Collapsed Courgette instructions that copy file data to the patch.

courgette/disassembler_elf_32.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "courgette/disassembler_elf_32.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 390 matching lines @@
   return ParseSimpleRegion(file_offset, section_end, program);
 }
 
 CheckBool DisassemblerElf32::ParseSimpleRegion(
     size_t start_file_offset,
     size_t end_file_offset,
     AssemblyProgram* program) {
 
   const uint8* start = OffsetToPointer(start_file_offset);
   const uint8* end = OffsetToPointer(end_file_offset);
+  const uint32 len = end - start; // Works because vars are byte pointers

[Ben Chan, 2013/08/09 20:58:39]

nit: two spaces between comment

(note: generally, it's safer to use ptrdiff_t instead of uint32)

[paulgazz, 2013/08/09 23:23:31]

Done spaces.

Regarding ptrdiff_t: the underlying object takes a uint32, because it may be
passed non-pointer diff lengths also.  Will there be any problem with implicit
casting here if I just change the type of len to ptrdiff_t?

 
-  const uint8* p = start;
+  // Callers don't guarantee start < end
+  if (start >= end) return true;
 
-  while (p < end) {
-    if (!program->EmitByteInstruction(*p))
-      return false;
-    ++p;
-  }
+  if (!program->EmitBytesInstruction(start, len))
+    return false;
 
   return true;
 }
 
 CheckBool DisassemblerElf32::ParseAbs32Relocs() {
   abs32_locations_.clear();
 
   // Loop through sections for relocation sections
   for (int section_id = 0; section_id < SectionHeaderCount(); section_id++) {
     const Elf32_Shdr *section_header = SectionHeader(section_id);
@@ skipping 68 matching lines @@
       return false;
   }
 
   std::sort(rel32_locations_.begin(),
             rel32_locations_.end(),
             TypedRVA::IsLessThan);
   return true;
 }
 
 }  // namespace courgette