[llvm-commits] [PATCH 3/5] Layout helper function.

[Matt Fleming]

Introduce a helper method to add a section to the end of a layout. This
will be used by the ELF ObjectWriter code to add the metadata sections
(symbol table, etc) to the end of an object file.
---
 include/llvm/MC/MCAssembler.h |    2 ++
 lib/MC/MCAssembler.cpp        |   34 ++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/include/llvm/MC/MCAssembler.h b/include/llvm/MC/MCAssembler.h
index 24bd7d2..bade9d3 100644
--- a/include/llvm/MC/MCAssembler.h
+++ b/include/llvm/MC/MCAssembler.h
@@ -664,6 +664,8 @@ public:
   void WriteSectionData(const MCSectionData *Section, const MCAsmLayout &Layout,
                         MCObjectWriter *OW) const;
 
+  void AddSectionToTheEnd(MCSectionData &SD, MCAsmLayout &Layout);
+
 public:
   /// Construct a new assembler instance.
   ///
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index 8e255aa..35f3956 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -652,6 +652,40 @@ void MCAssembler::WriteSectionData(const MCSectionData *SD,
   assert(OW->getStream().tell() - Start == Layout.getSectionFileSize(SD));
 }
 
+void MCAssembler::AddSectionToTheEnd(MCSectionData &SD, MCAsmLayout &Layout) {
+  // Create dummy fragments and assign section ordinals.
+  unsigned SectionIndex = 0;
+  for (MCAssembler::iterator it = begin(), ie = end(); it != ie; ++it)
+    SectionIndex++;
+
+  SD.setOrdinal(SectionIndex);
+
+  // Assign layout order indices to sections and fragments.
+  unsigned FragmentIndex = 0;
+  unsigned i = 0;
+  for (unsigned e = Layout.getSectionOrder().size(); i != e; ++i) {
+    MCSectionData *SD = Layout.getSectionOrder()[i];
+
+    for (MCSectionData::iterator it2 = SD->begin(),
+           ie2 = SD->end(); it2 != ie2; ++it2)
+      FragmentIndex++;
+  }
+
+  SD.setLayoutOrder(i);
+  for (MCSectionData::iterator it2 = SD.begin(),
+         ie2 = SD.end(); it2 != ie2; ++it2) {
+    it2->setLayoutOrder(FragmentIndex++);
+  }
+  Layout.getSectionOrder().push_back(&SD);
+
+  Layout.LayoutSection(&SD);
+
+  // Layout until everything fits.
+  while (LayoutOnce(Layout))
+    continue;
+
+}
+
 void MCAssembler::Finish(MCObjectWriter *Writer) {
   DEBUG_WITH_TYPE("mc-dump", {
       llvm::errs() << "assembler backend - pre-layout\n--\n";
-- 
1.6.4.rc0