Add support for generating dwarf debugging info with assembly files

run through the 'C' preprocessor.  That is pick up the file name
and line numbers from the cpp hash file line comments for the
dwarf file and line numbers tables.

rdar://9275556

llvm-svn: 167237

llvm/lib/MC/MCParser/AsmParser.cpp

@@ -1389,9 +1389,26 @@ bool AsmParser::ParseStatement(ParseStatementInfo &Info) {
   // the instruction.
   if (!HadError && getContext().getGenDwarfForAssembly() &&
       getContext().getGenDwarfSection() == getStreamer().getCurrentSection() ) {
+
+     unsigned Line = SrcMgr.FindLineNumber(IDLoc, CurBuffer);
+
+     // If we previously parsed a cpp hash file line comment then make sure the
+     // current Dwarf File is for the CppHashFilename if not then emit the
+     // Dwarf File table for it and adjust the line number for the .loc.
+     const std::vector<MCDwarfFile *> &MCDwarfFiles =
+       getContext().getMCDwarfFiles();
+     if (CppHashFilename.size() != 0) {
+       if(MCDwarfFiles[getContext().getGenDwarfFileNumber()]->getName() !=
+          CppHashFilename)
+	 getStreamer().EmitDwarfFileDirective(
+	   getContext().nextGenDwarfFileNumber(), StringRef(), CppHashFilename);
+
+       unsigned CppHashLocLineNo = SrcMgr.FindLineNumber(CppHashLoc, CurBuffer);
+       Line = CppHashLineNumber - 1 + (Line - CppHashLocLineNo);
+     }
+
     getStreamer().EmitDwarfLocDirective(getContext().getGenDwarfFileNumber(),
-                                        SrcMgr.FindLineNumber(IDLoc, CurBuffer),
-                                        0, DWARF2_LINE_DEFAULT_IS_STMT ?
+                                        Line, 0, DWARF2_LINE_DEFAULT_IS_STMT ?
                                         DWARF2_FLAG_IS_STMT : 0, 0, 0,
                                         StringRef());
   }

llvm/test/MC/MachO/gen-dwarf-cpp.s

@@ -0,0 +1,22 @@
+// RUN: llvm-mc -g -triple i386-apple-darwin10 %s -filetype=obj -o %t
+// RUN: llvm-dwarfdump %t | FileCheck %s
+
+# 100 "t.s" 1
+.globl _bar
+_bar:
+	movl	$0, %eax
+L1:	leave
+	ret
+
+// rdar://9275556
+
+// We check that the source name "t.s" is picked up
+// CHECK:                 Dir  Mod Time   File Len   File Name
+// CHECK:                 ---- ---------- ---------- ---------------------------
+// CHECK: file_names[  1]    1 0x00000000 0x00000000 gen-dwarf-cpp.s
+// CHECK: file_names[  2]    0 0x00000000 0x00000000 t.s
+
+// We check that the source line number 100 is picked up before the "movl"
+// CHECK: Address            Line   Column File   ISA Flags
+// CHECK: ------------------ ------ ------ ------ --- -------------
+// CHECK: 0x0000000000000000    102      0      2   0  is_stmt