From 5e4558e5a8974efb51f6e53d8fff6f64cf3264f2 Mon Sep 17 00:00:00 2001
From: Alexey Samsonov <vonosmas@gmail.com>
Date: Wed, 10 Sep 2014 18:00:17 +0000
Subject: [PATCH] Make CallingConv::ID an alias of "unsigned".

Summary:
Make CallingConv::ID a plain unsigned instead of enum with a
fixed set of valus. LLVM IR allows arbitraty calling conventions (you are
free to write cc12345), and loading them as enum is an undefined
behavior. This was reported by UBSan.

Test Plan: llvm regression test suite

Reviewers: nicholas

Reviewed By: nicholas

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5248

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217529 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/IR/CallingConv.h |  5 ++++-
 lib/AsmParser/LLParser.cpp    | 14 +++++---------
 lib/AsmParser/LLParser.h      |  2 +-
 3 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/include/llvm/IR/CallingConv.h b/include/llvm/IR/CallingConv.h
index 1eaf4f7f469..702c35f58fa 100644
--- a/include/llvm/IR/CallingConv.h
+++ b/include/llvm/IR/CallingConv.h
@@ -20,10 +20,13 @@ namespace llvm {
 /// the well-known calling conventions.
 ///
 namespace CallingConv {
+  /// LLVM IR allows to use arbitrary numbers as calling convention identifiers.
+  typedef unsigned ID;
+
   /// A set of enums which specify the assigned numeric values for known llvm
   /// calling conventions.
   /// @brief LLVM Calling Convention Representation
-  enum ID {
+  enum {
     /// C - The default llvm calling convention, compatible with C.  This
     /// convention is the only calling convention that supports varargs calls.
     /// As with typical C calling conventions, the callee/caller have to
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index f363b550647..cfdb1d4742f 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -1464,7 +1464,7 @@ bool LLParser::ParseOptionalDLLStorageClass(unsigned &Res) {
 ///   ::= 'preserve_allcc'
 ///   ::= 'cc' UINT
 ///
-bool LLParser::ParseOptionalCallingConv(CallingConv::ID &CC) {
+bool LLParser::ParseOptionalCallingConv(unsigned &CC) {
   switch (Lex.getKind()) {
   default:                       CC = CallingConv::C; return false;
   case lltok::kw_ccc:            CC = CallingConv::C; break;
@@ -1489,12 +1489,8 @@ bool LLParser::ParseOptionalCallingConv(CallingConv::ID &CC) {
   case lltok::kw_preserve_mostcc:CC = CallingConv::PreserveMost; break;
   case lltok::kw_preserve_allcc: CC = CallingConv::PreserveAll; break;
   case lltok::kw_cc: {
-      unsigned ArbitraryCC;
       Lex.Lex();
-      if (ParseUInt32(ArbitraryCC))
-        return true;
-      CC = static_cast<CallingConv::ID>(ArbitraryCC);
-      return false;
+      return ParseUInt32(CC);
     }
   }
 
@@ -3131,7 +3127,7 @@ bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
   unsigned Visibility;
   unsigned DLLStorageClass;
   AttrBuilder RetAttrs;
-  CallingConv::ID CC;
+  unsigned CC;
   Type *RetType = nullptr;
   LocTy RetTypeLoc = Lex.getLoc();
   if (ParseOptionalLinkage(Linkage) ||
@@ -3803,7 +3799,7 @@ bool LLParser::ParseInvoke(Instruction *&Inst, PerFunctionState &PFS) {
   AttrBuilder RetAttrs, FnAttrs;
   std::vector<unsigned> FwdRefAttrGrps;
   LocTy NoBuiltinLoc;
-  CallingConv::ID CC;
+  unsigned CC;
   Type *RetType = nullptr;
   LocTy RetTypeLoc;
   ValID CalleeID;
@@ -4217,7 +4213,7 @@ bool LLParser::ParseCall(Instruction *&Inst, PerFunctionState &PFS,
   AttrBuilder RetAttrs, FnAttrs;
   std::vector<unsigned> FwdRefAttrGrps;
   LocTy BuiltinLoc;
-  CallingConv::ID CC;
+  unsigned CC;
   Type *RetType = nullptr;
   LocTy RetTypeLoc;
   ValID CalleeID;
diff --git a/lib/AsmParser/LLParser.h b/lib/AsmParser/LLParser.h
index b7d8f21442b..aa62bcc8daf 100644
--- a/lib/AsmParser/LLParser.h
+++ b/lib/AsmParser/LLParser.h
@@ -226,7 +226,7 @@ namespace llvm {
     }
     bool ParseOptionalVisibility(unsigned &Visibility);
     bool ParseOptionalDLLStorageClass(unsigned &DLLStorageClass);
-    bool ParseOptionalCallingConv(CallingConv::ID &CC);
+    bool ParseOptionalCallingConv(unsigned &CC);
     bool ParseOptionalAlignment(unsigned &Alignment);
     bool ParseOptionalDereferenceableBytes(uint64_t &Bytes);
     bool ParseScopeAndOrdering(bool isAtomic, SynchronizationScope &Scope,