[Courgette] Simplify EncodedProgram Label addition code; removed "1.01 x" memory fix.

This CL simplifies how Labels get flattened to a list of RVAs. In the past
EncodedProgram used DefineAbs32Label() / DefineRel32Label(), which let callers
add one Label at a time. Complexity arose from:
- Function pointer usage to avoid duplicate code for abs32 and rel32.
- Need for EncodedProgram to dynamically adjust size of RVA list. This led to
  inefficient array resizing, which was fixed by the "1.01 x" memory growth.

Change: We now pass the collection of abs32 and rel32 Labels to EncodedProgram.
This simplifies the interface, and allows EncodedProgram to find the max indexes
and preallocated buffers. The trade-off is increased test code complexity, since
we'd need to create Label collection.

Other changes:
- Update namespace{} for EncodedProgram and its tests.
- Add more Label constructors (for testing).
- Add LabelManager::GetIndexBound(), for LabelVector and RVAToLabel.
- Add kUnassignedRVA in image_utils.h, with checks for its absence in images.

Review URL: https://codereview.chromium.org/1571913003

Cr-Commit-Position: refs/heads/master@{#370200}

1 files changed, 3 insertions, 0 deletions

diff --git a/courgette/disassembler_win32_x64.cc b/courgette/disassembler_win32_x64.cc
index 357930d..74b0fe4 100644
--- a/courgette/disassembler_win32_x64.cc
+++ b/courgette/disassembler_win32_x64.cc
@@ -281,6 +281,7 @@ bool DisassemblerWin32X64::ParseRelocs(std::vector<RVA> *relocs) {
   }
 
   std::sort(relocs->begin(), relocs->end());
+  DCHECK(relocs->empty() || relocs->back() != kUnassignedRVA);
 
   return true;
 }
@@ -396,6 +397,8 @@ void DisassemblerWin32X64::ParseRel32RelocsFromSections() {
     file_offset += section->size_of_raw_data;
   }
   std::sort(rel32_locations_.begin(), rel32_locations_.end());
+  DCHECK(rel32_locations_.empty() ||
+         rel32_locations_.back() != kUnassignedRVA);
 
 #if COURGETTE_HISTOGRAM_TARGETS
   VLOG(1) << "abs32_locations_ " << abs32_locations_.size()