Rollup merge of #73893 - ajpaverd:cfguard-stabilize, r=nikomatsakis

[rust.git] / src / librustc_session / config.rs

diff --git a/src/librustc_session/config.rs b/src/librustc_session/config.rs
index dbf5b7ece08fee5cf44105af2ab7b38727c73370..620a04b45b0e4c457823af78a21d1bc9abf2b38b 100644 (file)
--- a/src/librustc_session/config.rs
+++ b/src/librustc_session/config.rs
@@ -717,18 +717,20 @@ pub fn default_configuration(sess: &Session) -> CrateConfig {
     let mut ret = FxHashSet::default();
     ret.reserve(6); // the minimum number of insertions
     // Target bindings.
-    ret.insert((Symbol::intern("target_os"), Some(Symbol::intern(os))));
+    ret.insert((sym::target_os, Some(Symbol::intern(os))));
     if let Some(ref fam) = sess.target.target.options.target_family {
-        ret.insert((Symbol::intern("target_family"), Some(Symbol::intern(fam))));
-        if fam == "windows" || fam == "unix" {
-            ret.insert((Symbol::intern(fam), None));
+        ret.insert((sym::target_family, Some(Symbol::intern(fam))));
+        if fam == "windows" {
+            ret.insert((sym::windows, None));
+        } else if fam == "unix" {
+            ret.insert((sym::unix, None));
         }
     }
-    ret.insert((Symbol::intern("target_arch"), Some(Symbol::intern(arch))));
-    ret.insert((Symbol::intern("target_endian"), Some(Symbol::intern(end))));
-    ret.insert((Symbol::intern("target_pointer_width"), Some(Symbol::intern(wordsz))));
-    ret.insert((Symbol::intern("target_env"), Some(Symbol::intern(env))));
-    ret.insert((Symbol::intern("target_vendor"), Some(Symbol::intern(vendor))));
+    ret.insert((sym::target_arch, Some(Symbol::intern(arch))));
+    ret.insert((sym::target_endian, Some(Symbol::intern(end))));
+    ret.insert((sym::target_pointer_width, Some(Symbol::intern(wordsz))));
+    ret.insert((sym::target_env, Some(Symbol::intern(env))));
+    ret.insert((sym::target_vendor, Some(Symbol::intern(vendor))));
     if sess.target.target.options.has_elf_tls {
         ret.insert((sym::target_thread_local, None));
     }
@@ -754,7 +756,7 @@ pub fn default_configuration(sess: &Session) -> CrateConfig {
     }
 
     if sess.opts.debug_assertions {
-        ret.insert((Symbol::intern("debug_assertions"), None));
+        ret.insert((sym::debug_assertions, None));
     }
     if sess.opts.crate_types.contains(&CrateType::ProcMacro) {
         ret.insert((sym::proc_macro, None));
@@ -1705,6 +1707,31 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         );
     }
 
+    if debugging_opts.instrument_coverage {
+        if cg.profile_generate.enabled() || cg.profile_use.is_some() {
+            early_error(
+                error_format,
+                "option `-Z instrument-coverage` is not compatible with either `-C profile-use` \
+                or `-C profile-generate`",
+            );
+        }
+
+        // `-Z instrument-coverage` implies:
+        //   * `-Z symbol-mangling-version=v0` - to ensure consistent and reversable name mangling.
+        //     Note, LLVM coverage tools can analyze coverage over multiple runs, including some
+        //     changes to source code; so mangled names must be consistent across compilations.
+        //   * `-C link-dead-code` - so unexecuted code is still counted as zero, rather than be
+        //     optimized out. Note that instrumenting dead code can be explicitly disabled with:
+        //         `-Z instrument-coverage -C link-dead-code=no`.
+        debugging_opts.symbol_mangling_version = SymbolManglingVersion::V0;
+        if cg.link_dead_code == None {
+            // FIXME(richkadel): Investigate if the `instrument-coverage` implementation can
+            // inject ["zero counters"](https://llvm.org/docs/CoverageMappingFormat.html#counter)
+            // in the coverage map when "dead code" is removed, rather than forcing `link-dead-code`.
+            cg.link_dead_code = Some(true);
+        }
+    }
+
     if !cg.embed_bitcode {
         match cg.lto {
             LtoCli::No | LtoCli::Unspecified => {}