For Darwin, emit all the text section directives together before the dwarf

section directives.  This causes the assembler to put the text sections at
the beginning of the object file, which helps work around a limitation of the
Darwin ARM relocations.  Radar 7255355.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83127 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp b/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
index df349e33b471b52d8fd001b2fd5cbaf5fff2ca28..6fc47ef7799f96401e8e014fb8d5adc1ae9b3de9 100644 (file)
--- a/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
@@ -1046,6 +1046,25 @@ void ARMAsmPrinter::printMachineInstruction(const MachineInstr *MI) {
 
 bool ARMAsmPrinter::doInitialization(Module &M) {
 
+  if (Subtarget->isTargetDarwin()) {
+    Reloc::Model RelocM = TM.getRelocationModel();
+    if (RelocM == Reloc::PIC_ || RelocM == Reloc::DynamicNoPIC) {
+      // Declare all the text sections up front (before the DWARF sections
+      // emitted by AsmPrinter::doInitialization) so the assembler will keep
+      // them together at the beginning of the object file.  This helps
+      // avoid out-of-range branches that are due a fundamental limitation of
+      // the way symbol offsets are encoded with the current Darwin ARM
+      // relocations.
+      O << "\t.section __TEXT,__text,regular\n"
+        << "\t.section __TEXT,__textcoal_nt,coalesced\n"
+        << "\t.section __TEXT,__const_coal,coalesced\n";
+      if (RelocM == Reloc::DynamicNoPIC)
+        O << "\t.section __TEXT,__symbol_stub4,symbol_stubs,none,12\n";
+      else
+        O << "\t.section __TEXT,__picsymbolstub4,symbol_stubs,none,16\n";
+    }
+  }
+
   bool Result = AsmPrinter::doInitialization(M);
   DW = getAnalysisIfAvailable<DwarfWriter>();