Chaos mode MVP: Skip branch optimization in MachBuffer (#6039)

* fuzz: Add chaos mode control plane

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* fuzz: Skip branch optimization with chaos mode

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* fuzz: Rename chaos engine -> control plane

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* chaos mode: refactoring ControlPlane to be passed through the call stack by reference

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Remo Senekowitsch <contact@remsle.dev>

* fuzz: annotate chaos todos

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* fuzz: cleanup control plane

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* fuzz: remove control plane from compiler context

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* fuzz: move control plane into emit state

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* fuzz: fix remaining compiler errors

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* fix tests

* refactor emission state ctrl plane accessors

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* centralize conditional compilation of chaos mode

Also cleanup a few straggling dependencies on cranelift-control
that aren't needed anymore.

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* add cranelift-control to published crates

prtest:full

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

* add cranelift-control to public crates

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>

---------

Co-authored-by: Falk Zwimpfer <24669719+FalkZ@users.noreply.github.com>
Co-authored-by: Moritz Waser <mzrw.dev@pm.me>
Co-authored-by: Remo Senekowitsch <contact@remsle.dev>

crates/cranelift-shared/Cargo.toml

@@ -12,6 +12,7 @@ edition.workspace = true
 anyhow = { workspace = true }
 wasmtime-environ = { workspace = true }
 cranelift-codegen = { workspace = true }
+cranelift-control = { workspace = true }
 cranelift-native = { workspace = true }
 target-lexicon = { workspace = true }
 gimli = { workspace = true }

crates/cranelift-shared/src/obj.rs

@@ -19,6 +19,7 @@ use cranelift_codegen::binemit::Reloc;
 use cranelift_codegen::ir::LibCall;
 use cranelift_codegen::isa::unwind::{systemv, UnwindInfo};
 use cranelift_codegen::TextSectionBuilder;
+use cranelift_control::ControlPlane;
 use gimli::write::{Address, EhFrame, EndianVec, FrameTable, Writer};
 use gimli::RunTimeEndian;
 use object::write::{Object, SectionId, StandardSegment, Symbol, SymbolId, SymbolSection};
@@ -59,6 +60,8 @@ pub struct ModuleTextBuilder<'a> {
     /// Note that this isn't typically used. It's only used for SSE-disabled
     /// builds without SIMD on x86_64 right now.
     libcall_symbols: HashMap<LibCall, SymbolId>,
+
+    ctrl_plane: ControlPlane,
 }
 
 impl<'a> ModuleTextBuilder<'a> {
@@ -88,6 +91,7 @@ impl<'a> ModuleTextBuilder<'a> {
             unwind_info: Default::default(),
             text,
             libcall_symbols: HashMap::default(),
+            ctrl_plane: ControlPlane::default(),
         }
     }
 
@@ -115,6 +119,7 @@ impl<'a> ModuleTextBuilder<'a> {
             true,
             &body,
             self.compiler.function_alignment().max(alignment),
+            &mut self.ctrl_plane,
         );
 
         let symbol_id = self.obj.add_symbol(Symbol {
@@ -227,7 +232,8 @@ impl<'a> ModuleTextBuilder<'a> {
         if padding == 0 {
             return;
         }
-        self.text.append(false, &vec![0; padding], 1);
+        self.text
+            .append(false, &vec![0; padding], 1, &mut self.ctrl_plane);
     }
 
     /// Indicates that the text section has been written completely and this
@@ -237,7 +243,7 @@ impl<'a> ModuleTextBuilder<'a> {
     /// necessary.
     pub fn finish(mut self) {
         // Finish up the text section now that we're done adding functions.
-        let text = self.text.finish();
+        let text = self.text.finish(&mut self.ctrl_plane);
         self.obj
             .section_mut(self.text_section)
             .set_data(text, self.compiler.page_size_align());

crates/cranelift/Cargo.toml

@@ -19,6 +19,7 @@ cranelift-codegen = { workspace = true }
 cranelift-frontend = { workspace = true }
 cranelift-entity = { workspace = true }
 cranelift-native = { workspace = true }
+cranelift-control = { workspace = true }
 wasmtime-cranelift-shared = { workspace = true }
 wasmparser = { workspace = true }
 target-lexicon = { workspace = true }

crates/cranelift/src/compiler.rs

@@ -612,7 +612,7 @@ fn compile_uncached<'a>(
 ) -> Result<(&'a CompiledCode, Vec<u8>), CompileError> {
     let mut code_buf = Vec::new();
     let compiled_code = context
-        .compile_and_emit(isa, &mut code_buf)
+        .compile_and_emit(isa, &mut code_buf, &mut Default::default())
         .map_err(|error| CompileError::Codegen(pretty_error(&error.func, error.inner)))?;
     Ok((compiled_code, code_buf))
 }