This is the second of three patches to implement support for the .loc directive

and output the dwarf line number tables.  This takes the current loc info after
an instruction is assembled and saves the needed info into an object that has
vector and for each section.  These objects will be used for the final patch to 
build and emit the encoded dwarf line number tables.  Again for now this is only
in the Mach-O streamer but at some point will move to a more generic place.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112668 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 56 insertions, 0 deletions

diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 88d9982bd2..639aa27fce 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -33,6 +33,7 @@ private:
   void EmitInstToFragment(const MCInst &Inst);
   void EmitInstToData(const MCInst &Inst);
   // FIXME: These will likely moved to a better place.
+  void MakeLineEntryForSection(const MCSection *Section);
   const MCExpr * MakeStartMinusEndExpr(MCSymbol *Start, MCSymbol *End,
                                                         int IntVal);
   void EmitDwarfFileTable(void);
@@ -409,6 +410,10 @@ void MCMachOStreamer::EmitInstruction(const MCInst &Inst) {
 
   getCurrentSectionData()->setHasInstructions(true);
 
+  // Now that a machine instruction has been assembled into this section, make
+  // a line entry for any .loc directive that has been seen.
+  MakeLineEntryForSection(getCurrentSection());
+
   // If this instruction doesn't need relaxation, just emit it as data.
   if (!getAssembler().getBackend().MayNeedRelaxation(Inst)) {
     EmitInstToData(Inst);
@@ -431,6 +436,47 @@ void MCMachOStreamer::EmitInstruction(const MCInst &Inst) {
 }
 
 //
+// This is called when an instruction is assembled into the specified section
+// and if there is information from the last .loc directive that has yet to have
+// a line entry made for it is made.
+//
+void MCMachOStreamer::MakeLineEntryForSection(const MCSection *Section) {
+  if (!getContext().getDwarfLocSeen())
+    return;
+
+  // Create a symbol at in the current section for use in the line entry.
+  MCSymbol *LineSym = getContext().CreateTempSymbol();
+  // Set the value of the symbol to use for the MCLineEntry.
+  EmitLabel(LineSym);
+
+  // Get the current .loc info saved in the context.
+  const MCDwarfLoc &DwarfLoc = getContext().getCurrentDwarfLoc();
+
+  // Create a (local) line entry with the symbol and the current .loc info.
+  MCLineEntry LineEntry(LineSym, DwarfLoc);
+
+  // clear DwarfLocSeen saying the current .loc info is now used.
+  getContext().clearDwarfLocSeen();
+
+  // Get the MCLineSection for this section, if one does not exist for this
+  // section create it.
+  DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
+    getContext().getMCLineSections();
+  MCLineSection *LineSection = MCLineSections[Section];
+  if (!LineSection) {
+    // Create a new MCLineSection.  This will be deleted after the dwarf line
+    // table is created using it by iterating through the MCLineSections
+    // DenseMap.
+    LineSection = new MCLineSection;
+    // Save a pointer to the new LineSection into the MCLineSections DenseMap.
+    MCLineSections[Section] = LineSection;
+  }
+
+  // Add the line entry to this section's entries.
+  LineSection->addLineEntry(LineEntry);
+}
+
+//
 // This helper routine returns an expression of End - Start + IntVal for use
 // by EmitDwarfFileTable() below.
 // 
@@ -552,6 +598,16 @@ void MCMachOStreamer::EmitDwarfFileTable(void) {
 
   // TODO: This is the point where the line tables would be emitted.
 
+  // Delete the MCLineSections that were created in 
+  // MCMachOStreamer::MakeLineEntryForSection() and used to emit the line
+  // tables.
+  DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
+    getContext().getMCLineSections();
+  for (DenseMap<const MCSection *, MCLineSection *>::iterator it =
+	MCLineSections.begin(), ie = MCLineSections.end(); it != ie; ++it) {
+    delete it->second;
+  }
+
   // If there are no line tables emited then we emit:
   // The following DW_LNE_set_address sequence to set the address to zero
   //   TODO test for 32-bit or 64-bit output