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, 8 insertions, 2 deletions

diff --git a/clang/lib/Driver/SanitizerArgs.cpp b/clang/lib/Driver/SanitizerArgs.cpp
index 8d4b9fc85de..9132faa9176 100644
--- a/clang/lib/Driver/SanitizerArgs.cpp
+++ b/clang/lib/Driver/SanitizerArgs.cpp
@@ -40,7 +40,8 @@ static const SanitizerMask NeedsUnwindTables =
 static const SanitizerMask SupportsCoverage =
     SanitizerKind::Address | SanitizerKind::HWAddress |
     SanitizerKind::KernelAddress | SanitizerKind::KernelHWAddress |
-    SanitizerKind::Memory | SanitizerKind::KernelMemory | SanitizerKind::Leak |
+    SanitizerKind::MemTag | SanitizerKind::Memory |
+    SanitizerKind::KernelMemory | SanitizerKind::Leak |
     SanitizerKind::Undefined | SanitizerKind::Integer |
     SanitizerKind::ImplicitConversion | SanitizerKind::Nullability |
     SanitizerKind::DataFlow | SanitizerKind::Fuzzer |
@@ -122,6 +123,7 @@ static void addDefaultBlacklists(const Driver &D, SanitizerMask Kinds,
     SanitizerMask Mask;
   } Blacklists[] = {{"asan_blacklist.txt", SanitizerKind::Address},
                     {"hwasan_blacklist.txt", SanitizerKind::HWAddress},
+                    {"memtag_blacklist.txt", SanitizerKind::MemTag},
                     {"msan_blacklist.txt", SanitizerKind::Memory},
                     {"tsan_blacklist.txt", SanitizerKind::Thread},
                     {"dfsan_abilist.txt", SanitizerKind::DataFlow},
@@ -420,7 +422,11 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
                      SanitizerKind::Address | SanitizerKind::HWAddress |
                          SanitizerKind::Leak | SanitizerKind::Thread |
                          SanitizerKind::Memory | SanitizerKind::KernelAddress |
-                         SanitizerKind::Scudo | SanitizerKind::SafeStack)};
+                         SanitizerKind::Scudo | SanitizerKind::SafeStack),
+      std::make_pair(SanitizerKind::MemTag,
+                     SanitizerKind::Address | SanitizerKind::KernelAddress |
+                         SanitizerKind::HWAddress |
+                         SanitizerKind::KernelHWAddress)};
   // Enable toolchain specific default sanitizers if not explicitly disabled.
   SanitizerMask Default = TC.getDefaultSanitizers() & ~AllRemove;