Add Windows Control Flow Guard checks (/guard:cf).

Summary:
A new function pass (Transforms/CFGuard/CFGuard.cpp) inserts CFGuard checks on
indirect function calls, using either the check mechanism (X86, ARM, AArch64) or
or the dispatch mechanism (X86-64). The check mechanism requires a new calling
convention for the supported targets. The dispatch mechanism adds the target as
an operand bundle, which is processed by SelectionDAG. Another pass
(CodeGen/CFGuardLongjmp.cpp) identifies and emits valid longjmp targets, as
required by /guard:cf. This feature is enabled using the `cfguard` CC1 option.

Reviewers: thakis, rnk, theraven, pcc

Subscribers: ychen, hans, metalcanine, dmajor, tomrittervg, alex, mehdi_amini, mgorny, javed.absar, kristof.beyls, hiraditya, steven_wu, dexonsmith, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D65761

1 files changed, 2 insertions, 0 deletions

diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 664ef8d4844..41e1d0bd889 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -1921,6 +1921,7 @@ void LLParser::ParseOptionalDLLStorageClass(unsigned &Res) {
 ///   ::= 'fastcc'
 ///   ::= 'intel_ocl_bicc'
 ///   ::= 'coldcc'
+///   ::= 'cfguard_checkcc'
 ///   ::= 'x86_stdcallcc'
 ///   ::= 'x86_fastcallcc'
 ///   ::= 'x86_thiscallcc'
@@ -1965,6 +1966,7 @@ bool LLParser::ParseOptionalCallingConv(unsigned &CC) {
   case lltok::kw_ccc:            CC = CallingConv::C; break;
   case lltok::kw_fastcc:         CC = CallingConv::Fast; break;
   case lltok::kw_coldcc:         CC = CallingConv::Cold; break;
+  case lltok::kw_cfguard_checkcc: CC = CallingConv::CFGuard_Check; break;
   case lltok::kw_x86_stdcallcc:  CC = CallingConv::X86_StdCall; break;
   case lltok::kw_x86_fastcallcc: CC = CallingConv::X86_FastCall; break;
   case lltok::kw_x86_regcallcc:  CC = CallingConv::X86_RegCall; break;