From e82ada6983858183ac591f7147b685e5bf16995b Mon Sep 17 00:00:00 2001
From: Kevin Enderby <enderby@apple.com>
Date: Wed, 16 Jan 2013 17:46:23 +0000
Subject: [PATCH] We want the dwarf AT_producer for assembly source files to
 match clang's AT_producer.  Which includes clang's version information so we
 can tell which version of the compiler was used.

This is the first of two steps to allow us to do that.  This is the llvm-mc
change to provide a method to set the AT_producer string.  The second step,
coming soon to a clang near you, will have the clang driver pass the value
of getClangFullVersion() via an flag when invoking the integrated assembler
on assembly source files.

rdar://12955296

llvm-svn: 172630
---
 llvm/include/llvm/MC/MCContext.h        |  7 +++++++
 llvm/lib/MC/MCDwarf.cpp                 | 12 +++++++++---
 llvm/test/MC/MachO/gen-dwarf-producer.s |  8 ++++++++
 llvm/tools/llvm-mc/llvm-mc.cpp          | 11 +++++++++++
 4 files changed, 35 insertions(+), 3 deletions(-)
 create mode 100644 llvm/test/MC/MachO/gen-dwarf-producer.s

diff --git a/llvm/include/llvm/MC/MCContext.h b/llvm/include/llvm/MC/MCContext.h
index e92d3b9..f6ae6479 100644
--- a/llvm/include/llvm/MC/MCContext.h
+++ b/llvm/include/llvm/MC/MCContext.h
@@ -129,6 +129,10 @@ namespace llvm {
     /// non-empty.
     StringRef DwarfDebugFlags;
 
+    /// The string to embed in as the dwarf AT_producer for the compile unit, if
+    /// non-empty.
+    StringRef DwarfDebugProducer;
+
     /// Honor temporary labels, this is useful for debugging semantic
     /// differences between temporary and non-temporary labels (primarily on
     /// Darwin).
@@ -346,6 +350,9 @@ namespace llvm {
     void setDwarfDebugFlags(StringRef S) { DwarfDebugFlags = S; }
     StringRef getDwarfDebugFlags() { return DwarfDebugFlags; }
 
+    void setDwarfDebugProducer(StringRef S) { DwarfDebugProducer = S; }
+    StringRef getDwarfDebugProducer() { return DwarfDebugProducer; }
+
     /// @}
 
     char *getSecureLogFile() { return SecureLogFile; }
diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index 5691822..74851ce 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -638,9 +638,15 @@ static void EmitGenDwarfInfo(MCStreamer *MCOS,
   }
 
   // AT_producer, the version of the assembler tool.
-  MCOS->EmitBytes(StringRef("llvm-mc (based on LLVM "));
-  MCOS->EmitBytes(StringRef(PACKAGE_VERSION));
-  MCOS->EmitBytes(StringRef(")"));
+  StringRef DwarfDebugProducer = context.getDwarfDebugProducer();
+  if (!DwarfDebugProducer.empty()){
+    MCOS->EmitBytes(DwarfDebugProducer);
+  }
+  else {
+    MCOS->EmitBytes(StringRef("llvm-mc (based on LLVM "));
+    MCOS->EmitBytes(StringRef(PACKAGE_VERSION));
+    MCOS->EmitBytes(StringRef(")"));
+  }
   MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
 
   // AT_language, a 4 byte value.  We use DW_LANG_Mips_Assembler as the dwarf2
diff --git a/llvm/test/MC/MachO/gen-dwarf-producer.s b/llvm/test/MC/MachO/gen-dwarf-producer.s
new file mode 100644
index 0000000..7ccd789
--- /dev/null
+++ b/llvm/test/MC/MachO/gen-dwarf-producer.s
@@ -0,0 +1,8 @@
+// RUN: env DEBUG_PRODUCER="my producer" llvm-mc -g -triple i386-apple-darwin10 %s -filetype=obj -o %t
+// RUN: llvm-dwarfdump %t | FileCheck %s
+
+.globl _bar
+_bar:
+	ret
+
+// CHECK:    DW_AT_producer [DW_FORM_string]	("my producer")
diff --git a/llvm/tools/llvm-mc/llvm-mc.cpp b/llvm/tools/llvm-mc/llvm-mc.cpp
index e77f27e..118dd43 100644
--- a/llvm/tools/llvm-mc/llvm-mc.cpp
+++ b/llvm/tools/llvm-mc/llvm-mc.cpp
@@ -236,6 +236,13 @@ static void setDwarfDebugFlags(int argc, char **argv) {
   }
 }
 
+static std::string DwarfDebugProducer;
+static void setDwarfDebugProducer(void) {
+  if(!getenv("DEBUG_PRODUCER"))
+    return;
+  DwarfDebugProducer += getenv("DEBUG_PRODUCER");
+}
+
 static int AsLexInput(SourceMgr &SrcMgr, MCAsmInfo &MAI, tool_output_file *Out) {
 
   AsmLexer Lexer(MAI);
@@ -353,6 +360,8 @@ int main(int argc, char **argv) {
   TripleName = Triple::normalize(TripleName);
   setDwarfDebugFlags(argc, argv);
 
+  setDwarfDebugProducer();
+
   const char *ProgName = argv[0];
   const Target *TheTarget = GetTarget(ProgName);
   if (!TheTarget)
@@ -393,6 +402,8 @@ int main(int argc, char **argv) {
   Ctx.setGenDwarfForAssembly(GenDwarfForAssembly);
   if (!DwarfDebugFlags.empty())
     Ctx.setDwarfDebugFlags(StringRef(DwarfDebugFlags));
+  if (!DwarfDebugProducer.empty())
+    Ctx.setDwarfDebugProducer(StringRef(DwarfDebugProducer));
   if (!DebugCompilationDir.empty())
     Ctx.setCompilationDir(DebugCompilationDir);
   if (!MainFileName.empty())
-- 
2.7.4