commit fdd72fd5225dedb4431473fb3ac7b3d45fc8ed00
author Oren Ben Simhon <oren.ben.simhon@intel.com> Sat Mar 17 13:29:46 2018 +0000
committer Oren Ben Simhon <oren.ben.simhon@intel.com> Sat Mar 17 13:29:46 2018 +0000
tree b1819bd5c756e40209091ea07d752efab4cf83ac
parent dbcf1bf503880084e33e57e9fb916a66703d18d7

[X86] Added support for nocf_check attribute for indirect Branch Tracking

X86 Supports Indirect Branch Tracking (IBT) as part of Control-Flow Enforcement Technology (CET).
IBT instruments ENDBR instructions used to specify valid targets of indirect call / jmp.
The `nocf_check` attribute has two roles in the context of X86 IBT technology:
	1. Appertains to a function - do not add ENDBR instruction at the beginning of the function.
	2. Appertains to a function pointer - do not track the target function of this pointer by adding nocf_check prefix to the indirect-call instruction.

This patch implements `nocf_check` context for Indirect Branch Tracking.
It also auto generates `nocf_check` prefixes before indirect branchs to jump tables that are guarded by range checks.

Differential Revision: https://reviews.llvm.org/D41879

llvm-svn: 327767

llvm/lib/AsmParser/LLLexer.cpp

diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index d8be4ad..e315760 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -648,6 +648,7 @@
   KEYWORD(nonnull);
   KEYWORD(noredzone);
   KEYWORD(noreturn);
+  KEYWORD(nocf_check);
   KEYWORD(nounwind);
   KEYWORD(optnone);
   KEYWORD(optsize);

llvm/lib/AsmParser/LLParser.cpp

diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 29e6b07..1c607de 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -1131,6 +1131,7 @@
     case lltok::kw_nonlazybind: B.addAttribute(Attribute::NonLazyBind); break;
     case lltok::kw_noredzone: B.addAttribute(Attribute::NoRedZone); break;
     case lltok::kw_noreturn: B.addAttribute(Attribute::NoReturn); break;
+    case lltok::kw_nocf_check: B.addAttribute(Attribute::NoCfCheck); break;
     case lltok::kw_norecurse: B.addAttribute(Attribute::NoRecurse); break;
     case lltok::kw_nounwind: B.addAttribute(Attribute::NoUnwind); break;
     case lltok::kw_optnone: B.addAttribute(Attribute::OptimizeNone); break;
@@ -1468,6 +1469,7 @@
     case lltok::kw_nonlazybind:
     case lltok::kw_noredzone:
     case lltok::kw_noreturn:
+    case lltok::kw_nocf_check:
     case lltok::kw_nounwind:
     case lltok::kw_optnone:
     case lltok::kw_optsize:
@@ -1561,6 +1563,7 @@
     case lltok::kw_nonlazybind:
     case lltok::kw_noredzone:
     case lltok::kw_noreturn:
+    case lltok::kw_nocf_check:
     case lltok::kw_nounwind:
     case lltok::kw_optnone:
     case lltok::kw_optsize:

llvm/lib/AsmParser/LLToken.h

diff --git a/llvm/lib/AsmParser/LLToken.h b/llvm/lib/AsmParser/LLToken.h
index ad826cc..3ef44d4 100644
--- a/llvm/lib/AsmParser/LLToken.h
+++ b/llvm/lib/AsmParser/LLToken.h
@@ -199,6 +199,7 @@
   kw_nonnull,
   kw_noredzone,
   kw_noreturn,
+  kw_nocf_check,
   kw_nounwind,
   kw_optnone,
   kw_optsize,