Explicitly register GCOV profiling pass as well

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -473,6 +473,7 @@ pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
         pgo_gen_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
         pgo_use_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
         config.instrument_coverage,
+        config.instrument_gcov,
         llvm_selfprofiler,
         selfprofile_before_pass_callback,
         selfprofile_after_pass_callback,
@@ -546,15 +547,6 @@ pub(crate) unsafe fn optimize(
                     llvm::LLVMRustAddPass(fpm, find_pass("lint").unwrap());
                     continue;
                 }
-                if pass_name == "insert-gcov-profiling" {
-                    // Instrumentation must be inserted before optimization,
-                    // otherwise LLVM may optimize some functions away which
-                    // breaks llvm-cov.
-                    //
-                    // This mirrors what Clang does in lib/CodeGen/BackendUtil.cpp.
-                    llvm::LLVMRustAddPass(mpm, find_pass(pass_name).unwrap());
-                    continue;
-                }
 
                 if let Some(pass) = find_pass(pass_name) {
                     extra_passes.push(pass);
@@ -567,6 +559,14 @@ pub(crate) unsafe fn optimize(
                 }
             }
 
+            // Instrumentation must be inserted before optimization,
+            // otherwise LLVM may optimize some functions away which
+            // breaks llvm-cov.
+            //
+            // This mirrors what Clang does in lib/CodeGen/BackendUtil.cpp.
+            if config.instrument_gcov {
+                llvm::LLVMRustAddPass(mpm, find_pass("insert-gcov-profiling").unwrap());
+            }
             if config.instrument_coverage {
                 llvm::LLVMRustAddPass(mpm, find_pass("instrprof").unwrap());
             }

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2204,6 +2204,7 @@ extern "C" {
         PGOGenPath: *const c_char,
         PGOUsePath: *const c_char,
         InstrumentCoverage: bool,
+        InstrumentGCOV: bool,
         llvm_selfprofiler: *mut c_void,
         begin_callback: SelfProfileBeforePassCallback,
         end_callback: SelfProfileAfterPassCallback,

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -85,6 +85,7 @@ pub struct ModuleConfig {
     pub pgo_gen: SwitchWithOptPath,
     pub pgo_use: Option<PathBuf>,
     pub instrument_coverage: bool,
+    pub instrument_gcov: bool,
 
     pub sanitizer: SanitizerSet,
     pub sanitizer_recover: SanitizerSet,
@@ -166,19 +167,7 @@ impl ModuleConfig {
         };
 
         ModuleConfig {
-            passes: if_regular!(
+            passes: if_regular!(sess.opts.cg.passes.clone(), vec![]),
-                {
-                    let mut passes = sess.opts.cg.passes.clone();
-                    // compiler_builtins overrides the codegen-units settings,
-                    // which is incompatible with -Zprofile which requires that
-                    // only a single codegen unit is used per crate.
-                    if sess.opts.debugging_opts.profile && !is_compiler_builtins {
-                        passes.push("insert-gcov-profiling".to_owned());
-                    }
-                    passes
-                },
-                vec![]
-            ),
 
             opt_level: opt_level_and_size,
             opt_size: opt_level_and_size,
@@ -189,6 +178,13 @@ impl ModuleConfig {
             ),
             pgo_use: if_regular!(sess.opts.cg.profile_use.clone(), None),
             instrument_coverage: if_regular!(sess.instrument_coverage(), false),
+            instrument_gcov: if_regular!(
+                // compiler_builtins overrides the codegen-units settings,
+                // which is incompatible with -Zprofile which requires that
+                // only a single codegen unit is used per crate.
+                sess.opts.debugging_opts.profile && !is_compiler_builtins,
+                false
+            ),
 
             sanitizer: if_regular!(sess.opts.debugging_opts.sanitizer, SanitizerSet::empty()),
             sanitizer_recover: if_regular!(

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -32,6 +32,7 @@
 #include "llvm/Transforms/Instrumentation.h"
 #include "llvm/Transforms/Instrumentation/AddressSanitizer.h"
 #include "llvm/Support/TimeProfiler.h"
+#include "llvm/Transforms/Instrumentation/GCOVProfiler.h"
 #include "llvm/Transforms/Instrumentation/InstrProfiling.h"
 #include "llvm/Transforms/Instrumentation/ThreadSanitizer.h"
 #include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
@@ -745,7 +746,8 @@ LLVMRustOptimizeWithNewPassManager(
     bool MergeFunctions, bool UnrollLoops, bool SLPVectorize, bool LoopVectorize,
     bool DisableSimplifyLibCalls, bool EmitLifetimeMarkers,
     LLVMRustSanitizerOptions *SanitizerOptions,
-    const char *PGOGenPath, const char *PGOUsePath, bool InstrumentCoverage,
+    const char *PGOGenPath, const char *PGOUsePath,
+    bool InstrumentCoverage, bool InstrumentGCOV,
     void* LlvmSelfProfiler,
     LLVMRustSelfProfileBeforePassCallback BeforePassCallback,
     LLVMRustSelfProfileAfterPassCallback AfterPassCallback) {
@@ -835,6 +837,14 @@ LLVMRustOptimizeWithNewPassManager(
     );
   }
 
+  if (InstrumentGCOV) {
+    PipelineStartEPCallbacks.push_back(
+      [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
+        MPM.addPass(GCOVProfilerPass(GCOVOptions::getDefault()));
+      }
+    );
+  }
+
   if (InstrumentCoverage) {
     PipelineStartEPCallbacks.push_back(
       [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {