Fix more MSVC warnings, courgette/ edition.

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 387 matching lines @@
   }
 
   // Rest of the section (if any)
   return ParseSimpleRegion(file_offset, section_end, program);
 }
 
 CheckBool DisassemblerElf32::ParseSimpleRegion(
     size_t start_file_offset,
     size_t end_file_offset,
     AssemblyProgram* program) {
+  // Callers don't guarantee start < end
+  if (start_file_offset >= end_file_offset) return true;
 
-  const uint8* start = OffsetToPointer(start_file_offset);
-  const uint8* end = OffsetToPointer(end_file_offset);

[Peter Kasting, 2014/09/30 00:08:01]

There's no real gain to converting the offsets to pointers, since
OffsetToPointer() is always going to add the same value, so the math below works
fine without doing this.

+  const size_t len = end_file_offset - start_file_offset;

[Peter Kasting, 2014/09/30 00:08:01]

Since we know end > start, storing this as a size_t is safe, and conceptually,
it's more correct to use a size_t than a ptrdiff_t for a length of some memory
object.

 
-  // Callers don't guarantee start < end
-  if (start >= end) return true;
-
-  const ptrdiff_t len = end - start;  // Works because vars are byte pointers
-
-  if (!program->EmitBytesInstruction(start, len))
+  if (!program->EmitBytesInstruction(OffsetToPointer(start_file_offset), 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++) {
@@ skipping 69 matching lines @@
       return false;
   }
 
   std::sort(rel32_locations_.begin(),
             rel32_locations_.end(),
             TypedRVA::IsLessThan);
   return true;
 }
 
 }  // namespace courgette