Support caching Clang invocations with -fprofile-use and -fprofile-instr-use. (#952)

Author: michaelwoerister

src/compiler/clang.rs

@@ -118,10 +118,14 @@ counted_array!(pub static ARGS: [ArgInfo<gcc::ArgData>; _] = [
     take_arg!("-fdebug-compilation-dir", OsString, Separated, PassThrough),
     flag!("-fmodules", TooHardFlag),
     flag!("-fno-color-diagnostics", NoDiagnosticsColorFlag),
+    flag!("-fno-profile-instr-generate", TooHardFlag),
+    flag!("-fno-profile-instr-use", TooHardFlag),
     take_arg!("-fplugin", PathBuf, CanBeConcatenated('='), ExtraHashFile),
     flag!("-fprofile-instr-generate", ProfileGenerate),
-    // Can be either -fprofile-instr-use or -fprofile-instr-use=path
-    take_arg!("-fprofile-instr-use", OsString, Concatenated, TooHard),
+    // Note: the PathBuf argument is optional
+    take_arg!("-fprofile-instr-use", PathBuf, Concatenated('='), ClangProfileUse),
+    // Note: this overrides the -fprofile-use option in gcc.rs.
+    take_arg!("-fprofile-use", PathBuf, Concatenated('='), ClangProfileUse),
     take_arg!("-fsanitize-blacklist", PathBuf, Concatenated('='), ExtraHashFile),
     take_arg!("-gcc-toolchain", OsString, Separated, PassThrough),
     take_arg!("-include-pch", PathBuf, CanBeSeparated, PreprocessorArgumentPath),
@@ -132,6 +136,27 @@ counted_array!(pub static ARGS: [ArgInfo<gcc::ArgData>; _] = [
     flag!("-verify", PreprocessorArgumentFlag),
 ]);
 
+// Maps the `-fprofile-use` argument to the actual path of the
+// .profdata file Clang will try to use.
+pub(crate) fn resolve_profile_use_path(arg: &Path, cwd: &Path) -> PathBuf {
+    // Note that `arg` might be empty (if no argument was given to
+    // -fprofile-use), in which case `path` will be `cwd` after
+    // the next statement and "./default.profdata" at the end of the
+    // block. This matches Clang's behavior for when no argument is
+    // given.
+    let mut path = cwd.join(arg);
+
+    assert!(!arg.as_os_str().is_empty() || path == cwd);
+
+    // Clang allows specifying a directory here, in which case it
+    // will look for the file `default.profdata` in that directory.
+    if path.is_dir() {
+        path.push("default.profdata");
+    }
+
+    path
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
@@ -406,4 +431,104 @@ mod test {
         let a = parses!("-c", "foo.c", "-o", "foo.o");
         assert_eq!(a.color_mode, ColorMode::Auto);
     }
+
+    #[test]
+    fn test_parse_arguments_profile_instr_use() {
+        let a = parses!(
+            "-c",
+            "foo.c",
+            "-o",
+            "foo.o",
+            "-fprofile-instr-use=foo.profdata"
+        );
+        assert_eq!(ovec!["-fprofile-instr-use=foo.profdata"], a.common_args);
+        assert_eq!(
+            ovec![std::env::current_dir().unwrap().join("foo.profdata")],
+            a.extra_hash_files
+        );
+    }
+
+    #[test]
+    fn test_parse_arguments_profile_use() {
+        let a = parses!("-c", "foo.c", "-o", "foo.o", "-fprofile-use=xyz.profdata");
+
+        assert_eq!(ovec!["-fprofile-use=xyz.profdata"], a.common_args);
+        assert_eq!(
+            ovec![std::env::current_dir().unwrap().join("xyz.profdata")],
+            a.extra_hash_files
+        );
+    }
+
+    #[test]
+    fn test_parse_arguments_profile_use_with_directory() {
+        let a = parses!("-c", "foo.c", "-o", "foo.o", "-fprofile-use=.");
+
+        assert_eq!(ovec!["-fprofile-use=."], a.common_args);
+        assert_eq!(
+            ovec![std::env::current_dir().unwrap().join("default.profdata")],
+            a.extra_hash_files
+        );
+    }
+
+    #[test]
+    fn test_parse_arguments_profile_use_with_no_argument() {
+        let a = parses!("-c", "foo.c", "-o", "foo.o", "-fprofile-use");
+
+        assert_eq!(ovec!["-fprofile-use"], a.common_args);
+        assert_eq!(
+            ovec![std::env::current_dir().unwrap().join("default.profdata")],
+            a.extra_hash_files
+        );
+    }
+
+    #[test]
+    fn test_parse_arguments_pgo_cancellation() {
+        assert_eq!(
+            CompilerArguments::CannotCache("-fno-profile-use", None),
+            parse_arguments_(stringvec![
+                "-c",
+                "foo.c",
+                "-o",
+                "foo.o",
+                "-fprofile-use",
+                "-fno-profile-use"
+            ])
+        );
+
+        assert_eq!(
+            CompilerArguments::CannotCache("-fno-profile-instr-use", None),
+            parse_arguments_(stringvec![
+                "-c",
+                "foo.c",
+                "-o",
+                "foo.o",
+                "-fprofile-instr-use",
+                "-fno-profile-instr-use"
+            ])
+        );
+
+        assert_eq!(
+            CompilerArguments::CannotCache("-fno-profile-generate", None),
+            parse_arguments_(stringvec![
+                "-c",
+                "foo.c",
+                "-o",
+                "foo.o",
+                "-fprofile-generate",
+                "-fno-profile-generate"
+            ])
+        );
+
+        assert_eq!(
+            CompilerArguments::CannotCache("-fno-profile-instr-generate", None),
+            parse_arguments_(stringvec![
+                "-c",
+                "foo.c",
+                "-o",
+                "foo.o",
+                "-fprofile-instr-generate",
+                "-fno-profile-instr-generate"
+            ])
+        );
+    }
 }

src/compiler/gcc.rs

@@ -122,6 +122,7 @@ ArgData! { pub
     Language(OsString),
     SplitDwarf,
     ProfileGenerate,
+    ClangProfileUse(PathBuf),
     TestCoverage,
     Coverage,
     ExtraHashFile(PathBuf),
@@ -168,6 +169,8 @@ counted_array!(pub static ARGS: [ArgInfo<ArgData>; _] = [
     flag!("-c", DoCompilation),
     take_arg!("-fdiagnostics-color", OsString, Concatenated('='), DiagnosticsColor),
     flag!("-fno-diagnostics-color", NoDiagnosticsColorFlag),
+    flag!("-fno-profile-generate", TooHardFlag),
+    flag!("-fno-profile-use", TooHardFlag),
     flag!("-fno-working-directory", PreprocessorArgumentFlag),
     flag!("-fplugin=libcc1plugin", TooHardFlag),
     flag!("-fprofile-arcs", ProfileGenerate),
@@ -278,6 +281,9 @@ where
                     OsString::from(arg.flag_str().expect("Compilation flag expected"));
             }
             Some(ProfileGenerate) => profile_generate = true,
+            Some(ClangProfileUse(path)) => {
+                extra_hash_files.push(clang::resolve_profile_use_path(path, cwd));
+            }
             Some(TestCoverage) => outputs_gcno = true,
             Some(Coverage) => {
                 outputs_gcno = true;
@@ -337,6 +343,7 @@ where
         let args = match arg.get_data() {
             Some(SplitDwarf)
             | Some(ProfileGenerate)
+            | Some(ClangProfileUse(_))
             | Some(TestCoverage)
             | Some(Coverage)
             | Some(DiagnosticsColor(_))
@@ -380,6 +387,7 @@ where
         let args = match arg.get_data() {
             Some(SplitDwarf)
             | Some(ProfileGenerate)
+            | Some(ClangProfileUse(_))
             | Some(TestCoverage)
             | Some(Coverage)
             | Some(DoCompilation)

src/compiler/msvc.rs

@@ -603,6 +603,12 @@ pub fn parse_arguments(
                     profile_generate = true;
                     &mut common_args
                 }
+
+                Some(ClangProfileUse(path)) => {
+                    extra_hash_files.push(clang::resolve_profile_use_path(path, cwd));
+                    &mut common_args
+                }
+
                 Some(ExtraHashFile(path)) => {
                     extra_hash_files.push(cwd.join(path));
                     &mut common_args
@@ -1061,13 +1067,15 @@ mod test {
             "-Xclang",
             "host_dictionary.obj",
             "-clang:-fprofile-generate",
+            "-clang:-fprofile-use=xyz.profdata",
             "dictionary.c"
         ];
         let ParsedArguments {
             dependency_args,
             preprocessor_args,
             common_args,
             profile_generate,
+            extra_hash_files,
             ..
         } = match parse_arguments(args) {
             CompilerArguments::Ok(args) => args,
@@ -1090,7 +1098,17 @@ mod test {
                 "host_dictionary.obj"
             )
         );
-        assert_eq!(common_args, ovec!("-clang:-fprofile-generate"));
+        assert_eq!(
+            common_args,
+            ovec!(
+                "-clang:-fprofile-generate",
+                "-clang:-fprofile-use=xyz.profdata"
+            )
+        );
+        assert_eq!(
+            extra_hash_files,
+            ovec!(std::env::current_dir().unwrap().join("xyz.profdata"))
+        );
     }
 
     #[test]