Auto merge of #34715 - scottcarr:mir-test, r=nikomatsakis

Add MIR Optimization Tests

I've starting working on the infrastructure for testing MIR optimizations.

The plan now is to have a set of test cases (written in Rust), compile them with -Z dump-mir, and check the MIR before and after each pass.

Author: bors

mk/tests.mk

@@ -277,7 +277,8 @@ check-stage$(1)-T-$(2)-H-$(3)-exec: \
 	check-stage$(1)-T-$(2)-H-$(3)-ui-exec \
 	check-stage$(1)-T-$(2)-H-$(3)-doc-exec \
 	check-stage$(1)-T-$(2)-H-$(3)-doc-error-index-exec \
-	check-stage$(1)-T-$(2)-H-$(3)-pretty-exec
+	check-stage$(1)-T-$(2)-H-$(3)-pretty-exec \
+	check-stage$(1)-T-$(2)-H-$(3)-mir-opt-exec
 
 ifndef CFG_DISABLE_CODEGEN_TESTS
 check-stage$(1)-T-$(2)-H-$(3)-exec: \
@@ -458,6 +459,7 @@ UI_RS := $(call rwildcard,$(S)src/test/ui/,*.rs) \
          $(call rwildcard,$(S)src/test/ui/,*.stdout) \
          $(call rwildcard,$(S)src/test/ui/,*.stderr)
 RUSTDOCCK_RS := $(call rwildcard,$(S)src/test/rustdoc/,*.rs)
+MIR_OPT_RS := $(call rwildcard,$(S)src/test/mir-opt/,*.rs)
 
 RPASS_TESTS := $(RPASS_RS)
 RPASS_VALGRIND_TESTS := $(RPASS_VALGRIND_RS)
@@ -475,6 +477,7 @@ CODEGEN_UNITS_TESTS := $(CODEGEN_UNITS_RS)
 INCREMENTAL_TESTS := $(INCREMENTAL_RS)
 RMAKE_TESTS := $(RMAKE_RS)
 UI_TESTS := $(UI_RS)
+MIR_OPT_TESTS := $(MIR_OPT_RS)
 RUSTDOCCK_TESTS := $(RUSTDOCCK_RS)
 
 CTEST_SRC_BASE_rpass = run-pass
@@ -552,6 +555,11 @@ CTEST_BUILD_BASE_ui = ui
 CTEST_MODE_ui = ui
 CTEST_RUNTOOL_ui = $(CTEST_RUNTOOL)
 
+CTEST_SRC_BASE_mir-opt = mir-opt
+CTEST_BUILD_BASE_mir-opt = mir-opt
+CTEST_MODE_mir-opt = mir-opt
+CTEST_RUNTOOL_mir-opt = $(CTEST_RUNTOOL)
+
 CTEST_SRC_BASE_rustdocck = rustdoc
 CTEST_BUILD_BASE_rustdocck = rustdoc
 CTEST_MODE_rustdocck = rustdoc
@@ -684,6 +692,7 @@ CTEST_DEPS_incremental_$(1)-T-$(2)-H-$(3) = $$(INCREMENTAL_TESTS)
 CTEST_DEPS_rmake_$(1)-T-$(2)-H-$(3) = $$(RMAKE_TESTS) \
 	$$(CSREQ$(1)_T_$(3)_H_$(3)) $$(SREQ$(1)_T_$(2)_H_$(3))
 CTEST_DEPS_ui_$(1)-T-$(2)-H-$(3) = $$(UI_TESTS)
+CTEST_DEPS_mir-opt_$(1)-T-$(2)-H-$(3) = $$(MIR_OPT_TESTS)
 CTEST_DEPS_rustdocck_$(1)-T-$(2)-H-$(3) = $$(RUSTDOCCK_TESTS) \
 		$$(HBIN$(1)_H_$(3))/rustdoc$$(X_$(3)) \
 		$(S)src/etc/htmldocck.py
@@ -755,7 +764,7 @@ endef
 
 CTEST_NAMES = rpass rpass-valgrind rpass-full rfail-full cfail-full rfail cfail pfail \
 	debuginfo-gdb debuginfo-lldb codegen codegen-units rustdocck incremental \
-	rmake ui
+	rmake ui mir-opt
 
 $(foreach host,$(CFG_HOST), \
  $(eval $(foreach target,$(CFG_TARGET), \
@@ -964,6 +973,7 @@ TEST_GROUPS = \
 	pretty-rfail-full \
 	pretty-rfail \
 	pretty-pretty \
+	mir-opt \
 	$(NULL)
 
 define DEF_CHECK_FOR_STAGE_AND_TARGET_AND_HOST

src/bootstrap/lib.rs

@@ -388,6 +388,10 @@ impl Build {
                     check::compiletest(self, &compiler, target.target,
                                        "pretty", "run-pass-valgrind");
                 }
+                CheckMirOpt { compiler } => {
+                    check::compiletest(self, &compiler, target.target,
+                                       "mir-opt", "mir-opt");
+                }
                 CheckCodegen { compiler } => {
                     check::compiletest(self, &compiler, target.target,
                                        "codegen", "codegen");

src/bootstrap/step.rs

@@ -124,6 +124,7 @@ macro_rules! targets {
             (check_codegen_units, CheckCodegenUnits { compiler: Compiler<'a> }),
             (check_incremental, CheckIncremental { compiler: Compiler<'a> }),
             (check_ui, CheckUi { compiler: Compiler<'a> }),
+            (check_mir_opt, CheckMirOpt { compiler: Compiler<'a> }),
             (check_debuginfo, CheckDebuginfo { compiler: Compiler<'a> }),
             (check_rustdoc, CheckRustdoc { compiler: Compiler<'a> }),
             (check_docs, CheckDocs { compiler: Compiler<'a> }),
@@ -450,6 +451,7 @@ impl<'a> Step<'a> {
                         self.check_pretty_rfail_full(compiler),
                         self.check_rpass_valgrind(compiler),
                         self.check_rmake(compiler),
+                        self.check_mir_opt(compiler),
 
                         // crates
                         self.check_crate_rustc(compiler),
@@ -477,6 +479,7 @@ impl<'a> Step<'a> {
             Source::CheckTidy { stage } => {
                 vec![self.tool_tidy(stage)]
             }
+            Source::CheckMirOpt { compiler} |
             Source::CheckPrettyRPass { compiler } |
             Source::CheckPrettyRFail { compiler } |
             Source::CheckRFail { compiler } |

src/librustc/session/config.rs

@@ -747,6 +747,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
           "set the MIR optimization level (0-3)"),
     dump_mir: Option<String> = (None, parse_opt_string,
           "dump MIR state at various points in translation"),
+    dump_mir_dir: Option<String> = (None, parse_opt_string,
+          "the directory the MIR is dumped into"),
     orbit: bool = (false, parse_bool,
           "get MIR where it belongs - everywhere; most importantly, in orbit"),
 }

src/librustc_mir/pretty.rs

@@ -19,6 +19,7 @@ use std::fmt::Display;
 use std::fs;
 use std::io::{self, Write};
 use syntax::ast::NodeId;
+use std::path::{PathBuf, Path};
 
 const INDENT: &'static str = "    ";
 /// Alignment for lining up comments following MIR statements
@@ -66,9 +67,15 @@ pub fn dump_mir<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         _ => String::new()
     };
 
+    let mut file_path = PathBuf::new();
+    if let Some(ref file_dir) = tcx.sess.opts.debugging_opts.dump_mir_dir {
+        let p = Path::new(file_dir);
+        file_path.push(p);
+    };
     let file_name = format!("rustc.node{}{}.{}.{}.mir",
                             node_id, promotion_id, pass_name, disambiguator);
-    let _ = fs::File::create(&file_name).and_then(|mut file| {
+    file_path.push(&file_name);
+    let _ = fs::File::create(&file_path).and_then(|mut file| {
         try!(writeln!(file, "// MIR for `{}`", node_path));
         try!(writeln!(file, "// node_id = {}", node_id));
         try!(writeln!(file, "// pass_name = {}", pass_name));

src/test/mir-opt/README.md

@@ -0,0 +1,44 @@
+This folder contains tests for MIR optimizations.
+
+The test format is:
+
+```
+(arbitrary rust code)
+// END RUST SOURCE
+// START $file_name_of_some_mir_dump_0
+//  $expected_line_0
+// ...
+// $expected_line_N
+// END $file_name_of_some_mir_dump_0
+// ...
+// START $file_name_of_some_mir_dump_N
+//  $expected_line_0
+// ...
+// $expected_line_N
+// END $file_name_of_some_mir_dump_N
+```
+
+All the test information is in comments so the test is runnable.
+
+For each $file_name, compiletest expects [$expected_line_0, ...,
+$expected_line_N] to appear in the dumped MIR in order.  Currently it allows
+other non-matched lines before, after and in-between.  
+
+Lines match ignoring whitespace, and the prefix "//" is removed.
+
+It also currently strips trailing comments -- partly because the full file path
+in "scope comments" is unpredictable and partly because tidy complains about
+the lines being too long.
+
+compiletest handles dumping the MIR before and after every pass for you.  The
+test writer only has to specify the file names of the dumped files (not the
+full path to the file) and what lines to expect.  I added an option to rustc
+that tells it to dump the mir into some directly (rather then always dumping to
+the current directory).  
+
+Lines match ignoring whitespace, and the prefix "//" is removed of course.
+
+It also currently strips trailing comments -- partly because the full file path
+in "scope comments" is unpredictable and partly because tidy complains about
+the lines being too long.
+

src/test/mir-opt/return_an_array.rs

@@ -0,0 +1,18 @@
+// Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// this tests move up progration, which is not yet implemented
+
+fn foo() -> [u8; 1024] {
+        let x = [0; 1024];
+        return x;
+}
+
+fn main() { }

src/test/mir-opt/simplify_if.rs

@@ -0,0 +1,27 @@
+// Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    if false {
+        println!("hello world!");
+    }
+}
+
+// END RUST SOURCE
+// START rustc.node4.SimplifyBranches.initial-before.mir
+// bb0: {
+//     if(const false) -> [true: bb1, false: bb2]; // scope 0 at simplify_if.rs:12:5: 14:6
+// }
+// END rustc.node4.SimplifyBranches.initial-before.mir
+// START rustc.node4.SimplifyBranches.initial-after.mir
+// bb0: {
+//     goto -> bb2;                     // scope 0 at simplify_if.rs:12:5: 14:6
+// }
+// END rustc.node4.SimplifyBranches.initial-after.mir

src/tools/compiletest/src/common.rs

@@ -29,6 +29,7 @@ pub enum Mode {
     Incremental,
     RunMake,
     Ui,
+    MirOpt,
 }
 
 impl FromStr for Mode {
@@ -49,6 +50,7 @@ impl FromStr for Mode {
           "incremental" => Ok(Incremental),
           "run-make" => Ok(RunMake),
           "ui" => Ok(Ui),
+          "mir-opt" => Ok(MirOpt),
           _ => Err(()),
         }
     }
@@ -71,6 +73,7 @@ impl fmt::Display for Mode {
             Incremental => "incremental",
             RunMake => "run-make",
             Ui => "ui",
+            MirOpt => "mir-opt",
         }, f)
     }
 }

src/tools/compiletest/src/main.rs

@@ -86,7 +86,7 @@ pub fn parse_config(args: Vec<String> ) -> Config {
           reqopt("", "stage-id", "the target-stage identifier", "stageN-TARGET"),
           reqopt("", "mode", "which sort of compile tests to run",
                  "(compile-fail|parse-fail|run-fail|run-pass|\
-                  run-pass-valgrind|pretty|debug-info|incremental)"),
+                  run-pass-valgrind|pretty|debug-info|incremental|mir-opt)"),
           optflag("", "ignored", "run tests marked as ignored"),
           optopt("", "runtool", "supervisor program to run tests under \
                                  (eg. emulator, valgrind)", "PROGRAM"),