Emit DWARF info for all code section in an assembly file

Currently, when using llvm as an assembler, DWARF debug information is only
generated for the .text section. This patch modifies this so that DWARF info
is emitted for all executable sections.

llvm-svn: 211273

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index cc98be6ea63..bd2c4e960ac 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -340,6 +340,29 @@ bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
   return !MCDwarfFiles[FileNumber].Name.empty();
 }
 
+/// finalizeDwarfSections - Emit end symbols for each non-empty code section.
+/// Also remove empty sections from SectionStartEndSyms, to avoid generating
+/// useless debug info for them.
+void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
+  MCContext &context = MCOS.getContext();
+
+  auto sec = SectionStartEndSyms.begin();
+  while (sec != SectionStartEndSyms.end()) {
+    assert(sec->second.first && "Start symbol must be set by now");
+    MCOS.SwitchSection(sec->first);
+    if (MCOS.mayHaveInstructions()) {
+      MCSymbol *SectionEndSym = context.CreateTempSymbol();
+      MCOS.EmitLabel(SectionEndSym);
+      sec->second.second = SectionEndSym;
+      ++sec;
+    } else {
+      MapVector<const MCSection *, std::pair<MCSymbol *, MCSymbol *> >::iterator
+        to_erase = sec;
+      sec = SectionStartEndSyms.erase(to_erase);
+    }
+  }
+}
+
 void MCContext::FatalError(SMLoc Loc, const Twine &Msg) const {
   // If we have a source manager and a location, use it. Otherwise just
   // use the generic report_fatal_error().