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/Bitcode/Reader/BitcodeReader.cpp | 3 +++ 1 file changed, 3 insertions(+) (limited to 'llvm/lib/Bitcode/Reader/BitcodeReader.cpp') diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp index 582298136ae..74b57a86b8b 100644 --- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp +++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp @@ -1160,6 +1160,7 @@ static uint64_t getRawAttributeMask(Attribute::AttrKind Val) { case Attribute::Speculatable: return 1ULL << 54; case Attribute::StrictFP: return 1ULL << 55; case Attribute::SanitizeHWAddress: return 1ULL << 56; + case Attribute::NoCfCheck: return 1ULL << 57; case Attribute::Dereferenceable: llvm_unreachable("dereferenceable attribute not supported in raw format"); break; @@ -1338,6 +1339,8 @@ static Attribute::AttrKind getAttrFromCode(uint64_t Code) { return Attribute::NoRedZone; case bitc::ATTR_KIND_NO_RETURN: return Attribute::NoReturn; + case bitc::ATTR_KIND_NOCF_CHECK: + return Attribute::NoCfCheck; case bitc::ATTR_KIND_NO_UNWIND: return Attribute::NoUnwind; case bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE: -- cgit v1.2.3