Auto merge of rust-lang#156535 - JonathanBrouwer:rollup-9oxBSQK, r=JonathanBrouwer

Rollup of 5 pull requests

Successful merges:

 - rust-lang#156472 (Add support for Zprint-codegen-stats-json)
 - rust-lang#156504 (bootstrap: remap windows-style OUT_DIR paths)
 - rust-lang#156513 (miri subtree update)
 - rust-lang#156524 (Remove the dummy `PreCodegen` mir-opt pass, and use `runtime-optimized` instead)
 - rust-lang#156325 (Don't treat const param default as projection)

Author: bors

Cargo.lock

@@ -373,6 +373,10 @@ impl CodegenBackend for LlvmCodegenBackend {
         print!("{stats}");
     }
 
+    fn print_statistics_json(&self) -> String {
+        llvm::build_string(|s| unsafe { llvm::LLVMRustPrintStatisticsJSON(s) }).unwrap()
+    }
+
     fn link(
         &self,
         sess: &Session,

compiler/rustc_codegen_llvm/src/lib.rs

@@ -2114,6 +2114,9 @@ unsafe extern "C" {
     /// Prints the statistics collected by `-Zprint-codegen-stats`.
     pub(crate) fn LLVMRustPrintStatistics(OutStr: &RustString);
 
+    /// Save the statistics collected by `-Zprint-codegen-stats-json`
+    pub(crate) fn LLVMRustPrintStatisticsJSON(OutStr: &RustString);
+
     pub(crate) fn LLVMRustInlineAsmVerify(
         Ty: &Type,
         Constraints: *const c_uchar, // See "PTR_LEN_STR".

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -120,7 +120,7 @@ unsafe fn configure_llvm(sess: &Session) {
         // Use non-zero `import-instr-limit` multiplier for cold callsites.
         add("-import-cold-multiplier=0.1", false);
 
-        if sess.print_llvm_stats() {
+        if sess.print_llvm_stats() || sess.print_llvm_stats_json().is_some() {
             add("-stats", false);
         }
 

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -131,6 +131,10 @@ pub trait CodegenBackend {
 
     fn print_statistics(&self) {}
 
+    fn print_statistics_json(&self) -> String {
+        String::new()
+    }
+
     /// This is called on the returned [`CompiledModules`] from [`join_codegen`](Self::join_codegen).
     fn link(
         &self,

compiler/rustc_codegen_ssa/src/traits/backend.rs

@@ -27,7 +27,6 @@ rustc_macros = { path = "../rustc_macros" }
 rustc_metadata = { path = "../rustc_metadata" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_mir_build = { path = "../rustc_mir_build" }
-rustc_mir_transform = { path = "../rustc_mir_transform" }
 rustc_parse = { path = "../rustc_parse" }
 rustc_public = { path = "../rustc_public", features = ["rustc_internal"] }
 rustc_resolve = { path = "../rustc_resolve" }

compiler/rustc_driver_impl/Cargo.toml

@@ -6,6 +6,7 @@
 
 // tidy-alphabetical-start
 #![feature(decl_macro)]
+#![feature(file_buffered)]
 #![feature(panic_backtrace_config)]
 #![feature(panic_update_hook)]
 #![feature(trim_prefix_suffix)]
@@ -333,7 +334,7 @@ pub fn run_compiler(at_args: &[String], callbacks: &mut (dyn Callbacks + Send))
             }
 
             if tcx.sess.opts.output_types.contains_key(&OutputType::Mir) {
-                if let Err(error) = rustc_mir_transform::dump_mir::emit_mir(tcx) {
+                if let Err(error) = pretty::emit_mir(tcx) {
                     tcx.dcx().emit_fatal(CantEmitMIR { error });
                 }
             }

compiler/rustc_driver_impl/src/lib.rs

@@ -2,6 +2,8 @@
 
 use std::cell::Cell;
 use std::fmt::Write;
+use std::fs::File;
+use std::io;
 
 use rustc_ast as ast;
 use rustc_ast_pretty::pprust as pprust_ast;
@@ -12,7 +14,7 @@ use rustc_middle::ty::{self, TyCtxt};
 use rustc_mir_build::thir::print::{thir_flat, thir_tree};
 use rustc_public::rustc_internal::pretty::write_smir_pretty;
 use rustc_session::Session;
-use rustc_session::config::{OutFileName, PpHirMode, PpMode, PpSourceMode};
+use rustc_session::config::{OutFileName, OutputType, PpHirMode, PpMode, PpSourceMode};
 use rustc_span::{FileName, Ident};
 use tracing::debug;
 
@@ -340,3 +342,21 @@ pub fn print<'tcx>(sess: &Session, ppm: PpMode, ex: PrintExtra<'tcx>) {
 
     write_or_print(&out, sess);
 }
+
+/// Implementation of `--emit=mir`.
+pub fn emit_mir(tcx: TyCtxt<'_>) -> io::Result<()> {
+    match tcx.output_filenames(()).path(OutputType::Mir) {
+        OutFileName::Stdout => {
+            let mut f = io::stdout();
+            write_mir_pretty(tcx, &mut f)?;
+        }
+        OutFileName::Real(path) => {
+            let mut f = File::create_buffered(&path)?;
+            write_mir_pretty(tcx, &mut f)?;
+            if tcx.sess.opts.json_artifact_notifications {
+                tcx.dcx().emit_artifact_notification(&path, "mir");
+            }
+        }
+    }
+    Ok(())
+}

compiler/rustc_driver_impl/src/pretty.rs

@@ -70,6 +70,22 @@ impl Linker {
             codegen_backend.print_statistics()
         }
 
+        if let Some(out_path) = sess.print_llvm_stats_json() {
+            let llvm_stats_json = codegen_backend.print_statistics_json();
+
+            if !llvm_stats_json.is_empty() {
+                if let Err(e) = std::fs::write(&out_path, llvm_stats_json) {
+                    sess.dcx().err(format!("failed to write stats to {}: {}", out_path, e));
+                }
+            } else {
+                sess.dcx().warn(format!(
+                    "requested to print LLVM statistics to JSON file {}, but the codegen backend \
+                    did not provide any statistics",
+                    out_path,
+                ));
+            }
+        }
+
         sess.timings.end_section(sess.dcx(), TimingSection::Codegen);
 
         if sess.opts.incremental.is_some()

compiler/rustc_interface/src/queries.rs

@@ -155,6 +155,11 @@ extern "C" void LLVMRustPrintStatistics(RustStringRef OutBuf) {
   llvm::PrintStatistics(OS);
 }
 
+extern "C" void LLVMRustPrintStatisticsJSON(RustStringRef OutBuf) {
+  auto OS = RawRustStringOstream(OutBuf);
+  llvm::PrintStatisticsJSON(OS);
+}
+
 // Some of the functions here rely on LLVM modules that may not always be
 // available. As such, we only try to build it in the first place, if
 // llvm.offload is enabled.