Auto merge of #125025 - saethlin:clone-your-body, r=<try>

[perf experiments] Clone all MIR bodies

We keep saying things like cloning all the MIR would be expensive, but... how expensive actually?

Author: bors

Cargo.lock

@@ -3826,6 +3826,7 @@ dependencies = [
  "rustc_macros",
  "rustc_metadata",
  "rustc_middle",
+ "rustc_mir_transform",
  "rustc_monomorphize",
  "rustc_query_system",
  "rustc_serialize",

compiler/rustc_codegen_cranelift/src/base.rs

@@ -5,6 +5,7 @@ use cranelift_codegen::CodegenError;
 use cranelift_frontend::{FunctionBuilder, FunctionBuilderContext};
 use cranelift_module::ModuleError;
 use rustc_ast::InlineAsmOptions;
+use rustc_codegen_ssa::mir::make_codegen_mir;
 use rustc_index::IndexVec;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::ty::adjustment::PointerCoercion;
@@ -40,7 +41,8 @@ pub(crate) fn codegen_fn<'tcx>(
     let symbol_name = tcx.symbol_name(instance).name.to_string();
     let _timer = tcx.prof.generic_activity_with_arg("codegen fn", &*symbol_name);
 
-    let mir = tcx.instance_mir(instance.def);
+    let mir = make_codegen_mir(tcx, instance);
+    let mir = &mir;
     let _mir_guard = crate::PrintOnPanic(|| {
         let mut buf = Vec::new();
         with_no_trimmed_paths!({
@@ -302,19 +304,10 @@ fn codegen_fn_body(fx: &mut FunctionCx<'_, '_, '_>, start_block: Block) {
         .generic_activity("codegen prelude")
         .run(|| crate::abi::codegen_fn_prelude(fx, start_block));
 
-    let reachable_blocks = traversal::mono_reachable_as_bitset(fx.mir, fx.tcx, fx.instance);
-
     for (bb, bb_data) in fx.mir.basic_blocks.iter_enumerated() {
         let block = fx.get_block(bb);
         fx.bcx.switch_to_block(block);
 
-        if !reachable_blocks.contains(bb) {
-            // We want to skip this block, because it's not reachable. But we still create
-            // the block so terminators in other blocks can reference it.
-            fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
-            continue;
-        }
-
         if bb_data.is_cleanup {
             // Unwinding after panicking is not supported
             continue;

compiler/rustc_codegen_cranelift/src/common.rs

@@ -283,7 +283,7 @@ pub(crate) fn create_wrapper_function(
     unwind_context.add_function(wrapper_func_id, &ctx, module.isa());
 }
 
-pub(crate) struct FunctionCx<'m, 'clif, 'tcx: 'm> {
+pub(crate) struct FunctionCx<'m, 'clif, 'tcx> {
     pub(crate) cx: &'clif mut crate::CodegenCx,
     pub(crate) module: &'m mut dyn Module,
     pub(crate) tcx: TyCtxt<'tcx>,
@@ -294,7 +294,7 @@ pub(crate) struct FunctionCx<'m, 'clif, 'tcx: 'm> {
 
     pub(crate) instance: Instance<'tcx>,
     pub(crate) symbol_name: String,
-    pub(crate) mir: &'tcx Body<'tcx>,
+    pub(crate) mir: &'m Body<'tcx>,
     pub(crate) fn_abi: &'tcx FnAbi<'tcx, Ty<'tcx>>,
 
     pub(crate) bcx: FunctionBuilder<'clif>,

compiler/rustc_codegen_ssa/Cargo.toml

@@ -27,6 +27,7 @@ rustc_index = { path = "../rustc_index" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_metadata = { path = "../rustc_metadata" }
 rustc_middle = { path = "../rustc_middle" }
+rustc_mir_transform = { path = "../rustc_mir_transform" }
 rustc_monomorphize = { path = "../rustc_monomorphize" }
 rustc_query_system = { path = "../rustc_query_system" }
 rustc_serialize = { path = "../rustc_serialize" }

compiler/rustc_codegen_ssa/src/mir/analyze.rs

@@ -13,8 +13,8 @@ use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
 use rustc_middle::{bug, span_bug};
 use tracing::debug;
 
-pub fn non_ssa_locals<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
-    fx: &FunctionCx<'a, 'tcx, Bx>,
+pub fn non_ssa_locals<'body, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
+    fx: &FunctionCx<'body, 'a, 'tcx, Bx>,
 ) -> BitSet<mir::Local> {
     let mir = fx.mir;
     let dominators = mir.basic_blocks.dominators();
@@ -69,9 +69,9 @@ enum LocalKind {
     SSA(DefLocation),
 }
 
-struct LocalAnalyzer<'mir, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
-    fx: &'mir FunctionCx<'a, 'tcx, Bx>,
-    dominators: &'mir Dominators<mir::BasicBlock>,
+struct LocalAnalyzer<'body, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
+    fx: &'body FunctionCx<'body, 'a, 'tcx, Bx>,
+    dominators: &'body Dominators<mir::BasicBlock>,
     locals: IndexVec<mir::Local, LocalKind>,
 }
 

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -39,17 +39,17 @@ enum MergingSucc {
 
 /// Used by `FunctionCx::codegen_terminator` for emitting common patterns
 /// e.g., creating a basic block, calling a function, etc.
-struct TerminatorCodegenHelper<'tcx> {
+struct TerminatorCodegenHelper<'body, 'tcx> {
     bb: mir::BasicBlock,
-    terminator: &'tcx mir::Terminator<'tcx>,
+    terminator: &'body mir::Terminator<'tcx>,
 }
 
-impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
+impl<'body, 'a, 'tcx> TerminatorCodegenHelper<'body, 'tcx> {
     /// Returns the appropriate `Funclet` for the current funclet, if on MSVC,
     /// either already previously cached, or newly created, by `landing_pad_for`.
     fn funclet<'b, Bx: BuilderMethods<'a, 'tcx>>(
         &self,
-        fx: &'b mut FunctionCx<'a, 'tcx, Bx>,
+        fx: &'b mut FunctionCx<'body, 'a, 'tcx, Bx>,
     ) -> Option<&'b Bx::Funclet> {
         let cleanup_kinds = fx.cleanup_kinds.as_ref()?;
         let funclet_bb = cleanup_kinds[self.bb].funclet_bb(self.bb)?;
@@ -75,7 +75,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
     /// stuff in it or next to it.
     fn llbb_with_cleanup<Bx: BuilderMethods<'a, 'tcx>>(
         &self,
-        fx: &mut FunctionCx<'a, 'tcx, Bx>,
+        fx: &mut FunctionCx<'body, 'a, 'tcx, Bx>,
         target: mir::BasicBlock,
     ) -> Bx::BasicBlock {
         let (needs_landing_pad, is_cleanupret) = self.llbb_characteristics(fx, target);
@@ -99,7 +99,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
 
     fn llbb_characteristics<Bx: BuilderMethods<'a, 'tcx>>(
         &self,
-        fx: &mut FunctionCx<'a, 'tcx, Bx>,
+        fx: &mut FunctionCx<'body, 'a, 'tcx, Bx>,
         target: mir::BasicBlock,
     ) -> (bool, bool) {
         if let Some(ref cleanup_kinds) = fx.cleanup_kinds {
@@ -124,7 +124,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
 
     fn funclet_br<Bx: BuilderMethods<'a, 'tcx>>(
         &self,
-        fx: &mut FunctionCx<'a, 'tcx, Bx>,
+        fx: &mut FunctionCx<'body, 'a, 'tcx, Bx>,
         bx: &mut Bx,
         target: mir::BasicBlock,
         mergeable_succ: bool,
@@ -153,7 +153,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
     /// return destination `destination` and the unwind action `unwind`.
     fn do_call<Bx: BuilderMethods<'a, 'tcx>>(
         &self,
-        fx: &mut FunctionCx<'a, 'tcx, Bx>,
+        fx: &mut FunctionCx<'body, 'a, 'tcx, Bx>,
         bx: &mut Bx,
         fn_abi: &'tcx FnAbi<'tcx, Ty<'tcx>>,
         fn_ptr: Bx::Value,
@@ -272,7 +272,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
     /// Generates inline assembly with optional `destination` and `unwind`.
     fn do_inlineasm<Bx: BuilderMethods<'a, 'tcx>>(
         &self,
-        fx: &mut FunctionCx<'a, 'tcx, Bx>,
+        fx: &mut FunctionCx<'body, 'a, 'tcx, Bx>,
         bx: &mut Bx,
         template: &[InlineAsmTemplatePiece],
         operands: &[InlineAsmOperandRef<'tcx, Bx>],
@@ -339,9 +339,13 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
 }
 
 /// Codegen implementations for some terminator variants.
-impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
+impl<'body, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'body, 'a, 'tcx, Bx> {
     /// Generates code for a `Resume` terminator.
-    fn codegen_resume_terminator(&mut self, helper: TerminatorCodegenHelper<'tcx>, bx: &mut Bx) {
+    fn codegen_resume_terminator(
+        &mut self,
+        helper: TerminatorCodegenHelper<'body, 'tcx>,
+        bx: &mut Bx,
+    ) {
         if let Some(funclet) = helper.funclet(self) {
             bx.cleanup_ret(funclet, None);
         } else {
@@ -358,7 +362,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
     fn codegen_switchint_terminator(
         &mut self,
-        helper: TerminatorCodegenHelper<'tcx>,
+        helper: TerminatorCodegenHelper<'body, 'tcx>,
         bx: &mut Bx,
         discr: &mir::Operand<'tcx>,
         targets: &SwitchTargets,
@@ -498,7 +502,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     #[tracing::instrument(level = "trace", skip(self, helper, bx))]
     fn codegen_drop_terminator(
         &mut self,
-        helper: TerminatorCodegenHelper<'tcx>,
+        helper: TerminatorCodegenHelper<'body, 'tcx>,
         bx: &mut Bx,
         source_info: &mir::SourceInfo,
         location: mir::Place<'tcx>,
@@ -640,7 +644,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
     fn codegen_assert_terminator(
         &mut self,
-        helper: TerminatorCodegenHelper<'tcx>,
+        helper: TerminatorCodegenHelper<'body, 'tcx>,
         bx: &mut Bx,
         terminator: &mir::Terminator<'tcx>,
         cond: &mir::Operand<'tcx>,
@@ -719,7 +723,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
     fn codegen_terminate_terminator(
         &mut self,
-        helper: TerminatorCodegenHelper<'tcx>,
+        helper: TerminatorCodegenHelper<'body, 'tcx>,
         bx: &mut Bx,
         terminator: &mir::Terminator<'tcx>,
         reason: UnwindTerminateReason,
@@ -749,7 +753,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     /// Returns `Some` if this is indeed a panic intrinsic and codegen is done.
     fn codegen_panic_intrinsic(
         &mut self,
-        helper: &TerminatorCodegenHelper<'tcx>,
+        helper: &TerminatorCodegenHelper<'body, 'tcx>,
         bx: &mut Bx,
         intrinsic: Option<ty::IntrinsicDef>,
         instance: Option<Instance<'tcx>>,
@@ -818,7 +822,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
     fn codegen_call_terminator(
         &mut self,
-        helper: TerminatorCodegenHelper<'tcx>,
+        helper: TerminatorCodegenHelper<'body, 'tcx>,
         bx: &mut Bx,
         terminator: &mir::Terminator<'tcx>,
         func: &mir::Operand<'tcx>,
@@ -1170,7 +1174,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
     fn codegen_asm_terminator(
         &mut self,
-        helper: TerminatorCodegenHelper<'tcx>,
+        helper: TerminatorCodegenHelper<'body, 'tcx>,
         bx: &mut Bx,
         terminator: &mir::Terminator<'tcx>,
         template: &[ast::InlineAsmTemplatePiece],
@@ -1254,7 +1258,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     }
 }
 
-impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
+impl<'body, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'body, 'a, 'tcx, Bx> {
     pub fn codegen_block(&mut self, mut bb: mir::BasicBlock) {
         let llbb = match self.try_llbb(bb) {
             Some(llbb) => llbb,
@@ -1309,7 +1313,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         &mut self,
         bx: &mut Bx,
         bb: mir::BasicBlock,
-        terminator: &'tcx mir::Terminator<'tcx>,
+        terminator: &'body mir::Terminator<'tcx>,
     ) -> MergingSucc {
         debug!("codegen_terminator: {:?}", terminator);
 

compiler/rustc_codegen_ssa/src/mir/constant.rs

@@ -10,7 +10,7 @@ use rustc_target::abi::Abi;
 
 use super::FunctionCx;
 
-impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
+impl<'body, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'body, 'a, 'tcx, Bx> {
     pub fn eval_mir_constant_to_operand(
         &self,
         bx: &mut Bx,

compiler/rustc_codegen_ssa/src/mir/coverageinfo.rs

@@ -5,7 +5,7 @@ use rustc_middle::mir::SourceScope;
 
 use super::FunctionCx;
 
-impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
+impl<'body, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'body, 'a, 'tcx, Bx> {
     pub fn codegen_coverage(&self, bx: &mut Bx, kind: &CoverageKind, scope: SourceScope) {
         // Determine the instance that coverage data was originally generated for.
         let instance = if let Some(inlined) = scope.inlined_instance(&self.mir.source_scopes) {

compiler/rustc_codegen_ssa/src/mir/debuginfo.rs

@@ -203,7 +203,7 @@ fn calculate_debuginfo_offset<
     DebugInfoOffset { direct_offset, indirect_offsets, result: place }
 }
 
-impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
+impl<'body, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'body, 'a, 'tcx, Bx> {
     pub fn set_debug_loc(&self, bx: &mut Bx, source_info: mir::SourceInfo) {
         bx.set_span(source_info.span);
         if let Some(dbg_loc) = self.dbg_loc(source_info) {

compiler/rustc_codegen_ssa/src/mir/intrinsic.rs

@@ -54,7 +54,7 @@ fn memset_intrinsic<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     bx.memset(dst, val, size, align, flags);
 }
 
-impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
+impl<'body, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'body, 'a, 'tcx, Bx> {
     /// In the `Err` case, returns the instance that should be called instead.
     pub fn codegen_intrinsic_call(
         bx: &mut Bx,