From 4eaf8ef5cbc1a41a4add1a72de7cc12f3df68f60 Mon Sep 17 00:00:00 2001
From: Kevin Enderby <enderby@apple.com>
Date: Thu, 1 Nov 2012 17:31:35 +0000
Subject: [PATCH] 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 | 21 +++++++++++++++++++--
 llvm/test/MC/MachO/gen-dwarf-cpp.s | 22 ++++++++++++++++++++++
 2 files changed, 41 insertions(+), 2 deletions(-)
 create mode 100644 llvm/test/MC/MachO/gen-dwarf-cpp.s

diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index e8a87b0..ae3d660 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/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());
   }
diff --git a/llvm/test/MC/MachO/gen-dwarf-cpp.s b/llvm/test/MC/MachO/gen-dwarf-cpp.s
new file mode 100644
index 0000000..cb749f4
--- /dev/null
+++ b/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
-- 
2.7.4