Rollup merge of #61297 - eddyb:forsaken-stats, r=nagisa

Remove LLVM instruction stats and other (obsolete) codegen stats.

Both `-Z count_llvm_insns` and `-Z codegen-stats` are removed, as (AFAIK) they have been of little use in the last few years, especially after the transition to MIR->LLVM codegen.

Other than for the LLVM instruction counts, `-Z codegen-stats` has long been obsoleted anyway.

r? @nagisa cc @rust-lang/compiler

src/librustc/mir/mono.rs

@@ -188,49 +188,6 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for CodegenUnit<'tcx> {
     }
 }
 
-#[derive(Clone, Default)]
-pub struct Stats {
-    pub n_glues_created: usize,
-    pub n_null_glues: usize,
-    pub n_real_glues: usize,
-    pub n_fns: usize,
-    pub n_inlines: usize,
-    pub n_closures: usize,
-    pub n_llvm_insns: usize,
-    pub llvm_insns: FxHashMap<String, usize>,
-    // (ident, llvm-instructions)
-    pub fn_stats: Vec<(String, usize)>,
-}
-
-impl_stable_hash_for!(struct self::Stats {
-    n_glues_created,
-    n_null_glues,
-    n_real_glues,
-    n_fns,
-    n_inlines,
-    n_closures,
-    n_llvm_insns,
-    llvm_insns,
-    fn_stats
-});
-
-impl Stats {
-    pub fn extend(&mut self, stats: Stats) {
-        self.n_glues_created += stats.n_glues_created;
-        self.n_null_glues += stats.n_null_glues;
-        self.n_real_glues += stats.n_real_glues;
-        self.n_fns += stats.n_fns;
-        self.n_inlines += stats.n_inlines;
-        self.n_closures += stats.n_closures;
-        self.n_llvm_insns += stats.n_llvm_insns;
-
-        for (k, v) in stats.llvm_insns {
-            *self.llvm_insns.entry(k).or_insert(0) += v;
-        }
-        self.fn_stats.extend(stats.fn_stats);
-    }
-}
-
 pub struct CodegenUnitNameBuilder<'a, 'gcx: 'tcx, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'gcx, 'tcx>,
     cache: FxHashMap<CrateNum, String>,

src/librustc/session/config.rs

@@ -1216,21 +1216,12 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "measure time of each rustc pass"),
     time: bool = (false, parse_bool, [UNTRACKED],
         "measure time of rustc processes"),
-    count_llvm_insns: bool = (false, parse_bool,
-        [UNTRACKED_WITH_WARNING(true,
-        "The output generated by `-Z count_llvm_insns` might not be reliable \
-         when used with incremental compilation")],
-        "count where LLVM instrs originate"),
     time_llvm_passes: bool = (false, parse_bool, [UNTRACKED_WITH_WARNING(true,
         "The output of `-Z time-llvm-passes` will only reflect timings of \
          re-codegened modules when used with incremental compilation" )],
         "measure time of each LLVM pass"),
     input_stats: bool = (false, parse_bool, [UNTRACKED],
         "gather statistics about the input"),
-    codegen_stats: bool = (false, parse_bool, [UNTRACKED_WITH_WARNING(true,
-        "The output of `-Z codegen-stats` might not be accurate when incremental \
-         compilation is enabled")],
-        "gather codegen statistics"),
     asm_comments: bool = (false, parse_bool, [TRACKED],
         "generate comments into the assembly (may change behavior)"),
     verify_llvm_ir: bool = (false, parse_bool, [TRACKED],
@@ -3259,14 +3250,10 @@ mod tests {
         assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
         opts.debugging_opts.time_passes = true;
         assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
-        opts.debugging_opts.count_llvm_insns = true;
-        assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
         opts.debugging_opts.time_llvm_passes = true;
         assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
         opts.debugging_opts.input_stats = true;
         assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
-        opts.debugging_opts.codegen_stats = true;
-        assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
         opts.debugging_opts.borrowck_stats = true;
         assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
         opts.debugging_opts.meta_stats = true;

src/librustc/session/mod.rs

@@ -519,15 +519,9 @@ impl Session {
     pub fn instrument_mcount(&self) -> bool {
         self.opts.debugging_opts.instrument_mcount
     }
-    pub fn count_llvm_insns(&self) -> bool {
-        self.opts.debugging_opts.count_llvm_insns
-    }
     pub fn time_llvm_passes(&self) -> bool {
         self.opts.debugging_opts.time_llvm_passes
     }
-    pub fn codegen_stats(&self) -> bool {
-        self.opts.debugging_opts.codegen_stats
-    }
     pub fn meta_stats(&self) -> bool {
         self.opts.debugging_opts.meta_stats
     }

src/librustc_codegen_llvm/base.rs

@@ -24,7 +24,7 @@ use crate::common;
 use crate::context::CodegenCx;
 use crate::monomorphize::partitioning::CodegenUnitExt;
 use rustc::dep_graph;
-use rustc::mir::mono::{Linkage, Visibility, Stats};
+use rustc::mir::mono::{Linkage, Visibility};
 use rustc::middle::cstore::{EncodedMetadata};
 use rustc::ty::TyCtxt;
 use rustc::middle::exported_symbols;
@@ -104,17 +104,17 @@ pub fn iter_globals(llmod: &'ll llvm::Module) -> ValueIter<'ll> {
     }
 }
 
-pub fn compile_codegen_unit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                                  cgu_name: InternedString)
-                                  -> Stats {
+pub fn compile_codegen_unit(tcx: TyCtxt<'a, 'tcx, 'tcx>, cgu_name: InternedString) {
     let start_time = Instant::now();
 
     let dep_node = tcx.codegen_unit(cgu_name).codegen_dep_node(tcx);
-    let ((stats, module), _) = tcx.dep_graph.with_task(dep_node,
-                                                       tcx,
-                                                       cgu_name,
-                                                       module_codegen,
-                                                       dep_graph::hash_result);
+    let (module, _) = tcx.dep_graph.with_task(
+        dep_node,
+        tcx,
+        cgu_name,
+        module_codegen,
+        dep_graph::hash_result,
+    );
     let time_to_codegen = start_time.elapsed();
 
     // We assume that the cost to run LLVM on a CGU is proportional to
@@ -123,17 +123,15 @@ pub fn compile_codegen_unit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                time_to_codegen.subsec_nanos() as u64;
 
     submit_codegened_module_to_llvm(&LlvmCodegenBackend(()), tcx, module, cost);
-    return stats;
 
     fn module_codegen<'ll, 'tcx>(
         tcx: TyCtxt<'ll, 'tcx, 'tcx>,
-        cgu_name: InternedString)
-        -> (Stats, ModuleCodegen<ModuleLlvm>)
-    {
+        cgu_name: InternedString,
+    ) -> ModuleCodegen<ModuleLlvm> {
         let cgu = tcx.codegen_unit(cgu_name);
         // Instantiate monomorphizations without filling out definitions yet...
         let llvm_module = ModuleLlvm::new(tcx, &cgu_name.as_str());
-        let stats = {
+        {
             let cx = CodegenCx::new(tcx, cgu, &llvm_module);
             let mono_items = cx.codegen_unit
                                .items_in_deterministic_order(cx.tcx);
@@ -169,15 +167,13 @@ pub fn compile_codegen_unit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             if cx.sess().opts.debuginfo != DebugInfo::None {
                 cx.debuginfo_finalize();
             }
+        }
 
-            cx.consume_stats().into_inner()
-        };
-
-        (stats, ModuleCodegen {
+        ModuleCodegen {
             name: cgu_name.to_string(),
             module_llvm: llvm_module,
             kind: ModuleKind::Regular,
-        })
+        }
     }
 }