Breakpad DWARF Reader: Change LineInfoHandler::AddLine to provide the line's length.

Breakpad's DWARF line number info parser provides a code address,
file, and line number for each code/source pairing, but doesn't
provide the length of the machine code. This makes that change, as
discussed in the following thread:

http://groups.google.com/group/google-breakpad-dev/browse_thread/thread/ed8d2fde79319368p

This patch also makes the corresponding changes to the functioninfo.cc
module, used by the Mac dumper. This patch has no effect on the Mac
dumper's output.

a=jimblandy, r=ccoutant


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@494 4c0a9323-5329-0410-9bdc-e9ce6186880e

4 files changed, 50 insertions, 28 deletions

diff --git a/src/common/dwarf/dwarf2reader.cc b/src/common/dwarf/dwarf2reader.cc
index 357029c2..6e3561ad 100644
--- a/src/common/dwarf/dwarf2reader.cc
+++ b/src/common/dwarf/dwarf2reader.cc
@@ -1,4 +1,4 @@
-// Copyright 2006 Google Inc. All Rights Reserved.
+// Copyright 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
@@ -844,18 +844,39 @@ void LineInfo::ReadLines() {
     lengthstart += 4;
 
   const char* lineptr = after_header_;
+  lsm.Reset(header_.default_is_stmt);
+
+  // The LineInfoHandler interface expects each line's length along
+  // with its address, but DWARF only provides addresses (sans
+  // length), and an end-of-sequence address; one infers the length
+  // from the next address. So we report a line only when we get the
+  // next line's address, or the end-of-sequence address.
+  bool have_pending_line = false;
+  uint64 pending_address = 0;
+  uint32 pending_file_num = 0, pending_line_num = 0, pending_column_num = 0;
+
   while (lineptr < lengthstart + header_.total_length) {
-    lsm.Reset(header_.default_is_stmt);
-    while (!lsm.end_sequence) {
-      size_t oplength;
-      bool add_line = ProcessOneOpcode(reader_, handler_, header_,
-                                       lineptr, &lsm, &oplength, (uintptr)-1,
-                                       NULL);
-      if (add_line)
-        handler_->AddLine(lsm.address, lsm.file_num, lsm.line_num,
-                          lsm.column_num);
-      lineptr += oplength;
+    size_t oplength;
+    bool add_row = ProcessOneOpcode(reader_, handler_, header_,
+                                    lineptr, &lsm, &oplength, (uintptr)-1,
+                                    NULL);
+    if (add_row) {
+      if (have_pending_line)
+        handler_->AddLine(pending_address, lsm.address - pending_address,
+                          pending_file_num, pending_line_num,
+                          pending_column_num);
+      if (lsm.end_sequence) {
+        lsm.Reset(header_.default_is_stmt);      
+        have_pending_line = false;
+      } else {
+        pending_address = lsm.address;
+        pending_file_num = lsm.file_num;
+        pending_line_num = lsm.line_num;
+        pending_column_num = lsm.column_num;
+        have_pending_line = true;
+      }
     }
+    lineptr += oplength;
   }
 
   after_header_ = lengthstart + header_.total_length;
diff --git a/src/common/dwarf/dwarf2reader.h b/src/common/dwarf/dwarf2reader.h
index 57667563..9f89ca8e 100644
--- a/src/common/dwarf/dwarf2reader.h
+++ b/src/common/dwarf/dwarf2reader.h
@@ -1,4 +1,4 @@
-// Copyright 2006 Google Inc. All Rights Reserved.
+// Copyright 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
@@ -167,12 +167,13 @@ class LineInfoHandler {
                           uint64 length) { }
 
   // Called when the line info reader has a new line, address pair
-  // ready for us.  ADDRESS is the address of the code, FILE_NUM is
-  // the file number containing the code, LINE_NUM is the line number in
-  // that file for the code, and COLUMN_NUM is the column number the code
-  // starts at, if we know it (0 otherwise).
-  virtual void AddLine(uint64 address, uint32 file_num, uint32 line_num,
-                       uint32 column_num) { }
+  // ready for us. ADDRESS is the address of the code, LENGTH is the
+  // length of its machine code in bytes, FILE_NUM is the file number
+  // containing the code, LINE_NUM is the line number in that file for
+  // the code, and COLUMN_NUM is the column number the code starts at,
+  // if we know it (0 otherwise).
+  virtual void AddLine(uint64 address, uint64 length,
+                       uint32 file_num, uint32 line_num, uint32 column_num) { }
 };
 
 // The base of DWARF2/3 debug info is a DIE (Debugging Information
diff --git a/src/common/dwarf/functioninfo.cc b/src/common/dwarf/functioninfo.cc
index 09aa01fd..f4582a49 100644
--- a/src/common/dwarf/functioninfo.cc
+++ b/src/common/dwarf/functioninfo.cc
@@ -1,4 +1,4 @@
-// Copyright 2006 Google Inc. All Rights Reserved.
+// Copyright 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
@@ -89,7 +89,7 @@ void CULineInfoHandler::DefineFile(const string& name,
   }
 }
 
-void CULineInfoHandler::AddLine(uint64 address, uint32 file_num,
+void CULineInfoHandler::AddLine(uint64 address, uint64 length, uint32 file_num,
                                 uint32 line_num, uint32 column_num) {
   if (file_num < files_->size()) {
     linemap_->insert(make_pair(address, make_pair(files_->at(file_num).name.c_str(),
diff --git a/src/common/dwarf/functioninfo.h b/src/common/dwarf/functioninfo.h
index 3351c67c..d941ec0d 100644
--- a/src/common/dwarf/functioninfo.h
+++ b/src/common/dwarf/functioninfo.h
@@ -1,4 +1,4 @@
-// Copyright 2006 Google Inc. All Rights Reserved.
+// Copyright 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
@@ -92,13 +92,13 @@ class CULineInfoHandler: public LineInfoHandler {
 
 
   // Called when the line info reader has a new line, address pair
-  // ready for us.  ADDRESS is the address of the code, FILE_NUM is
-  // the file number containing the code, LINE_NUM is the line number
-  // in that file for the code, and COLUMN_NUM is the column number
-  // the code starts at, if we know it (0 otherwise).
-  virtual void AddLine(uint64 address, uint32 file_num, uint32 line_num,
-                       uint32 column_num);
-
+  // ready for us. ADDRESS is the address of the code, LENGTH is the
+  // length of its machine code in bytes, FILE_NUM is the file number
+  // containing the code, LINE_NUM is the line number in that file for
+  // the code, and COLUMN_NUM is the column number the code starts at,
+  // if we know it (0 otherwise).
+  virtual void AddLine(uint64 address, uint64 length,
+                       uint32 file_num, uint32 line_num, uint32 column_num);
 
  private:
   LineMap* linemap_;