Rollup merge of rust-lang#91675 - ivanloz:memtagsan, r=nagisa

Add MemTagSanitizer Support

Add support for the LLVM [MemTagSanitizer](https://llvm.org/docs/MemTagSanitizer.html).

On hardware which supports it (see caveats below), the MemTagSanitizer can catch bugs similar to AddressSanitizer and HardwareAddressSanitizer, but with lower overhead.

On a tag mismatch, a SIGSEGV is signaled with code SEGV_MTESERR / SEGV_MTEAERR.

# Usage

`-Zsanitizer=memtag -C target-feature="+mte"`

# Comments/Caveats

* MemTagSanitizer is only supported on AArch64 targets with hardware support
* Requires `-C target-feature="+mte"`
* LLVM MemTagSanitizer currently only performs stack tagging.

# TODO

* Tests
* Example

Author: matthiaskrgr

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -55,6 +55,19 @@ pub fn sanitize<'ll>(cx: &CodegenCx<'ll, '_>, no_sanitize: SanitizerSet, llfn: &
     if enabled.contains(SanitizerSet::HWADDRESS) {
         llvm::Attribute::SanitizeHWAddress.apply_llfn(Function, llfn);
     }
+    if enabled.contains(SanitizerSet::MEMTAG) {
+        // Check to make sure the mte target feature is actually enabled.
+        let sess = cx.tcx.sess;
+        let features = llvm_util::llvm_global_features(sess).join(",");
+        let mte_feature_enabled = features.rfind("+mte");
+        let mte_feature_disabled = features.rfind("-mte");
+
+        if mte_feature_enabled.is_none() || (mte_feature_disabled > mte_feature_enabled) {
+            sess.err("`-Zsanitizer=memtag` requires `-Ctarget-feature=+mte`");
+        }
+
+        llvm::Attribute::SanitizeMemTag.apply_llfn(Function, llfn);
+    }
 }
 
 /// Tell LLVM to emit or not emit the information necessary to unwind the stack for the function.

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -190,6 +190,7 @@ pub enum Attribute {
     StackProtectStrong = 31,
     StackProtect = 32,
     NoUndef = 33,
+    SanitizeMemTag = 34,
 }
 
 /// LLVMIntPredicate

compiler/rustc_llvm/llvm-wrapper/LLVMWrapper.h

@@ -83,6 +83,7 @@ enum LLVMRustAttribute {
   StackProtectStrong = 31,
   StackProtect = 32,
   NoUndef = 33,
+  SanitizeMemTag = 34,
 };
 
 typedef struct OpaqueRustString *RustStringRef;

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -226,6 +226,8 @@ static Attribute::AttrKind fromRust(LLVMRustAttribute Kind) {
     return Attribute::StackProtect;
   case NoUndef:
     return Attribute::NoUndef;
+  case SanitizeMemTag:
+    return Attribute::SanitizeMemTag;
   }
   report_fatal_error("bad AttributeKind");
 }

compiler/rustc_session/src/options.rs

@@ -376,7 +376,7 @@ mod desc {
     pub const parse_panic_strategy: &str = "either `unwind` or `abort`";
     pub const parse_opt_panic_strategy: &str = parse_panic_strategy;
     pub const parse_relro_level: &str = "one of: `full`, `partial`, or `off`";
-    pub const parse_sanitizers: &str = "comma separated list of sanitizers: `address`, `cfi`, `hwaddress`, `leak`, `memory` or `thread`";
+    pub const parse_sanitizers: &str = "comma separated list of sanitizers: `address`, `cfi`, `hwaddress`, `leak`, `memory`, `memtag`, or `thread`";
     pub const parse_sanitizer_memory_track_origins: &str = "0, 1, or 2";
     pub const parse_cfguard: &str =
         "either a boolean (`yes`, `no`, `on`, `off`, etc), `checks`, or `nochecks`";
@@ -639,6 +639,7 @@ mod parse {
                     "cfi" => SanitizerSet::CFI,
                     "leak" => SanitizerSet::LEAK,
                     "memory" => SanitizerSet::MEMORY,
+                    "memtag" => SanitizerSet::MEMTAG,
                     "thread" => SanitizerSet::THREAD,
                     "hwaddress" => SanitizerSet::HWADDRESS,
                     _ => return false,

compiler/rustc_span/src/symbol.rs

@@ -876,6 +876,7 @@ symbols! {
         mem_zeroed,
         member_constraints,
         memory,
+        memtag,
         message,
         meta,
         metadata_type,

compiler/rustc_target/src/spec/aarch64_linux_android.rs

@@ -14,7 +14,9 @@ pub fn target() -> Target {
             // As documented in https://developer.android.com/ndk/guides/cpu-features.html
             // the neon (ASIMD) and FP must exist on all android aarch64 targets.
             features: "+neon,+fp-armv8".to_string(),
-            supported_sanitizers: SanitizerSet::CFI | SanitizerSet::HWADDRESS,
+            supported_sanitizers: SanitizerSet::CFI
+                | SanitizerSet::HWADDRESS
+                | SanitizerSet::MEMTAG,
             ..super::android_base::opts()
         },
     }

compiler/rustc_target/src/spec/aarch64_unknown_linux_gnu.rs

@@ -14,6 +14,7 @@ pub fn target() -> Target {
                 | SanitizerSet::CFI
                 | SanitizerSet::LEAK
                 | SanitizerSet::MEMORY
+                | SanitizerSet::MEMTAG
                 | SanitizerSet::THREAD
                 | SanitizerSet::HWADDRESS,
             ..super::linux_gnu_base::opts()

compiler/rustc_target/src/spec/mod.rs

@@ -606,6 +606,7 @@ bitflags::bitflags! {
         const THREAD  = 1 << 3;
         const HWADDRESS = 1 << 4;
         const CFI     = 1 << 5;
+        const MEMTAG  = 1 << 6;
     }
 }
 
@@ -619,6 +620,7 @@ impl SanitizerSet {
             SanitizerSet::CFI => "cfi",
             SanitizerSet::LEAK => "leak",
             SanitizerSet::MEMORY => "memory",
+            SanitizerSet::MEMTAG => "memtag",
             SanitizerSet::THREAD => "thread",
             SanitizerSet::HWADDRESS => "hwaddress",
             _ => return None,
@@ -652,6 +654,7 @@ impl IntoIterator for SanitizerSet {
             SanitizerSet::CFI,
             SanitizerSet::LEAK,
             SanitizerSet::MEMORY,
+            SanitizerSet::MEMTAG,
             SanitizerSet::THREAD,
             SanitizerSet::HWADDRESS,
         ]
@@ -1883,6 +1886,7 @@ impl Target {
                                 Some("cfi") => SanitizerSet::CFI,
                                 Some("leak") => SanitizerSet::LEAK,
                                 Some("memory") => SanitizerSet::MEMORY,
+                                Some("memtag") => SanitizerSet::MEMTAG,
                                 Some("thread") => SanitizerSet::THREAD,
                                 Some("hwaddress") => SanitizerSet::HWADDRESS,
                                 Some(s) => return Err(format!("unknown sanitizer {}", s)),

compiler/rustc_typeck/src/collect.rs

@@ -3009,14 +3009,16 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
                         codegen_fn_attrs.no_sanitize |= SanitizerSet::CFI;
                     } else if item.has_name(sym::memory) {
                         codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMORY;
+                    } else if item.has_name(sym::memtag) {
+                        codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMTAG;
                     } else if item.has_name(sym::thread) {
                         codegen_fn_attrs.no_sanitize |= SanitizerSet::THREAD;
                     } else if item.has_name(sym::hwaddress) {
                         codegen_fn_attrs.no_sanitize |= SanitizerSet::HWADDRESS;
                     } else {
                         tcx.sess
                             .struct_span_err(item.span(), "invalid argument for `no_sanitize`")
-                            .note("expected one of: `address`, `hwaddress`, `memory` or `thread`")
+                            .note("expected one of: `address`, `cfi`, `hwaddress`, `memory`, `memtag`, or `thread`")
                             .emit();
                     }
                 }