name;
-    getline(linestream, name, '\n');
-    return handler_->Entry(static_cast<__stab_debug_code>(typeIt->second),
-                           otherInt, descInt, value, name);
-  }
-}
+    added_.clear();
+    cu_start_ = Size();
 
-// A class for constructing .stab sections.
-//
-// A .stab section is an array of struct nlist entries.  These
-// entries' n_un.n_strx fields are indices into an accompanying
-// .stabstr section.
-class StabSection {
- public:
-  StabSection(): used_(0), size_(1) {
-    entries_ = (struct nlist *) malloc(sizeof(*entries_) * size_);
-  }
-  ~StabSection() { free(entries_); }
-
-  // Append a new 'struct nlist' entry to the end of the section, and
-  // return a pointer to it.  This pointer is valid until the next
-  // call to Append.  The caller should initialize the returned entry
-  // as needed.
-  struct nlist *Append();
-  // Set the first entry's n_desc field to COUNT, and set its n_value field
-  // to STRING_SIZE.
-  void SetHeader(short count, unsigned long string_size);
-  // Set SECTION to the contents of a .stab section holding the
-  // accumulated list of entries added with Append.
-  void GetSection(string *section);
-  // Clear the array, and prepare this StabSection to accumulate a fresh
-  // set of entries.
-  void Clear();
+    // Each compilation unit's strings start with an empty string.
+    AppendCString("");
+    added_[""] = 0;
 
- private:
-  // The array of stabs entries,
-  struct nlist *entries_;
-  // The number of elements of entries_ that are used, and the allocated size
-  // of the array.
-  size_t used_, size_;
-};
-
-struct nlist *StabSection::Append() {
-  if (used_ == size_) {
-    size_ *= 2;
-    entries_ = (struct nlist *) realloc(entries_, sizeof(*entries_) * size_);
+    in_cu_ = true;
+  }
+  
+  // Finish off the current CU's strings.
+  size_t EndCU() { 
+    assert(in_cu_);
+    in_cu_ = false;
+    return Size() - cu_start_;
   }
-  assert(used_ < size_);
-  return &entries_[used_++];
-}
-
-void StabSection::SetHeader(short count, unsigned long string_size) {
-  assert(used_ >= 1);
-  entries_[0].n_desc = count;
-  entries_[0].n_value = string_size;
-}
-
-void StabSection::GetSection(string *section) {
-  section->assign(reinterpret_cast<char *>(entries_),
-                  sizeof(*entries_) * used_);
-}
-
-void StabSection::Clear() {
-  used_ = 0;
-  size_ = 1;
-  entries_ = (struct nlist *) realloc(entries_, sizeof(*entries_) * size_);
-}
 
-// A class for building .stabstr sections.
-// 
-// A .stabstr section is an array of characters containing a bunch of
-// null-terminated strings.  A string is identified by the index of
-// its initial character in the array.  The array always starts with a
-// null byte, so that an index of zero refers to the empty string.
-//
-// This implementation also ensures that if two strings are equal, we
-// assign them the same indices; most linkers do this, and some
-// clients may rely upon it.  (Note that this is not quite the same as
-// ensuring that a string only appears once in the section; you could
-// share space when one string is a suffix of another, but we don't.)
-class StabstrSection {
- public:
-  StabstrSection(): next_byte_(1) { string_indices_[""] = 0; }
-  // Ensure STR is present in the string section, and return its index.
-  size_t Insert(const string &str);
-  // Set SECTION to the contents of a .stabstr section in which the
-  // strings passed to Insert appear at the indices we promised.
-  void GetSection(string *section);
-  // Clear the contents of this StabstrSection, and prepare it to
-  // accumulate a new set of strings.
-  void Clear();
  private:
-  // Maps from strings to .stabstr indices and back.
-  typedef map<string, size_t> StringToIndex;
-  typedef map<size_t, const string *> IndexToString;
+  // The offset of the start of this compilation unit's strings.
+  size_t cu_start_;
 
-  // A map from strings to the indices we've assigned them.
-  StringToIndex string_indices_;
+  // True if we're in a CU.
+  bool in_cu_;
 
-  // The next unused byte in the section.  The next string we add
-  // will get this index.
-  size_t next_byte_;
+  // A map from the strings that have been added to this section to
+  // their starting indices within their compilation unit.
+  map<string, size_t> added_;
 };
 
-size_t StabstrSection::Insert(const string &str) {
-  StringToIndex::iterator it = string_indices_.find(str);
-  size_t index;
-  if (it != string_indices_.end()) {
-    index = it->second;
-  } else {
-    // This is the first time we've seen STR; add it to the table.
-    string_indices_[str] = next_byte_;
-    index = next_byte_;
-    next_byte_ += str.size() + 1;
+// A StabsAssembler is a class for generating .stab sections to present as
+// test input for the STABS parser.
+class StabsAssembler: public Section {
+ public:
+  // Create a StabsAssembler that uses StringAssembler for its strings.
+  StabsAssembler(StringAssembler *string_assembler) 
+      : Section(string_assembler->endianness()),
+        string_assembler_(string_assembler),
+        value_size_(0),
+        entry_count_(0),
+        cu_header_(NULL) { }
+  ~StabsAssembler() { assert(!cu_header_); }
+
+  // Accessor and setter for value_size_.
+  size_t value_size() const { return value_size_; }
+  StabsAssembler &set_value_size(size_t value_size) {
+    value_size_ = value_size;
+    return *this;
   }
-  return index;
-}
 
-void StabstrSection::GetSection(string *section) {
-  // First we have to invert the map.
-  IndexToString byIndex;
-  for (StringToIndex::const_iterator it = string_indices_.begin();
-       it != string_indices_.end(); it++)
-    byIndex[it->second] = &it->first;
-  // Now we build the .stabstr section.
-  section->clear();
-  for (IndexToString::const_iterator it = byIndex.begin();
-       it != byIndex.end(); it++) {
-    // Make sure we're actually assigning it the index we claim to be.
-    assert(it->first == section->size());
-    *section += *(it->second);
-    *section += '\0';
+  // Append a STAB entry to the end of this section with the given
+  // characteristics. NAME is the offset of this entry's name string within
+  // its compilation unit's portion of the .stabstr section; this can be a
+  // value generated by a StringAssembler. Return a reference to this
+  // StabsAssembler.
+  StabsAssembler &Stab(uint8_t type, uint8_t other, Label descriptor,
+                       Label value, Label name) {
+    D32(name);
+    D8(type);
+    D8(other);
+    D16(descriptor);
+    Append(endianness(), value_size_, value);
+    entry_count_++;
+    return *this;
   }
-}
 
-void StabstrSection::Clear() {
-  string_indices_.clear();
-  string_indices_[""] = 0;
-  next_byte_ = 1;
-}
+  // As above, but automatically add NAME to our StringAssembler.
+  StabsAssembler &Stab(uint8_t type, uint8_t other, Label descriptor,
+                       Label value, const string &name) {
+    return Stab(type, other, descriptor, value, string_assembler_->Add(name));
+  }
 
-// A mock stabs parser handler class that builds .stab and .stabstr
-// sections.
-class StabsSectionsBuilder: public MockStabsHandler {
- public:
-  // Construct a handler that will receive data from a MockStabsParser
-  // and construct .stab and .stabstr sections.  FILENAME should be
-  // the name of the mock stabs input file; we use it in error
-  // messages.
-  StabsSectionsBuilder(const string &filename)
-      : filename_(filename), error_count_(0), has_header_(false),
-        entry_count_(0) { }
-
-  // Overridden virtual member functions.
-  bool Entry(enum __stab_debug_code type, char other, short desc,
-             unsigned long value, const string &name);
-  bool CUBoundary(const string &filename);
-  bool Error(const char *format, ...);
-
-  // Set SECTION to the contents of a .stab or .stabstr section
-  // reflecting the entries that have been passed to us via Entry.
-  void GetStab(string *section);
-  void GetStabstr(string *section);
+  // Start a compilation unit named NAME, with an N_UNDF symbol to start
+  // it, and its own portion of the string section. Return a reference to
+  // this StabsAssembler.
+  StabsAssembler &StartCU(const string &name) {
+    assert(!cu_header_);
+    cu_header_ = new CUHeader;
+    string_assembler_->StartCU();
+    entry_count_ = 0;
+    return Stab(N_UNDF, 0,
+                cu_header_->final_entry_count,
+                cu_header_->final_string_size,
+                string_assembler_->Add(name));
+  }
 
+  // Close off the current compilation unit. Return a reference to this
+  // StabsAssembler.
+  StabsAssembler &EndCU() {
+    assert(cu_header_);
+    cu_header_->final_entry_count = entry_count_;
+    cu_header_->final_string_size = string_assembler_->EndCU();
+    delete cu_header_;
+    cu_header_ = NULL;
+    return *this;
+  }
+  
  private:
-  // Finish a compilation unit. If there are any entries accumulated in
-  // stab_ and stabstr_, add them as a new compilation unit to
-  // finished_cu_stabs_ and finished_cu_stabstr_, and then clear stab_ and
-  // stabstr_.
-  void FinishCU();
-
-  const string &filename_;        // input filename, for error messages
-  int error_count_;               // number of errors we've seen so far
-
-  // The following members accumulate the contents of a single compilation
-  // unit, possibly headed by an N_UNDF stab.
-  bool has_header_;               // true if we have an N_UNDF header
-  int entry_count_;               // the number of entries we've seen
-  StabSection stab_;              // 'struct nlist' entries
-  StabstrSection stabstr_;        // and the strings they love
-
-  // Accumulated .stab and .stabstr content for all compilation units.
-  string finished_cu_stab_, finished_cu_stabstr_;
-};
-
-bool StabsSectionsBuilder::Entry(enum __stab_debug_code type, char other,
-                                 short desc, unsigned long value,
-                                 const string &name) {
-  struct nlist *entry = stab_.Append();
-  entry->n_type = type;
-  entry->n_other = other;
-  entry->n_desc = desc;
-  entry->n_value = value;
-  entry->n_un.n_strx = stabstr_.Insert(name);
-  entry_count_++;
-  return true;
-}
-
-bool StabsSectionsBuilder::CUBoundary(const string &filename) {
-  FinishCU();
-  // Add a header for the compilation unit.
-  assert(!has_header_);
-  assert(entry_count_ == 0);
-  struct nlist *entry = stab_.Append();
-  entry->n_type = N_UNDF;
-  entry->n_other = 0;
-  entry->n_desc = 0;          // will be set to number of entries
-  entry->n_value = 0;         // will be set to size of .stabstr data
-  entry->n_un.n_strx = stabstr_.Insert(filename);
-  has_header_ = true;
-  // The N_UNDF header isn't included in the symbol count, so we
-  // shouldn't bump entry_count_ here.
-  return true;
-}
+  // Data used in a compilation unit header STAB that we won't know until
+  // we've finished the compilation unit.
+  struct CUHeader {
+    // The final number of entries this compilation unit will hold.
+    Label final_entry_count;
 
-void StabsSectionsBuilder::FinishCU() {
-  if (entry_count_ > 0) {
-    // Get the strings first, so we can record their size in the header.
-    string stabstr;
-    stabstr_.GetSection(&stabstr);
-    finished_cu_stabstr_ += stabstr;
-
-    // Initialize our header, if we have one, and extract the .stab data.
-    if (has_header_)
-      stab_.SetHeader(entry_count_, stabstr.size());
-    string stab;
-    stab_.GetSection(&stab);
-    finished_cu_stab_ += stab;
-  }
+    // The final size of this compilation unit's strings.
+    Label final_string_size;
+  };
 
-  stab_.Clear();
-  stabstr_.Clear();
-  has_header_ = false;
-  entry_count_ = 0;
-}
+  // The strings for our STABS entries.
+  StringAssembler *string_assembler_;
 
-bool StabsSectionsBuilder::Error(const char *format, ...) {
-  va_list args;
-  va_start(args, format);
-  vfprintf(stderr, format, args);
-  va_end(args);
-  error_count_++;
-  if (error_count_ >= 20) {
-    fprintf(stderr,
-            "%s: lots of errors; is this really a mock stabs file?\n",
-            filename_.c_str());
-    return false;
-  }
-  return true;
-}
+  // The size of the 'value' field of stabs entries in this section.
+  size_t value_size_;
 
-void StabsSectionsBuilder::GetStab(string *section) {
-  FinishCU();
-  *section = finished_cu_stab_;
-}
+  // The number of entries in this compilation unit so far.
+  size_t entry_count_;
 
-void StabsSectionsBuilder::GetStabstr(string *section) {
-  FinishCU();
-  *section = finished_cu_stabstr_;
-}
+  // Header labels for this compilation unit, if we've started one but not
+  // finished it.
+  CUHeader *cu_header_;
+};
 
 class MockStabsReaderHandler: public StabsHandler {
  public:
@@ -497,109 +223,138 @@ class MockStabsReaderHandler: public StabsHandler {
   MOCK_METHOD1(MockWarning, void(const char *));
 };
 
-// Create a StabsReader to parse the mock stabs data in INPUT_FILE,
-// passing the parsed information to HANDLER. If all goes well, return
-// the result of calling the reader's Process member function.
-// Otherwise, return false. INPUT_FILE should be relative to the top
-// of the source tree.
-static bool ApplyHandlerToMockStabsData(StabsHandler *handler,
-                                        const string &input_file) {
-  string full_input_file
-      = string(getenv("srcdir") ? getenv("srcdir") : ".") + "/" + input_file;
-
-  // Open the input file.
-  std::ifstream stream(full_input_file.c_str());
-  if (stream.fail()) {
-    fprintf(stderr, "error opening mock stabs input file %s: %s\n",
-            full_input_file.c_str(), strerror(errno));
-    return false;
-  }
-
-  // Parse the mock stabs data, and produce stabs sections to use as
-  // test input to the reader.
-  StabsSectionsBuilder builder(full_input_file);
-  MockStabsParser mock_parser(full_input_file, &stream, &builder);
-  if (!mock_parser.Process())
-    return false;
+// Create a StabsReader to parse the mock stabs data in STABS_ASSEMBLER and
+// STRINGS_ASSEMBLER, and pass the parsed information to HANDLER. Use the
+// endianness and value size of STABS_ASSEMBLER to parse the data. If all
+// goes well, return the result of calling the reader's Process member
+// function. Otherwise, return false.
+static bool ApplyHandlerToMockStabsData(StabsAssembler *stabs_assembler,
+                                        StringAssembler *strings_assembler,
+                                        StabsHandler *handler) {
   string stab, stabstr;
-  builder.GetStab(&stab);
-  builder.GetStabstr(&stabstr);
+  if (!stabs_assembler->GetContents(&stab) ||
+      !strings_assembler->GetContents(&stabstr))
+    return false;
 
   // Run the parser on the test input, passing whatever we find to HANDLER.
   StabsReader reader(
       reinterpret_cast<const uint8_t *>(stab.data()),    stab.size(),
       reinterpret_cast<const uint8_t *>(stabstr.data()), stabstr.size(),
+      stabs_assembler->endianness() == kBigEndian,
+      stabs_assembler->value_size(),
       handler);
   return reader.Process();
 }
 
 TEST(StabsReader, MockStabsInput) {
+  StringAssembler strings;
+  StabsAssembler stabs(&strings);
+  stabs.set_endianness(kLittleEndian);
+  stabs.set_value_size(4);
+  stabs
+      .Stab(N_SO,      149, 40232, 0x18a2a72bU, "builddir/")
+      .Stab(N_FUN,      83, 50010, 0x91a5353fU, 
+            "not the SO with source file name we expected ")
+      .Stab(N_SO,      165, 24791, 0xfe69d23cU, "")
+      .Stab(N_SO,      184, 34178, 0xca4d883aU, "builddir1/")
+      .Stab(N_SO,       83, 40859, 0xd2fe5df3U, "file1.c")
+      .Stab(N_LSYM,    147, 39565, 0x60d4bb8aU, "not the FUN we're looking for")
+      .Stab(N_FUN,     120, 50271, 0xa049f4b1U, "fun1")
+      .Stab(N_BINCL,   150, 15694, 0xef65c659U, 
+            "something to ignore in a FUN body")
+      .Stab(N_SLINE,   147,  4967, 0xd904b3f, "")
+      .Stab(N_SOL,     177, 56135, 0xbd97b1dcU, "header.h")
+      .Stab(N_SLINE,   130, 24610, 0x90f145b, "")
+      .Stab(N_FUN,      45, 32441, 0xbf27cf93U, 
+            "fun2:some stabs type info here:to trim from the name")
+      .Stab(N_SLINE,   138, 39002, 0x8148b87, "")
+      .Stab(N_SOL,      60, 49318, 0x1d06e025U, "file1.c")
+      .Stab(N_SLINE,    29, 52163, 0x6eebbb7, "")
+      .Stab(N_SO,      167,  4647, 0xd04b7448U, "")
+      .Stab(N_LSYM,     58, 37837, 0xe6b14d37U, "")
+      .Stab(N_SO,      152,  7810, 0x11759f10U, "file3.c")
+      .Stab(N_SO,      218, 12447, 0x11cfe4b5U, "");
+
   MockStabsReaderHandler mock_handler;
 
   {
     InSequence s;
 
-    EXPECT_CALL(mock_handler, StartCompilationUnit(StrEq("file1.c"), 
-                                                   0x42, StrEq("builddir1/")))
+    EXPECT_CALL(mock_handler,
+                StartCompilationUnit(StrEq("file1.c"), 0xd2fe5df3U,
+                                     StrEq("builddir1/")))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, StartFunction(StrEq("fun1"), 0x62))
+    EXPECT_CALL(mock_handler, StartFunction(StrEq("fun1"), 0xa049f4b1U))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, Line(0xe4, StrEq("file1.c"), 91))
+    EXPECT_CALL(mock_handler,
+                Line(0xa049f4b1U + 0xd904b3f, StrEq("file1.c"), 4967))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, Line(0x164, StrEq("header.h"), 111))
+    EXPECT_CALL(mock_handler,
+                Line(0xa049f4b1U + 0x90f145b, StrEq("header.h"), 24610))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, EndFunction(0x112))
+    EXPECT_CALL(mock_handler, EndFunction(0xbf27cf93U))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, StartFunction(StrEq("fun2"), 0x112))
+    EXPECT_CALL(mock_handler, StartFunction(StrEq("fun2"), 0xbf27cf93U))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, Line(0x234, StrEq("header.h"), 131))
+    EXPECT_CALL(mock_handler,
+                Line(0xbf27cf93U + 0x8148b87, StrEq("header.h"), 39002))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, Line(0x254, StrEq("file1.c"), 151))
+    EXPECT_CALL(mock_handler,
+                Line(0xbf27cf93U + 0x6eebbb7, StrEq("file1.c"), 52163))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, EndFunction(0x152))
+    EXPECT_CALL(mock_handler, EndFunction(0xd04b7448U))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, EndCompilationUnit(0x152))
+    EXPECT_CALL(mock_handler, EndCompilationUnit(0xd04b7448U))
         .WillOnce(Return(true));
     EXPECT_CALL(mock_handler, StartCompilationUnit(StrEq("file3.c"), 
-                                                   0x182, NULL))
+                                                   0x11759f10U, NULL))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, EndCompilationUnit(0x192))
+    EXPECT_CALL(mock_handler, EndCompilationUnit(0x11cfe4b5U))
         .WillOnce(Return(true));
   }
 
-  ASSERT_TRUE(ApplyHandlerToMockStabsData(
-                  &mock_handler, 
-                  "common/testdata/stabs_reader_unittest.input1"));
+  ASSERT_TRUE(ApplyHandlerToMockStabsData(&stabs, &strings, &mock_handler));
 }
 
 TEST(StabsReader, AbruptCU) {
+  StringAssembler strings;
+  StabsAssembler stabs(&strings);
+  stabs.set_endianness(kBigEndian);
+  stabs.set_value_size(4);
+  stabs.Stab(N_SO, 177, 23446, 0xbf10d5e4, "file2-1.c");
+
   MockStabsReaderHandler mock_handler;
 
   {
     InSequence s;
 
     EXPECT_CALL(mock_handler,
-                StartCompilationUnit(StrEq("file2-1.c"), 0x12, NULL))
+                StartCompilationUnit(StrEq("file2-1.c"), 0xbf10d5e4, NULL))
         .WillOnce(Return(true));
     EXPECT_CALL(mock_handler, EndCompilationUnit(NULL))
         .WillOnce(Return(true));
   }
 
-  ASSERT_TRUE(ApplyHandlerToMockStabsData(
-                  &mock_handler, 
-                  "common/testdata/stabs_reader_unittest.input2"));
+  ASSERT_TRUE(ApplyHandlerToMockStabsData(&stabs, &strings, &mock_handler));
 }
 
 TEST(StabsReader, AbruptFunction) {
   MockStabsReaderHandler mock_handler;
+  StringAssembler strings;
+  StabsAssembler stabs(&strings);
+  stabs.set_endianness(kLittleEndian);
+  stabs.set_value_size(8);
+  stabs
+      .Stab(N_SO,      218,   26631,   0xb83ddf10U, "file3-1.c")
+      .Stab(N_FUN,     113,   24765,   0xbbd4a145U, "fun3_1");
 
   {
     InSequence s;
 
     EXPECT_CALL(mock_handler,
-                StartCompilationUnit(StrEq("file3-1.c"), 0x12, NULL))
+                StartCompilationUnit(StrEq("file3-1.c"), 0xb83ddf10U, NULL))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, StartFunction(StrEq("fun3_1"), 0x22))
+    EXPECT_CALL(mock_handler, StartFunction(StrEq("fun3_1"), 0xbbd4a145U))
         .WillOnce(Return(true));
     EXPECT_CALL(mock_handler, EndFunction(NULL))
         .WillOnce(Return(true));
@@ -607,12 +362,16 @@ TEST(StabsReader, AbruptFunction) {
         .WillOnce(Return(true));
   }
 
-  ASSERT_TRUE(ApplyHandlerToMockStabsData(
-                  &mock_handler, 
-                  "common/testdata/stabs_reader_unittest.input3"));
+  ASSERT_TRUE(ApplyHandlerToMockStabsData(&stabs, &strings, &mock_handler));
 }
 
 TEST(StabsReader, NoCU) {
+  StringAssembler strings;
+  StabsAssembler stabs(&strings);
+  stabs.set_endianness(kBigEndian);
+  stabs.set_value_size(8);
+  stabs.Stab(N_SO, 161, 25673, 0x8f676e7bU, "build-directory/");
+
   MockStabsReaderHandler mock_handler;
 
   EXPECT_CALL(mock_handler, StartCompilationUnit(_, _, _))
@@ -620,64 +379,80 @@ TEST(StabsReader, NoCU) {
   EXPECT_CALL(mock_handler, StartFunction(_, _))
       .Times(0);
 
-  ASSERT_TRUE(ApplyHandlerToMockStabsData(
-                  &mock_handler, 
-                  "common/testdata/stabs_reader_unittest.input4"));
-  
+  ASSERT_TRUE(ApplyHandlerToMockStabsData(&stabs, &strings, &mock_handler));
 }
 
 TEST(StabsReader, NoCUEnd) {
+  StringAssembler strings;
+  StabsAssembler stabs(&strings);
+  stabs.set_endianness(kBigEndian);
+  stabs.set_value_size(8);
+  stabs
+      .Stab(N_SO,      116,   58280,   0x2f7493c9U, "file5-1.c")
+      .Stab(N_SO,      224,   23057,   0xf9f1d50fU, "file5-2.c");
+
   MockStabsReaderHandler mock_handler;
 
   {
     InSequence s;
 
     EXPECT_CALL(mock_handler,
-                StartCompilationUnit(StrEq("file5-1.c"), 0x12, NULL))
+                StartCompilationUnit(StrEq("file5-1.c"), 0x2f7493c9U, NULL))
         .WillOnce(Return(true));
     EXPECT_CALL(mock_handler, EndCompilationUnit(NULL))
         .WillOnce(Return(true));
     EXPECT_CALL(mock_handler,
-                StartCompilationUnit(StrEq("file5-2.c"), 0x22, NULL))
+                StartCompilationUnit(StrEq("file5-2.c"), 0xf9f1d50fU, NULL))
         .WillOnce(Return(true));
     EXPECT_CALL(mock_handler, EndCompilationUnit(NULL))
         .WillOnce(Return(true));
   }
 
-  ASSERT_TRUE(ApplyHandlerToMockStabsData(
-                  &mock_handler, 
-                  "common/testdata/stabs_reader_unittest.input5"));
-  
+  ASSERT_TRUE(ApplyHandlerToMockStabsData(&stabs, &strings, &mock_handler));
 }
 
 TEST(StabsReader, MultipleCUs) {
+  StringAssembler strings;
+  StabsAssembler stabs(&strings);
+  stabs.set_endianness(kBigEndian);
+  stabs.set_value_size(4);
+  stabs
+      .StartCU("antimony")
+      .Stab(N_SO,   49, 26043, 0x7e259f1aU, "antimony")
+      .Stab(N_FUN, 101, 63253, 0x7fbcccaeU, "arsenic")
+      .Stab(N_SO,  124, 37175, 0x80b0014cU, "")
+      .EndCU()
+      .StartCU("aluminum")
+      .Stab(N_SO,   72, 23084, 0x86756839U, "aluminum")
+      .Stab(N_FUN,  59,  3305, 0xa8e120b0U, "selenium")
+      .Stab(N_SO,  178, 56949, 0xbffff983U, "")
+      .EndCU();
+
   MockStabsReaderHandler mock_handler;
 
   {
     InSequence s;
     EXPECT_CALL(mock_handler,
-                StartCompilationUnit(StrEq("antimony"), 0x12, NULL))
+                StartCompilationUnit(StrEq("antimony"), 0x7e259f1aU, NULL))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, StartFunction(Eq("arsenic"), 0x22))
+    EXPECT_CALL(mock_handler, StartFunction(Eq("arsenic"), 0x7fbcccaeU))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, EndFunction(0x32))
+    EXPECT_CALL(mock_handler, EndFunction(0x80b0014cU))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, EndCompilationUnit(0x32))
+    EXPECT_CALL(mock_handler, EndCompilationUnit(0x80b0014cU))
         .WillOnce(Return(true));
     EXPECT_CALL(mock_handler,
-                StartCompilationUnit(StrEq("aluminum"), 0x42, NULL))
+                StartCompilationUnit(StrEq("aluminum"), 0x86756839U, NULL))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, StartFunction(Eq("selenium"), 0x52))
+    EXPECT_CALL(mock_handler, StartFunction(Eq("selenium"), 0xa8e120b0U))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, EndFunction(0x62))
+    EXPECT_CALL(mock_handler, EndFunction(0xbffff983U))
         .WillOnce(Return(true));
-    EXPECT_CALL(mock_handler, EndCompilationUnit(0x62))
+    EXPECT_CALL(mock_handler, EndCompilationUnit(0xbffff983U))
         .WillOnce(Return(true));
   }
 
-  ASSERT_TRUE(ApplyHandlerToMockStabsData(
-                  &mock_handler,
-                  "common/testdata/stabs_reader_unittest.input6"));
+  ASSERT_TRUE(ApplyHandlerToMockStabsData(&stabs, &strings, &mock_handler));
 }
 
 // name duplication
diff --git a/src/common/test_assembler.cc b/src/common/test_assembler.cc
index 3fd7cad0..54092f37 100644
--- a/src/common/test_assembler.cc
+++ b/src/common/test_assembler.cc
@@ -203,6 +203,7 @@ void Label::Binding::Get(Binding **base, u_int64_t *addend) {
 template<typename Inserter>
 static inline void InsertEndian(TestAssembler::Endianness endianness,
                                 size_t size, u_int64_t number, Inserter dest) {
+  assert(size > 0);
   if (endianness == kLittleEndian) {
     for (size_t i = 0; i < size; i++) {
       *dest++ = (char) (number & 0xff);
diff --git a/src/common/testdata/stabs_reader_unittest.input1 b/src/common/testdata/stabs_reader_unittest.input1
deleted file mode 100644
index 44b3d0a3..00000000
--- a/src/common/testdata/stabs_reader_unittest.input1
+++ /dev/null
@@ -1,19 +0,0 @@
-SO      10   11   0x02 builddir/
-FUN     20   21   0x12 not the SO with source file name we expected 
-SO      30   31   0x22 
-SO      40   41   0x32 builddir1/
-SO      50   51   0x42 file1.c
-LSYM    60   61   0x52 not the FUN we're looking for
-FUN     70   71   0x62 fun1
-BINCL   80   81   0x72 something to ignore in a FUN body
-SLINE   90   91   0x82
-SOL    100  101   0x92 header.h
-SLINE  110  111  0x102
-FUN    120  121  0x112 fun2:some stabs type info here, to trim from the name
-SLINE  130  131  0x122
-SOL    140  141  0x132 file1.c
-SLINE  150  151  0x142
-SO     160  161  0x152
-LSYM   170  171  0x162
-SO     180  181  0x182 file3.c
-SO     190  191  0x192
diff --git a/src/common/testdata/stabs_reader_unittest.input2 b/src/common/testdata/stabs_reader_unittest.input2
deleted file mode 100644
index 82efeb92..00000000
--- a/src/common/testdata/stabs_reader_unittest.input2
+++ /dev/null
@@ -1 +0,0 @@
-SO      10   11   0x12 file2-1.c
diff --git a/src/common/testdata/stabs_reader_unittest.input3 b/src/common/testdata/stabs_reader_unittest.input3
deleted file mode 100644
index 73e6a302..00000000
--- a/src/common/testdata/stabs_reader_unittest.input3
+++ /dev/null
@@ -1,2 +0,0 @@
-SO      10   11   0x12 file3-1.c
-FUN     20   21   0x22 fun3_1
diff --git a/src/common/testdata/stabs_reader_unittest.input4 b/src/common/testdata/stabs_reader_unittest.input4
deleted file mode 100644
index dfdbf677..00000000
--- a/src/common/testdata/stabs_reader_unittest.input4
+++ /dev/null
@@ -1 +0,0 @@
-SO      10   11   0x12 build-directory/
diff --git a/src/common/testdata/stabs_reader_unittest.input5 b/src/common/testdata/stabs_reader_unittest.input5
deleted file mode 100644
index 7a447c88..00000000
--- a/src/common/testdata/stabs_reader_unittest.input5
+++ /dev/null
@@ -1,2 +0,0 @@
-SO      10   11   0x12 file5-1.c
-SO      20   21   0x22 file5-2.c
diff --git a/src/common/testdata/stabs_reader_unittest.input6 b/src/common/testdata/stabs_reader_unittest.input6
deleted file mode 100644
index 54c2c9d4..00000000
--- a/src/common/testdata/stabs_reader_unittest.input6
+++ /dev/null
@@ -1,8 +0,0 @@
-cu-boundary antimony
-SO      10   11   0x12 antimony
-FUN     20   21   0x22 arsenic
-SO      30   31   0x32
-cu-boundary aluminum
-SO      40   41   0x42 aluminum
-FUN     50   51   0x52 selenium
-SO      60   61   0x62