[yaml2obj/obj2yaml][MachO] Allow setting custom section data

Reviewers: alexshap, jhenderson, rupprecht

Reviewed By: alexshap, jhenderson

Subscribers: abrachet, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65799

llvm-svn: 369348

3 files changed, 24 insertions, 9 deletions

diff --git a/llvm/lib/Object/MachOObjectFile.cpp b/llvm/lib/Object/MachOObjectFile.cpp
index be1950e08ed..fdba3442af2 100644
--- a/llvm/lib/Object/MachOObjectFile.cpp
+++ b/llvm/lib/Object/MachOObjectFile.cpp
@@ -1945,6 +1945,11 @@ uint64_t MachOObjectFile::getSectionSize(DataRefImpl Sec) const {
   return SectSize;
 }
 
+ArrayRef<uint8_t> MachOObjectFile::getSectionContents(uint32_t Offset,
+                                                      uint64_t Size) const {
+  return arrayRefFromStringRef(getData().substr(Offset, Size));
+}
+
 Expected<ArrayRef<uint8_t>>
 MachOObjectFile::getSectionContents(DataRefImpl Sec) const {
   uint32_t Offset;
@@ -1960,7 +1965,7 @@ MachOObjectFile::getSectionContents(DataRefImpl Sec) const {
     Size = Sect.size;
   }
 
-  return arrayRefFromStringRef(getData().substr(Offset, Size));
+  return getSectionContents(Offset, Size);
 }
 
 uint64_t MachOObjectFile::getSectionAlignment(DataRefImpl Sec) const {
diff --git a/llvm/lib/ObjectYAML/MachOEmitter.cpp b/llvm/lib/ObjectYAML/MachOEmitter.cpp
index e7789d06cf7..47d7667787b 100644
--- a/llvm/lib/ObjectYAML/MachOEmitter.cpp
+++ b/llvm/lib/ObjectYAML/MachOEmitter.cpp
@@ -262,11 +262,6 @@ Error MachOWriter::writeLoadCommands(raw_ostream &OS) {
   return Error::success();
 }
 
-static bool isVirtualSection(uint8_t type) {
-  return (type == MachO::S_ZEROFILL || type == MachO::S_GB_ZEROFILL ||
-          type == MachO::S_THREAD_LOCAL_ZEROFILL);
-}
-
 Error MachOWriter::writeSectionData(raw_ostream &OS) {
   bool FoundLinkEditSeg = false;
   for (auto &LC : Obj.LoadCommands) {
@@ -311,11 +306,17 @@ Error MachOWriter::writeSectionData(raw_ostream &OS) {
         }
 
         // Skip if it's a virtual section.
-        if (isVirtualSection(Sec.flags & MachO::SECTION_TYPE))
+        if (MachO::isVirtualSection(Sec.flags & MachO::SECTION_TYPE))
           continue;
 
-        // Fill section data with 0xDEADBEEF
-        Fill(OS, Sec.size, 0xDEADBEEFu);
+        if (Sec.content) {
+          yaml::BinaryRef Content = *Sec.content;
+          Content.writeAsBinary(OS);
+          ZeroFillBytes(OS, Sec.size - Content.binary_size());
+        } else {
+          // Fill section data with 0xDEADBEEF.
+          Fill(OS, Sec.size, 0xDEADBEEFu);
+        }
       }
       uint64_t segSize = is64Bit ? LC.Data.segment_command_64_data.filesize
                                  : LC.Data.segment_command_data.filesize;
diff --git a/llvm/lib/ObjectYAML/MachOYAML.cpp b/llvm/lib/ObjectYAML/MachOYAML.cpp
index d12f12cf443..0f7cd1e1495 100644
--- a/llvm/lib/ObjectYAML/MachOYAML.cpp
+++ b/llvm/lib/ObjectYAML/MachOYAML.cpp
@@ -287,6 +287,15 @@ void MappingTraits<MachOYAML::Section>::mapping(IO &IO,
   IO.mapRequired("reserved1", Section.reserved1);
   IO.mapRequired("reserved2", Section.reserved2);
   IO.mapOptional("reserved3", Section.reserved3);
+  IO.mapOptional("content", Section.content);
+}
+
+StringRef
+MappingTraits<MachOYAML::Section>::validate(IO &IO,
+                                            MachOYAML::Section &Section) {
+  if (Section.content && Section.size < Section.content->binary_size())
+    return "Section size must be greater than or equal to the content size";
+  return {};
 }
 
 void MappingTraits<MachO::build_tool_version>::mapping(