From fdd72fd5225dedb4431473fb3ac7b3d45fc8ed00 Mon Sep 17 00:00:00 2001 From: Oren Ben Simhon Date: Sat, 17 Mar 2018 13:29:46 +0000 Subject: [X86] Added support for nocf_check attribute for indirect Branch Tracking MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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/IR/Attributes.cpp | 2 ++ 1 file changed, 2 insertions(+) (limited to 'llvm/lib/IR/Attributes.cpp') diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp index 30216bcde68..0aea24f22c0 100644 --- a/llvm/lib/IR/Attributes.cpp +++ b/llvm/lib/IR/Attributes.cpp @@ -299,6 +299,8 @@ std::string Attribute::getAsString(bool InAttrGrp) const { return "noredzone"; if (hasAttribute(Attribute::NoReturn)) return "noreturn"; + if (hasAttribute(Attribute::NoCfCheck)) + return "nocf_check"; if (hasAttribute(Attribute::NoRecurse)) return "norecurse"; if (hasAttribute(Attribute::NoUnwind)) -- cgit v1.2.3