ARM MTE stack sanitizer.

Add "memtag" sanitizer that detects and mitigates stack memory issues
using armv8.5 Memory Tagging Extension.

It is similar in principle to HWASan, which is a software implementation
of the same idea, but there are enough differencies to warrant a new
sanitizer type IMHO. It is also expected to have very different
performance properties.

The new sanitizer does not have a runtime library (it may grow one
later, along with a "debugging" mode). Similar to SafeStack and
StackProtector, the instrumentation pass (in a follow up change) will be
inserted in all cases, but will only affect functions marked with the
new sanitize_memtag attribute.

Reviewers: pcc, hctim, vitalybuka, ostannard

Subscribers: srhines, mehdi_amini, javed.absar, kristof.beyls, hiraditya, cryptoad, steven_wu, dexonsmith, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D64169

llvm-svn: 366123

1 files changed, 4 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGDeclCXX.cpp b/clang/lib/CodeGen/CGDeclCXX.cpp
index 1c7c6fb5413..7a0605b8450 100644
--- a/clang/lib/CodeGen/CGDeclCXX.cpp
+++ b/clang/lib/CodeGen/CGDeclCXX.cpp
@@ -369,6 +369,10 @@ llvm::Function *CodeGenModule::CreateGlobalInitOrDestructFunction(
       !isInSanitizerBlacklist(SanitizerKind::KernelHWAddress, Fn, Loc))
     Fn->addFnAttr(llvm::Attribute::SanitizeHWAddress);
 
+  if (getLangOpts().Sanitize.has(SanitizerKind::MemTag) &&
+      !isInSanitizerBlacklist(SanitizerKind::MemTag, Fn, Loc))
+    Fn->addFnAttr(llvm::Attribute::SanitizeMemTag);
+
   if (getLangOpts().Sanitize.has(SanitizerKind::Thread) &&
       !isInSanitizerBlacklist(SanitizerKind::Thread, Fn, Loc))
     Fn->addFnAttr(llvm::Attribute::SanitizeThread);