[PATCH] add targethandler callbacks from DefaultLayout/Writer

[Shankar Kalpathi Easwaran]

================
Comment at: DefaultLayout.h:396
@@ -392,2 +395,3 @@
 ErrorOr<const AtomLayout &> DefaultLayout<ELFT>::addAtom(const Atom *atom) {
+  bool isTargetSection = false;
   if (const DefinedAtom *definedAtom = dyn_cast<DefinedAtom>(atom)) {
----------------
Michael Spencer wrote:
> The scope of this var is too large.
Removed all occurences of isTargetSection

================
Comment at: DefaultLayout.h:412-415
@@ +411,6 @@
+
+    sectionName = isTargetSection ?
+                  _targetHandler.targetLayout().getSectionName(
+                      sectionName, contentType, permissions) :
+        getSectionName(sectionName, contentType, permissions);
+
----------------
Michael Spencer wrote:
> Just make getSectionName virtual. TargetLayouts are derived from DefaultTargetLayout. The derived class can just forward to the base class for things it doesn't want to handle.
Done.

================
Comment at: DefaultLayout.h:421-424
@@ -408,3 +420,6 @@
     if (_sectionMap.find(sectionKey) == _sectionMap.end()) {
       SectionOrder section_order =
+          isTargetSection ? _targetHandler.targetLayout().getSectionOrder(
+              sectionName, contentType, permissions) :
           getSectionOrder(sectionName, contentType, permissions);
+
----------------
Michael Spencer wrote:
> Same.
Done.

================
Comment at: DefaultLayout.h:426-430
@@ +425,7 @@
+
+      section =
+          isTargetSection ?
+          _targetHandler.targetLayout().getSection(sectionName, permissions) :
+          new (_allocator) Section<ELFT>(_targetInfo, sectionName, contentType,
+                                         permissions, section_order);
+
----------------
Michael Spencer wrote:
> Same.
Done.

================
Comment at: DefaultLayout.h:487
@@ -463,3 +486,3 @@
   std::stable_sort(_sections.begin(), _sections.end(),
-  [](Chunk<ELFT> *A, Chunk<ELFT> *B) {
+                   [](Chunk<ELFT> * A, Chunk<ELFT> * B) {
      return A->order() < B->order();
----------------
Michael Spencer wrote:
> clang-format messes up here sometimes. No space after *.
Done.

================
Comment at: SectionChunks.h:64
@@ +63,3 @@
+  virtual bool hasOutputSegment() {
+    assert(_sectionKind != K_Target);
+    return false;
----------------
Michael Spencer wrote:
> Needs a message.
Done.

================
Comment at: TargetLayout.h:47
@@ -59,1 +46,3 @@
+  virtual Section<ELFT> *getSection(
+      const StringRef name, DefinedAtom::ContentPermissions permissions) = 0;
 
----------------
Michael Spencer wrote:
> Don't const qualify StringRef.
Removed all occurences of const StringRef

================
Comment at: Writer.cpp:267-288
@@ -262,19 +266,24 @@
 
-  _Header->e_ident(ELF::EI_CLASS, _targetInfo.is64Bits() ? ELF::ELFCLASS64
-                                                            : ELF::ELFCLASS32);
-  _Header->e_ident(ELF::EI_DATA, _targetInfo.isLittleEndian()
-                                    ? ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
-  _Header->e_ident(ELF::EI_VERSION, 1);
-  _Header->e_ident(ELF::EI_OSABI, 0);
-  _Header->e_type(_targetInfo.getOutputType());
-  _Header->e_machine(_targetInfo.getOutputMachine());
-  _Header->e_version(1);
-  _Header->e_entry(0ULL);
-  _Header->e_phoff(_programHeader->fileOffset());
-  _Header->e_shoff(_shdrtab->fileOffset());
-  _Header->e_phentsize(_programHeader->entsize());
-  _Header->e_phnum(_programHeader->numHeaders());
-  _Header->e_shentsize(_shdrtab->entsize());
-  _Header->e_shnum(_shdrtab->numHeaders());
-  _Header->e_shstrndx(_shstrtab->ordinal());
+  if (!_targetHandler.doesOverrideHeader()) {
+    _Header->e_ident(ELF::EI_CLASS, _targetInfo.is64Bits() ? ELF::ELFCLASS64 :
+                         ELF::ELFCLASS32);
+    _Header->e_ident(ELF::EI_DATA, _targetInfo.isLittleEndian() ?
+                         ELF::ELFDATA2LSB : ELF::ELFDATA2MSB);
+    _Header->e_ident(ELF::EI_VERSION, 1);
+    _Header->e_ident(ELF::EI_OSABI, 0);
+    _Header->e_type(_targetInfo.getOutputType());
+    _Header->e_machine(_targetInfo.getOutputMachine());
+    _Header->e_version(1);
+    _Header->e_entry(0ULL);
+    _Header->e_phoff(_programHeader->fileOffset());
+    _Header->e_shoff(_shdrtab->fileOffset());
+    _Header->e_phentsize(_programHeader->entsize());
+    _Header->e_phnum(_programHeader->numHeaders());
+    _Header->e_shentsize(_shdrtab->entsize());
+    _Header->e_shnum(_shdrtab->numHeaders());
+    _Header->e_shstrndx(_shstrtab->ordinal());
+  } else {
+    // override the contents of the ELF Header
+    _targetHandler.setHeaderInfo(_Header);
+  }
   uint64_t virtualAddr = 0;
----------------
Michael Spencer wrote:
> Same thing about virtual functions here.
This cant be virtual, because its part of the writer.


http://llvm-reviews.chandlerc.com/D350