Merge #921

921: Apply TBAA metadata in the LLVM backend. r=nlewycky a=nlewycky

# Description
Inform LLVM that the pointers to memory, globals, locals, etc., are distinct.

# Review

- [x] Add a short description of the the change to the CHANGELOG.md file


Co-authored-by: Nick Lewycky <nick@wasmer.io>
Co-authored-by: nlewycky <nick@wasmer.io>

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## **[Unreleased]**
 
+- [#921](https://github.com/wasmerio/wasmer/pull/921) In LLVM backend, annotate all memory accesses with TBAA metadata.
 - [#883](https://github.com/wasmerio/wasmer/pull/883) Allow floating point operations to have arbitrary inputs, even including SNaNs.
 - [#856](https://github.com/wasmerio/wasmer/pull/856) Expose methods in the runtime C API to get a WASI import object
 

Cargo.lock

@@ -120,7 +120,7 @@ dependencies = [
  "serde_json 1.0.41 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "toml 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "toml 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -188,7 +188,7 @@ dependencies = [
  "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "failure_derive 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "target-lexicon 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -275,7 +275,7 @@ dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "memoffset 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memoffset 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "scopeguard 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -494,7 +494,15 @@ name = "heck"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "unicode-segmentation 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-segmentation 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "hermit-abi"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -514,7 +522,7 @@ dependencies = [
 [[package]]
 name = "inkwell"
 version = "0.1.0"
-source = "git+https://github.com/wasmerio/inkwell?branch=llvm8-0#5ae21b51d9dd20a63e4431b06e3beb7a42d6ceb8"
+source = "git+https://github.com/wasmerio/inkwell?branch=llvm8-0#10d180807ce6e621ae13d74001bf5677b0e1f179"
 dependencies = [
  "either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "enum-methods 0.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -528,7 +536,7 @@ dependencies = [
 [[package]]
 name = "inkwell_internal_macros"
 version = "0.1.0"
-source = "git+https://github.com/wasmerio/inkwell?branch=llvm8-0#5ae21b51d9dd20a63e4431b06e3beb7a42d6ceb8"
+source = "git+https://github.com/wasmerio/inkwell?branch=llvm8-0#10d180807ce6e621ae13d74001bf5677b0e1f179"
 dependencies = [
  "cargo_toml 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -653,7 +661,7 @@ dependencies = [
 
 [[package]]
 name = "memoffset"
-version = "0.5.1"
+version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -686,9 +694,10 @@ dependencies = [
 
 [[package]]
 name = "num_cpus"
-version = "1.10.1"
+version = "1.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
+ "hermit-abi 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -748,7 +757,7 @@ dependencies = [
  "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -914,7 +923,7 @@ dependencies = [
  "crossbeam-queue 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "num_cpus 1.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1067,7 +1076,7 @@ dependencies = [
 
 [[package]]
 name = "smallvec"
-version = "0.6.11"
+version = "0.6.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -1223,7 +1232,7 @@ dependencies = [
 
 [[package]]
 name = "toml"
-version = "0.5.4"
+version = "0.5.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "serde 1.0.102 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1258,7 +1267,7 @@ dependencies = [
 
 [[package]]
 name = "unicode-segmentation"
-version = "1.3.0"
+version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -1385,7 +1394,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cranelift-codegen 0.44.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "target-lexicon 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1458,7 +1467,7 @@ dependencies = [
  "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "wabt 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasmer-runtime-core 0.9.0",
  "wasmparser 0.39.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1533,7 +1542,7 @@ dependencies = [
  "serde-bench 0.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_bytes 0.11.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.102 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasmparser 0.39.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1559,7 +1568,7 @@ dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
  "nix 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasmer-runtime-core 0.9.0",
 ]
 
@@ -1716,6 +1725,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum glob 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
 "checksum goblin 0.0.24 (registry+https://github.com/rust-lang/crates.io-index)" = "e3fa261d919c1ae9d1e4533c4a2f99e10938603c4208d56c05bec7a872b661b0"
 "checksum heck 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "20564e78d53d2bb135c343b3f47714a56af2061f1c928fdb541dc7b9fdd94205"
+"checksum hermit-abi 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "307c3c9f937f38e3534b1d6447ecf090cafcc9744e4a6360e8b037b2cf5af120"
 "checksum hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "805026a5d0141ffc30abb3be3173848ad46a1b1664fe632428479619a3644d77"
 "checksum indexmap 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712d7b3ea5827fcb9d4fda14bf4da5f136f0db2ae9c8f4bd4e2d1c6fde4e6db2"
 "checksum inkwell 0.1.0 (git+https://github.com/wasmerio/inkwell?branch=llvm8-0)" = "<none>"
@@ -1734,11 +1744,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "88579771288728879b57485cc7d6b07d648c9f0141eb955f8ab7f9d45394468e"
 "checksum memmap 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e2ffa2c986de11a9df78620c01eeaaf27d94d3ff02bf81bfcca953102dd0c6ff"
 "checksum memmap 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6585fd95e7bb50d6cc31e20d4cf9afb4e2ba16c5846fc76793f11218da9c475b"
-"checksum memoffset 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ce6075db033bbbb7ee5a0bbd3a3186bbae616f57fb001c485c7ff77955f8177f"
+"checksum memoffset 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "4a85c1a8c329f11437034d7313dca647c79096523533a1c79e86f1d0f657c7cc"
 "checksum nix 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3b2e0b4f3320ed72aaedb9a5ac838690a8047c7b275da22711fddff4f8a14229"
 "checksum nodrop 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)" = "72ef4a56884ca558e5ddb05a1d1e7e1bfd9a68d9ed024c21704cc98872dae1bb"
 "checksum num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "6ba9a427cfca2be13aa6f6403b0b7e7368fe982bfa16fccc450ce74c46cd9b32"
-"checksum num_cpus 1.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "bcef43580c035376c0705c42792c294b66974abbfd2789b511784023f71f3273"
+"checksum num_cpus 1.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "155394f924cdddf08149da25bfb932d226b4a593ca7468b08191ff6335941af5"
 "checksum owning_ref 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "cdf84f41639e037b484f93433aa3897863b561ed65c6e59c7073d7c561710f37"
 "checksum page_size 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "f89ef58b3d32420dbd1a43d2f38ae92f6239ef12bb556ab09ca55445f5a67242"
 "checksum parking_lot 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f842b1982eb6c2fe34036a4fbfb06dd185a3f5c8edfaacdf7d1ea10b07de6252"
@@ -1781,7 +1791,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum serde_bytes 0.11.2 (registry+https://github.com/rust-lang/crates.io-index)" = "45af0182ff64abaeea290235eb67da3825a576c5d53e642c4d5b652e12e6effc"
 "checksum serde_derive 1.0.102 (registry+https://github.com/rust-lang/crates.io-index)" = "ca13fc1a832f793322228923fbb3aba9f3f44444898f835d31ad1b74fa0a2bf8"
 "checksum serde_json 1.0.41 (registry+https://github.com/rust-lang/crates.io-index)" = "2f72eb2a68a7dc3f9a691bfda9305a1c017a6215e5a4545c258500d2099a37c2"
-"checksum smallvec 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)" = "cefaa50e76a6f10b86f36e640eb1739eafbd4084865067778463913e43a77ff3"
+"checksum smallvec 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)" = "533e29e15d0748f28afbaf4ff7cab44d73e483a8e50b38c40bd13b7f3d48f542"
 "checksum stable_deref_trait 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dba1a27d3efae4351c8051072d619e3ade2820635c3958d826bfea39d59b54c8"
 "checksum strsim 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 "checksum structopt 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6d4f66a4c0ddf7aee4677995697366de0749b0139057342eccbb609b12d0affc"
@@ -1799,11 +1809,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum time 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)" = "db8dcfca086c1143c9270ac42a2bbd8a7ee477b78ac8e45b19abfb0cbede4b6f"
 "checksum tinytemplate 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "4574b75faccaacddb9b284faecdf0b544b80b6b294f3d062d325c5726a209c20"
 "checksum toml 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)" = "758664fc71a3a69038656bee8b6be6477d2a6c315a6b81f7081f591bffa4111f"
-"checksum toml 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)" = "c04dffffeac90885436d23c692517bb5b8b3f8863e4afc15023628d067d667b7"
+"checksum toml 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)" = "01d1404644c8b12b16bfcffa4322403a91a451584daaaa7c28d3152e6cbc98cf"
 "checksum typenum 1.11.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6d2783fe2d6b8c1101136184eb41be8b1ad379e4657050b8aaff0c79ee7575f9"
 "checksum typetag 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "6ebb2c484029d695fb68a06d80e1536c68d491b3e0cf874c66abed255e831cfe"
 "checksum typetag-impl 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "b63fd4799e4d0ec5cf0b055ebb8e2c3a657bbf76a84f6edc77ca60780e000204"
-"checksum unicode-segmentation 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1967f4cdfc355b37fd76d2a954fb2ed3871034eb4f26d60537d88795cfc332a9"
+"checksum unicode-segmentation 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "49f5526225fd8b77342d5986ab5f6055552e9c0776193b5b63fd53b46debfad7"
 "checksum unicode-width 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "7007dbd421b92cc6e28410fe7362e2e0a2503394908f417b68ec8d1c364c4e20"
 "checksum unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f860d7d29cf02cb2f3f359fd35991af3d30bac52c57d265a3c461074cb4dc"
 "checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"

lib/llvm-backend/src/backend.rs

@@ -11,12 +11,14 @@ use inkwell::{
 use libc::c_char;
 use std::{
     any::Any,
+    cell::RefCell,
     ffi::{c_void, CString},
     fs::File,
     io::Write,
     mem,
     ops::Deref,
     ptr::{self, NonNull},
+    rc::Rc,
     slice, str,
     sync::{Arc, Once},
 };
@@ -169,14 +171,14 @@ pub struct LLVMBackend {
 
 impl LLVMBackend {
     pub fn new(
-        module: Module,
+        module: Rc<RefCell<Module>>,
         _intrinsics: Intrinsics,
         _stackmaps: &StackmapRegistry,
         _module_info: &ModuleInfo,
         target_machine: &TargetMachine,
     ) -> (Self, LLVMCache) {
         let memory_buffer = target_machine
-            .write_to_memory_buffer(&module, FileType::Object)
+            .write_to_memory_buffer(&module.borrow_mut(), FileType::Object)
             .unwrap();
         let mem_buf_slice = memory_buffer.as_slice();
 

lib/llvm-backend/src/intrinsics.rs

@@ -7,12 +7,15 @@ use inkwell::{
         BasicType, FloatType, FunctionType, IntType, PointerType, StructType, VectorType, VoidType,
     },
     values::{
-        BasicValue, BasicValueEnum, FloatValue, FunctionValue, IntValue, PointerValue, VectorValue,
+        BasicValue, BasicValueEnum, FloatValue, FunctionValue, InstructionValue, IntValue,
+        MetadataValue, PointerValue, VectorValue,
     },
     AddressSpace,
 };
+use std::cell::RefCell;
 use std::collections::HashMap;
 use std::marker::PhantomData;
+use std::rc::Rc;
 use wasmer_runtime_core::{
     memory::MemoryType,
     module::ModuleInfo,
@@ -658,7 +661,12 @@ impl<'a> CtxType<'a> {
         ptr
     }
 
-    pub fn memory(&mut self, index: MemoryIndex, intrinsics: &Intrinsics) -> MemoryCache {
+    pub fn memory(
+        &mut self,
+        index: MemoryIndex,
+        intrinsics: &Intrinsics,
+        module: Rc<RefCell<Module>>,
+    ) -> MemoryCache {
         let (cached_memories, info, ctx_ptr_value, cache_builder) = (
             &mut self.cached_memories,
             self.info,
@@ -667,7 +675,7 @@ impl<'a> CtxType<'a> {
         );
 
         *cached_memories.entry(index).or_insert_with(|| {
-            let (memory_array_ptr_ptr, index, memory_type, minimum, maximum) =
+            let (memory_array_ptr_ptr, index, memory_type, minimum, maximum, field_name) =
                 match index.local_or_import(info) {
                     LocalOrImport::Local(local_mem_index) => (
                         unsafe {
@@ -681,6 +689,7 @@ impl<'a> CtxType<'a> {
                         info.memories[local_mem_index].memory_type(),
                         info.memories[local_mem_index].minimum,
                         info.memories[local_mem_index].maximum,
+                        "context_field_ptr_to_local_memory",
                     ),
                     LocalOrImport::Import(import_mem_index) => (
                         unsafe {
@@ -694,12 +703,20 @@ impl<'a> CtxType<'a> {
                         info.imported_memories[import_mem_index].1.memory_type(),
                         info.imported_memories[import_mem_index].1.minimum,
                         info.imported_memories[import_mem_index].1.maximum,
+                        "context_field_ptr_to_imported_memory",
                     ),
                 };
 
             let memory_array_ptr = cache_builder
                 .build_load(memory_array_ptr_ptr, "memory_array_ptr")
                 .into_pointer_value();
+            tbaa_label(
+                module.clone(),
+                intrinsics,
+                field_name,
+                memory_array_ptr.as_instruction_value().unwrap(),
+                None,
+            );
             let const_index = intrinsics.i32_ty.const_int(index, false);
             let memory_ptr_ptr = unsafe {
                 cache_builder.build_in_bounds_gep(
@@ -711,6 +728,13 @@ impl<'a> CtxType<'a> {
             let memory_ptr = cache_builder
                 .build_load(memory_ptr_ptr, "memory_ptr")
                 .into_pointer_value();
+            tbaa_label(
+                module.clone(),
+                intrinsics,
+                "memory_ptr",
+                memory_ptr.as_instruction_value().unwrap(),
+                Some(index as u32),
+            );
 
             let (ptr_to_base_ptr, ptr_to_bounds) = unsafe {
                 (
@@ -726,16 +750,34 @@ impl<'a> CtxType<'a> {
                     minimum,
                     maximum,
                 },
-                MemoryType::Static | MemoryType::SharedStatic => MemoryCache::Static {
+                MemoryType::Static | MemoryType::SharedStatic => {
-                    base_ptr: cache_builder
+                    let base_ptr = cache_builder
                         .build_load(ptr_to_base_ptr, "base")
-                        .into_pointer_value(),
+                        .into_pointer_value();
-                    bounds: cache_builder
+                    let bounds = cache_builder
                         .build_load(ptr_to_bounds, "bounds")
-                        .into_int_value(),
+                        .into_int_value();
-                    minimum,
+                    tbaa_label(
-                    maximum,
+                        module.clone(),
-                },
+                        intrinsics,
+                        "static_memory_base",
+                        base_ptr.as_instruction_value().unwrap(),
+                        Some(index as u32),
+                    );
+                    tbaa_label(
+                        module.clone(),
+                        intrinsics,
+                        "static_memory_bounds",
+                        bounds.as_instruction_value().unwrap(),
+                        Some(index as u32),
+                    );
+                    MemoryCache::Static {
+                        base_ptr,
+                        bounds,
+                        minimum,
+                        maximum,
+                    }
+                }
             }
         })
     }
@@ -744,6 +786,7 @@ impl<'a> CtxType<'a> {
         &mut self,
         index: TableIndex,
         intrinsics: &Intrinsics,
+        module: Rc<RefCell<Module>>,
     ) -> (PointerValue, PointerValue) {
         let (cached_tables, info, ctx_ptr_value, cache_builder) = (
             &mut self.cached_tables,
@@ -756,7 +799,7 @@ impl<'a> CtxType<'a> {
             ptr_to_base_ptr,
             ptr_to_bounds,
         } = *cached_tables.entry(index).or_insert_with(|| {
-            let (table_array_ptr_ptr, index) = match index.local_or_import(info) {
+            let (table_array_ptr_ptr, index, field_name) = match index.local_or_import(info) {
                 LocalOrImport::Local(local_table_index) => (
                     unsafe {
                         cache_builder.build_struct_gep(
@@ -766,6 +809,7 @@ impl<'a> CtxType<'a> {
                         )
                     },
                     local_table_index.index() as u64,
+                    "context_field_ptr_to_local_table",
                 ),
                 LocalOrImport::Import(import_table_index) => (
                     unsafe {
@@ -776,12 +820,20 @@ impl<'a> CtxType<'a> {
                         )
                     },
                     import_table_index.index() as u64,
+                    "context_field_ptr_to_import_table",
                 ),
             };
 
             let table_array_ptr = cache_builder
                 .build_load(table_array_ptr_ptr, "table_array_ptr")
                 .into_pointer_value();
+            tbaa_label(
+                module.clone(),
+                intrinsics,
+                field_name,
+                table_array_ptr.as_instruction_value().unwrap(),
+                None,
+            );
             let const_index = intrinsics.i32_ty.const_int(index, false);
             let table_ptr_ptr = unsafe {
                 cache_builder.build_in_bounds_gep(table_array_ptr, &[const_index], "table_ptr_ptr")
@@ -789,6 +841,13 @@ impl<'a> CtxType<'a> {
             let table_ptr = cache_builder
                 .build_load(table_ptr_ptr, "table_ptr")
                 .into_pointer_value();
+            tbaa_label(
+                module.clone(),
+                intrinsics,
+                "table_ptr",
+                table_array_ptr.as_instruction_value().unwrap(),
+                Some(index as u32),
+            );
 
             let (ptr_to_base_ptr, ptr_to_bounds) = unsafe {
                 (
@@ -810,15 +869,30 @@ impl<'a> CtxType<'a> {
         &mut self,
         index: TableIndex,
         intrinsics: &Intrinsics,
+        module: Rc<RefCell<Module>>,
         builder: &Builder,
     ) -> (PointerValue, IntValue) {
-        let (ptr_to_base_ptr, ptr_to_bounds) = self.table_prepare(index, intrinsics);
+        let (ptr_to_base_ptr, ptr_to_bounds) =
-        (
+            self.table_prepare(index, intrinsics, module.clone());
-            builder
+        let base_ptr = builder
-                .build_load(ptr_to_base_ptr, "base_ptr")
+            .build_load(ptr_to_base_ptr, "base_ptr")
-                .into_pointer_value(),
+            .into_pointer_value();
-            builder.build_load(ptr_to_bounds, "bounds").into_int_value(),
+        let bounds = builder.build_load(ptr_to_bounds, "bounds").into_int_value();
-        )
+        tbaa_label(
+            module.clone(),
+            intrinsics,
+            "table_base_ptr",
+            base_ptr.as_instruction_value().unwrap(),
+            Some(index.index() as u32),
+        );
+        tbaa_label(
+            module.clone(),
+            intrinsics,
+            "table_bounds",
+            bounds.as_instruction_value().unwrap(),
+            Some(index.index() as u32),
+        );
+        (base_ptr, bounds)
     }
 
     pub fn local_func(
@@ -826,6 +900,7 @@ impl<'a> CtxType<'a> {
         index: LocalFuncIndex,
         fn_ty: FunctionType,
         intrinsics: &Intrinsics,
+        module: Rc<RefCell<Module>>,
         builder: &Builder,
     ) -> PointerValue {
         let local_func_array_ptr_ptr = unsafe {
@@ -838,6 +913,13 @@ impl<'a> CtxType<'a> {
         let local_func_array_ptr = builder
             .build_load(local_func_array_ptr_ptr, "local_func_array_ptr")
             .into_pointer_value();
+        tbaa_label(
+            module.clone(),
+            intrinsics,
+            "context_field_ptr_to_local_funcs",
+            local_func_array_ptr.as_instruction_value().unwrap(),
+            None,
+        );
         let local_func_ptr_ptr = unsafe {
             builder.build_in_bounds_gep(
                 local_func_array_ptr,
@@ -848,6 +930,13 @@ impl<'a> CtxType<'a> {
         let local_func_ptr = builder
             .build_load(local_func_ptr_ptr, "local_func_ptr")
             .into_pointer_value();
+        tbaa_label(
+            module.clone(),
+            intrinsics,
+            "local_func_ptr",
+            local_func_ptr.as_instruction_value().unwrap(),
+            Some(index.index() as u32),
+        );
         builder.build_pointer_cast(
             local_func_ptr,
             fn_ty.ptr_type(AddressSpace::Generic),
@@ -889,7 +978,12 @@ impl<'a> CtxType<'a> {
         })
     }
 
-    pub fn global_cache(&mut self, index: GlobalIndex, intrinsics: &Intrinsics) -> GlobalCache {
+    pub fn global_cache(
+        &mut self,
+        index: GlobalIndex,
+        intrinsics: &Intrinsics,
+        module: Rc<RefCell<Module>>,
+    ) -> GlobalCache {
         let (cached_globals, ctx_ptr_value, info, cache_builder) = (
             &mut self.cached_globals,
             self.ctx_ptr_value,
@@ -898,7 +992,7 @@ impl<'a> CtxType<'a> {
         );
 
         *cached_globals.entry(index).or_insert_with(|| {
-            let (globals_array_ptr_ptr, index, mutable, wasmer_ty) =
+            let (globals_array_ptr_ptr, index, mutable, wasmer_ty, field_name) =
                 match index.local_or_import(info) {
                     LocalOrImport::Local(local_global_index) => {
                         let desc = info.globals[local_global_index].desc;
@@ -913,6 +1007,7 @@ impl<'a> CtxType<'a> {
                             local_global_index.index() as u64,
                             desc.mutable,
                             desc.ty,
+                            "context_field_ptr_to_local_globals",
                         )
                     }
                     LocalOrImport::Import(import_global_index) => {
@@ -928,6 +1023,7 @@ impl<'a> CtxType<'a> {
                             import_global_index.index() as u64,
                             desc.mutable,
                             desc.ty,
+                            "context_field_ptr_to_imported_globals",
                         )
                     }
                 };
@@ -937,6 +1033,13 @@ impl<'a> CtxType<'a> {
             let global_array_ptr = cache_builder
                 .build_load(globals_array_ptr_ptr, "global_array_ptr")
                 .into_pointer_value();
+            tbaa_label(
+                module.clone(),
+                intrinsics,
+                field_name,
+                globals_array_ptr_ptr.as_instruction_value().unwrap(),
+                None,
+            );
             let const_index = intrinsics.i32_ty.const_int(index, false);
             let global_ptr_ptr = unsafe {
                 cache_builder.build_in_bounds_gep(
@@ -948,6 +1051,13 @@ impl<'a> CtxType<'a> {
             let global_ptr = cache_builder
                 .build_load(global_ptr_ptr, "global_ptr")
                 .into_pointer_value();
+            tbaa_label(
+                module.clone(),
+                intrinsics,
+                "global_ptr",
+                globals_array_ptr_ptr.as_instruction_value().unwrap(),
+                Some(index as u32),
+            );
 
             let global_ptr_typed =
                 cache_builder.build_pointer_cast(global_ptr, llvm_ptr_ty, "global_ptr_typed");
@@ -957,9 +1067,15 @@ impl<'a> CtxType<'a> {
                     ptr_to_value: global_ptr_typed,
                 }
             } else {
-                GlobalCache::Const {
+                let value = cache_builder.build_load(global_ptr_typed, "global_value");
-                    value: cache_builder.build_load(global_ptr_typed, "global_value"),
+                tbaa_label(
-                }
+                    module.clone(),
+                    intrinsics,
+                    "global",
+                    value.as_instruction_value().unwrap(),
+                    Some(index as u32),
+                );
+                GlobalCache::Const { value }
             }
         })
     }
@@ -968,6 +1084,7 @@ impl<'a> CtxType<'a> {
         &mut self,
         index: ImportedFuncIndex,
         intrinsics: &Intrinsics,
+        module: Rc<RefCell<Module>>,
     ) -> (PointerValue, PointerValue) {
         let (cached_imported_functions, ctx_ptr_value, cache_builder) = (
             &mut self.cached_imported_functions,
@@ -986,6 +1103,13 @@ impl<'a> CtxType<'a> {
             let func_array_ptr = cache_builder
                 .build_load(func_array_ptr_ptr, "func_array_ptr")
                 .into_pointer_value();
+            tbaa_label(
+                module.clone(),
+                intrinsics,
+                "context_field_ptr_to_imported_funcs",
+                func_array_ptr.as_instruction_value().unwrap(),
+                None,
+            );
             let const_index = intrinsics.i32_ty.const_int(index.index() as u64, false);
             let imported_func_ptr = unsafe {
                 cache_builder.build_in_bounds_gep(
@@ -1007,6 +1131,20 @@ impl<'a> CtxType<'a> {
             let ctx_ptr = cache_builder
                 .build_load(ctx_ptr_ptr, "ctx_ptr")
                 .into_pointer_value();
+            tbaa_label(
+                module.clone(),
+                intrinsics,
+                "imported_func_ptr",
+                func_ptr.as_instruction_value().unwrap(),
+                Some(index.index() as u32),
+            );
+            tbaa_label(
+                module.clone(),
+                intrinsics,
+                "imported_func_ctx_ptr",
+                ctx_ptr.as_instruction_value().unwrap(),
+                Some(index.index() as u32),
+            );
 
             ImportedFuncCache { func_ptr, ctx_ptr }
         });
@@ -1018,6 +1156,7 @@ impl<'a> CtxType<'a> {
         &mut self,
         index: usize,
         intrinsics: &Intrinsics,
+        module: Rc<RefCell<Module>>,
         builder: &Builder,
     ) -> PointerValue {
         assert!(index < INTERNALS_SIZE);
@@ -1032,6 +1171,13 @@ impl<'a> CtxType<'a> {
         let local_internals_ptr = builder
             .build_load(local_internals_ptr_ptr, "local_internals_ptr")
             .into_pointer_value();
+        tbaa_label(
+            module.clone(),
+            intrinsics,
+            "context_field_ptr_to_internals",
+            local_internals_ptr_ptr.as_instruction_value().unwrap(),
+            None,
+        );
         unsafe {
             builder.build_in_bounds_gep(
                 local_internals_ptr,
@@ -1041,3 +1187,83 @@ impl<'a> CtxType<'a> {
         }
     }
 }
+
+// Given an instruction that operates on memory, mark the access as not aliasing
+// other memory accesses which have a different (label, index) pair.
+pub fn tbaa_label(
+    module: Rc<RefCell<Module>>,
+    intrinsics: &Intrinsics,
+    label: &str,
+    instruction: InstructionValue,
+    index: Option<u32>,
+) {
+    // To convey to LLVM that two pointers must be pointing to distinct memory,
+    // we use LLVM's Type Based Aliasing Analysis, or TBAA, to mark the memory
+    // operations as having different types whose pointers may not alias.
+    //
+    // See the LLVM documentation at
+    //   https://llvm.org/docs/LangRef.html#tbaa-metadata
+    //
+    // LLVM TBAA supports many features, but we use it in a simple way, with
+    // only scalar types that are children of the root node. Every TBAA type we
+    // declare is NoAlias with the others. See NoAlias, PartialAlias,
+    // MayAlias and MustAlias in the LLVM documentation:
+    //   https://llvm.org/docs/AliasAnalysis.html#must-may-and-no-alias-responses
+
+    let module = module.borrow_mut();
+    let context = module.get_context();
+
+    // `!wasmer_tbaa_root = {}`, the TBAA root node for wasmer.
+    let tbaa_root = module
+        .get_global_metadata("wasmer_tbaa_root")
+        .pop()
+        .unwrap_or_else(|| {
+            module.add_global_metadata("wasmer_tbaa_root", &MetadataValue::create_node(&[]));
+            module.get_global_metadata("wasmer_tbaa_root")[0]
+        });
+
+    // Construct (or look up) the type descriptor, for example
+    //   `!"local 0" = !{!"local 0", !wasmer_tbaa_root}`.
+    let label = if let Some(idx) = index {
+        format!("{}{}", label, idx)
+    } else {
+        label.to_string()
+    };
+    let type_label = context.metadata_string(label.as_str());
+    let type_tbaa = module
+        .get_global_metadata(label.as_str())
+        .pop()
+        .unwrap_or_else(|| {
+            module.add_global_metadata(
+                label.as_str(),
+                &MetadataValue::create_node(&[type_label.into(), tbaa_root.into()]),
+            );
+            module.get_global_metadata(label.as_str())[0]
+        });
+
+    // Construct (or look up) the access tag, which is a struct of the form
+    // (base type, access type, offset).
+    //
+    // "If BaseTy is a scalar type, Offset must be 0 and BaseTy and AccessTy
+    // must be the same".
+    //   -- https://llvm.org/docs/LangRef.html#tbaa-metadata
+    let label = label + "_memop";
+    let type_tbaa = module
+        .get_global_metadata(label.as_str())
+        .pop()
+        .unwrap_or_else(|| {
+            module.add_global_metadata(
+                label.as_str(),
+                &MetadataValue::create_node(&[
+                    type_tbaa.into(),
+                    type_tbaa.into(),
+                    intrinsics.i64_zero.into(),
+                ]),
+            );
+            module.get_global_metadata(label.as_str())[0]
+        });
+
+    // Attach the access tag to the instruction.
+    let tbaa_kind = context.get_kind_id("tbaa");
+    instruction.set_metadata(type_tbaa, tbaa_kind);
+}