[llvm-objcopy][MachO] Recompute and update offset/size fields in the writer

Summary:
Recompute and update offset/size fields so that we can implement llvm-objcopy options like --only-section.

This patch is the first step and focuses on supporting load commands that covered by existing tests: executable files and
dynamic libraries are not supported.

Reviewers: alexshap, rupprecht, jhenderson

Reviewed By: alexshap, rupprecht

Subscribers: compnerd, jakehehrlich, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62652

llvm-svn: 362863

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/tools/llvm-objcopy/MachO/MachOWriter.h b/llvm/tools/llvm-objcopy/MachO/MachOWriter.h
index 9c91452a2ad..ce5bb560b9f 100644
--- a/llvm/tools/llvm-objcopy/MachO/MachOWriter.h
+++ b/llvm/tools/llvm-objcopy/MachO/MachOWriter.h
@@ -29,8 +29,14 @@ class MachOWriter {
   size_t symTableSize() const;
   size_t strTableSize() const;
 
+  void updateDySymTab(MachO::macho_load_command &MLC);
+  void updateSizeOfCmds();
+  Error layout();
+
   void writeHeader();
   void writeLoadCommands();
+  template <typename StructType>
+  void writeSectionInLoadCommand(const Section &Sec, uint8_t *&Out);
   void writeSections();
   void writeSymbolTable();
   void writeStringTable();
@@ -46,6 +52,7 @@ public:
       : O(O), Is64Bit(Is64Bit), IsLittleEndian(IsLittleEndian), B(B) {}
 
   size_t totalSize() const;
+  Error finalize();
   Error write();
 };