Remove heaps from core Cranelift, push them into cranelift-wasm (#5386)

* cranelift-wasm: translate Wasm loads into lower-level CLIF operations

Rather than using `heap_{load,store,addr}`.

* cranelift: Remove the `heap_{addr,load,store}` instructions

These are now legalized in the `cranelift-wasm` frontend.

* cranelift: Remove the `ir::Heap` entity from CLIF

* Port basic memory operation tests to .wat filetests

* Remove test for verifying CLIF heaps

* Remove `heap_addr` from replace_branching_instructions_and_cfg_predecessors.clif test

* Remove `heap_addr` from readonly.clif test

* Remove `heap_addr` from `table_addr.clif` test

* Remove `heap_addr` from the simd-fvpromote_low.clif test

* Remove `heap_addr` from simd-fvdemote.clif test

* Remove `heap_addr` from the load-op-store.clif test

* Remove the CLIF heap runtest

* Remove `heap_addr` from the global_value.clif test

* Remove `heap_addr` from fpromote.clif runtests

* Remove `heap_addr` from fdemote.clif runtests

* Remove `heap_addr` from memory.clif parser test

* Remove `heap_addr` from reject_load_readonly.clif test

* Remove `heap_addr` from reject_load_notrap.clif test

* Remove `heap_addr` from load_readonly_notrap.clif test

* Remove `static-heap-without-guard-pages.clif` test

Will be subsumed when we port `make-heap-load-store-tests.sh` to generating
`.wat` tests.

* Remove `static-heap-with-guard-pages.clif` test

Will be subsumed when we port `make-heap-load-store-tests.sh` over to `.wat`
tests.

* Remove more heap tests

These will be subsumed by porting `make-heap-load-store-tests.sh` over to `.wat`
tests.

* Remove `heap_addr` from `simple-alias.clif` test

* Remove `heap_addr` from partial-redundancy.clif test

* Remove `heap_addr` from multiple-blocks.clif test

* Remove `heap_addr` from fence.clif test

* Remove `heap_addr` from extends.clif test

* Remove runtests that rely on heaps

Heaps are not a thing in CLIF or the interpreter anymore

* Add generated load/store `.wat` tests

* Enable memory-related wasm features in `.wat` tests

* Remove CLIF heap from fcmp-mem-bug.clif test

* Add a mode for compiling `.wat` all the way to assembly in filetests

* Also generate WAT to assembly tests in `make-load-store-tests.sh`

* cargo fmt

* Reinstate `f{de,pro}mote.clif` tests without the heap bits

* Remove undefined doc link

* Remove outdated SVG and dot file from docs

* Add docs about `None` returns for base address computation helpers

* Factor out `env.heap_access_spectre_mitigation()` to a local

* Expand docs for `FuncEnvironment::heaps` trait method

* Restore f{de,pro}mote+load clif runtests with stack memory

cranelift/wasm/src/state.rs

@@ -4,7 +4,7 @@
 //! value and control stacks during the translation of a single function.
 
 use crate::environ::{FuncEnvironment, GlobalVariable};
-use crate::{FuncIndex, GlobalIndex, MemoryIndex, TableIndex, TypeIndex, WasmResult};
+use crate::{FuncIndex, GlobalIndex, Heap, MemoryIndex, TableIndex, TypeIndex, WasmResult};
 use crate::{HashMap, Occupied, Vacant};
 use cranelift_codegen::ir::{self, Block, Inst, Value};
 use std::vec::Vec;
@@ -225,7 +225,7 @@ pub struct FuncTranslationState {
     globals: HashMap<GlobalIndex, GlobalVariable>,
 
     // Map of heaps that have been created by `FuncEnvironment::make_heap`.
-    heaps: HashMap<MemoryIndex, ir::Heap>,
+    memory_to_heap: HashMap<MemoryIndex, Heap>,
 
     // Map of tables that have been created by `FuncEnvironment::make_table`.
     pub(crate) tables: HashMap<TableIndex, ir::Table>,
@@ -258,7 +258,7 @@ impl FuncTranslationState {
             control_stack: Vec::new(),
             reachable: true,
             globals: HashMap::new(),
-            heaps: HashMap::new(),
+            memory_to_heap: HashMap::new(),
             tables: HashMap::new(),
             signatures: HashMap::new(),
             functions: HashMap::new(),
@@ -270,7 +270,7 @@ impl FuncTranslationState {
         debug_assert!(self.control_stack.is_empty());
         self.reachable = true;
         self.globals.clear();
-        self.heaps.clear();
+        self.memory_to_heap.clear();
         self.tables.clear();
         self.signatures.clear();
         self.functions.clear();
@@ -462,9 +462,9 @@ impl FuncTranslationState {
         func: &mut ir::Function,
         index: u32,
         environ: &mut FE,
-    ) -> WasmResult<ir::Heap> {
+    ) -> WasmResult<Heap> {
         let index = MemoryIndex::from_u32(index);
-        match self.heaps.entry(index) {
+        match self.memory_to_heap.entry(index) {
             Occupied(entry) => Ok(*entry.get()),
             Vacant(entry) => Ok(*entry.insert(environ.make_heap(func, index)?)),
         }