Fix more MSVC warnings, courgette/ edition.

courgette/disassembler_elf_32.cc

Index: courgette/disassembler_elf_32.cc
diff --git a/courgette/disassembler_elf_32.cc b/courgette/disassembler_elf_32.cc
index bfd1ef4acdcbad747095928b07e7f906a2149c60..ff2b9e03b611cc42717aa96a2e7525023696a242 100644
--- a/courgette/disassembler_elf_32.cc
+++ b/courgette/disassembler_elf_32.cc
@@ -405,16 +405,12 @@ 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);

[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.

-
   // Callers don't guarantee start < end
-  if (start >= end) return true;
+  if (start_file_offset >= end_file_offset) return true;
 
-  const ptrdiff_t len = end - start;  // Works because vars are byte pointers
+  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.

 
-  if (!program->EmitBytesInstruction(start, len))
+  if (!program->EmitBytesInstruction(OffsetToPointer(start_file_offset), len))
     return false;
 
   return true;