From 9100a78bce4e1d34d8ffd5efa2cc79ed864dd1c0 Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Wed, 15 Jun 2011 06:37:58 +0000
Subject: [PATCH] Teach the .ll parser to handle named metadata with non-simple
 names. Unfortunately we can't follow what the rest of the language does
 (wrapping it in double-quotes) because that would cause an ambiguity with
 metadata strings, so instead we escape any unusual characters with \xx
 escaping.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133050 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/AsmParser/LLLexer.cpp |  6 ++++--
 lib/VMCore/AsmWriter.cpp  | 20 +++++++++++++++++++-
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index 014e81602d6..a363a653b21 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -422,13 +422,15 @@ static bool JustWhitespaceNewLine(const char *&Ptr) {
 ///    !
 lltok::Kind LLLexer::LexExclaim() {
   // Lex a metadata name as a MetadataVar.
-  if (isalpha(CurPtr[0])) {
+  if (isalpha(CurPtr[0]) || CurPtr[0] == '-' || CurPtr[0] == '$' ||
+      CurPtr[0] == '.' || CurPtr[0] == '_' || CurPtr[0] == '\\') {
     ++CurPtr;
     while (isalnum(CurPtr[0]) || CurPtr[0] == '-' || CurPtr[0] == '$' ||
-           CurPtr[0] == '.' || CurPtr[0] == '_')
+           CurPtr[0] == '.' || CurPtr[0] == '_' || CurPtr[0] == '\\')
       ++CurPtr;
 
     StrVal.assign(TokStart+1, CurPtr);   // Skip !
+    UnEscapeLexed(StrVal);
     return lltok::MetadataVar;
   }
   return lltok::exclaim;
diff --git a/lib/VMCore/AsmWriter.cpp b/lib/VMCore/AsmWriter.cpp
index 844284d09c7..cfcffebd0d2 100644
--- a/lib/VMCore/AsmWriter.cpp
+++ b/lib/VMCore/AsmWriter.cpp
@@ -1401,7 +1401,25 @@ void AssemblyWriter::printModule(const Module *M) {
 }
 
 void AssemblyWriter::printNamedMDNode(const NamedMDNode *NMD) {
-  Out << "!" << NMD->getName() << " = !{";
+  Out << '!';
+  StringRef Name = NMD->getName();
+  if (Name.empty()) {
+    Out << "<empty name> ";
+  } else {
+    if (isalpha(Name[0]) || Name[0] == '-' || Name[0] == '$' ||
+        Name[0] == '.' || Name[0] == '_')
+      Out << Name[0];
+    else
+      Out << '\\' << hexdigit(Name[0] >> 4) << hexdigit(Name[0] & 0x0F);
+    for (unsigned i = 1, e = Name.size(); i != e; ++i) {
+      unsigned char C = Name[i];
+      if (isalnum(C) || C == '-' || C == '$' || C == '.' || C == '_')
+        Out << C;
+      else
+        Out << '\\' << hexdigit(C >> 4) << hexdigit(C & 0x0F);
+    }
+  }
+  Out << " = !{";
   for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
     if (i) Out << ", ";
     int Slot = Machine.getMetadataSlot(NMD->getOperand(i));