Adding a collector name attribute to Function in the IR. These 
methods are new to Function:

  bool hasCollector() const;
  const std::string &getCollector() const;
  void setCollector(const std::string &);
  void clearCollector();

The assembly representation is as such:

  define void @f() gc "shadow-stack" { ...

The implementation uses an on-the-side table to map Functions to 
collector names, such that there is no overhead. A StringPool is 
further used to unique collector names, which are extremely
likely to be unique per process.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44769 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index 72e19f1d..ef8d27c 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -468,6 +468,7 @@
   KEYWORD("module", MODULE);
   KEYWORD("asm", ASM_TOK);
   KEYWORD("sideeffect", SIDEEFFECT);
+  KEYWORD("gc", GC);
   
   KEYWORD("cc", CC_TOK);
   KEYWORD("ccc", CCC_TOK);