Auto merge of rust-lang#18208 - davidbarsky:davidbarsky/push-qkwkmttnukqt, r=lnicola

internal: allow overriding proc macro server in analysis-stats

Needed this argument in order to profile the proc macro expansion server (c.f., [this Zulip conversation](https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Frust-analyzer/topic/.60macro_rules!.60-based.20macros.20for.20derives.2Fattributes/near/473466794)). I also took the opportunity to change the phrasing for `--proc-macro-srv`.

Ran with `samply record ~/.cargo/bin/rust-analyzer analysis-stats --proc-macro-srv /Users/dbarsky/.cargo/bin/rust-analyzer-proc-macro-srv --parallel .` on rust-analyzer itself.

Author: bors

src/tools/rust-analyzer/crates/rust-analyzer/src/cli/analysis_stats.rs

@@ -81,7 +81,13 @@ impl flags::AnalysisStats {
             with_proc_macro_server: if self.disable_proc_macros {
                 ProcMacroServerChoice::None
             } else {
-                ProcMacroServerChoice::Sysroot
+                match self.proc_macro_srv {
+                    Some(ref path) => {
+                        let path = vfs::AbsPathBuf::assert_utf8(path.to_owned());
+                        ProcMacroServerChoice::Explicit(path)
+                    }
+                    None => ProcMacroServerChoice::Sysroot,
+                }
             },
             prefill_caches: false,
         };

src/tools/rust-analyzer/crates/rust-analyzer/src/cli/flags.rs

@@ -76,6 +76,8 @@ xflags::xflags! {
             optional --disable-build-scripts
             /// Don't use expand proc macros.
             optional --disable-proc-macros
+            /// Run the proc-macro-srv binary at the specified path.
+            optional --proc-macro-srv path: PathBuf
             /// Skip body lowering.
             optional --skip-lowering
             /// Skip type inference.
@@ -120,7 +122,7 @@ xflags::xflags! {
             optional --disable-build-scripts
             /// Don't use expand proc macros.
             optional --disable-proc-macros
-            /// Run a custom proc-macro-srv binary.
+            /// Run the proc-macro-srv binary at the specified path.
             optional --proc-macro-srv path: PathBuf
         }
 
@@ -133,7 +135,7 @@ xflags::xflags! {
             optional --disable-build-scripts
             /// Don't use expand proc macros.
             optional --disable-proc-macros
-            /// Run a custom proc-macro-srv binary.
+            /// Run the proc-macro-srv binary at the specified path.
             optional --proc-macro-srv path: PathBuf
         }
 
@@ -233,6 +235,7 @@ pub struct AnalysisStats {
     pub no_sysroot: bool,
     pub disable_build_scripts: bool,
     pub disable_proc_macros: bool,
+    pub proc_macro_srv: Option<PathBuf>,
     pub skip_lowering: bool,
     pub skip_inference: bool,
     pub skip_mir_stats: bool,