Auto merge of #133250 - DianQK:embed-bitcode-pgo, r=nikic

The embedded bitcode should always be prepared for LTO/ThinLTO

Fixes #115344. Fixes #117220.

There are currently two methods for generating bitcode that used for LTO. One method involves using `-C linker-plugin-lto` to emit object files as bitcode, which is the typical setting used by cargo. The other method is through `-C embed-bitcode=yes`.

When using with `-C embed-bitcode=yes -C lto=no`, we run a complete non-LTO LLVM pipeline to obtain bitcode, then the bitcode is used for LTO. We run the Call Graph Profile Pass twice on the same module.

This PR is doing something similar to LLVM's `buildFatLTODefaultPipeline`, obtaining the bitcode for embedding after running `buildThinLTOPreLinkDefaultPipeline`.

r? nikic

3 files changed, 10 insertions, 12 deletions

diff --git a/compiler/rustc_codegen_gcc/src/back/lto.rs b/compiler/rustc_codegen_gcc/src/back/lto.rs
index cb4caec8c32..e5221c7da31 100644
--- a/compiler/rustc_codegen_gcc/src/back/lto.rs
+++ b/compiler/rustc_codegen_gcc/src/back/lto.rs
@@ -632,17 +632,16 @@ pub unsafe fn optimize_thin_module(
             Arc::new(SyncContext::new(context))
         }
     };
-    let module = ModuleCodegen {
-        module_llvm: GccContext {
+    let module = ModuleCodegen::new_regular(
+        thin_module.name().to_string(),
+        GccContext {
             context,
             should_combine_object_files,
             // TODO(antoyo): use the correct relocation model here.
             relocation_model: RelocModel::Pic,
             temp_dir: None,
         },
-        name: thin_module.name().to_string(),
-        kind: ModuleKind::Regular,
-    };
+    );
     /*{
         let target = &*module.module_llvm.tm;
         let llmod = module.module_llvm.llmod();
diff --git a/compiler/rustc_codegen_gcc/src/base.rs b/compiler/rustc_codegen_gcc/src/base.rs
index 962f4b161d7..9b495174a3f 100644
--- a/compiler/rustc_codegen_gcc/src/base.rs
+++ b/compiler/rustc_codegen_gcc/src/base.rs
@@ -4,10 +4,10 @@ use std::sync::Arc;
 use std::time::Instant;
 
 use gccjit::{CType, Context, FunctionType, GlobalKind};
+use rustc_codegen_ssa::ModuleCodegen;
 use rustc_codegen_ssa::base::maybe_create_entry_wrapper;
 use rustc_codegen_ssa::mono_item::MonoItemExt;
 use rustc_codegen_ssa::traits::DebugInfoCodegenMethods;
-use rustc_codegen_ssa::{ModuleCodegen, ModuleKind};
 use rustc_middle::dep_graph;
 use rustc_middle::mir::mono::Linkage;
 #[cfg(feature = "master")]
@@ -237,16 +237,15 @@ pub fn compile_codegen_unit(
             }
         }
 
-        ModuleCodegen {
-            name: cgu_name.to_string(),
-            module_llvm: GccContext {
+        ModuleCodegen::new_regular(
+            cgu_name.to_string(),
+            GccContext {
                 context: Arc::new(SyncContext::new(context)),
                 relocation_model: tcx.sess.relocation_model(),
                 should_combine_object_files: false,
                 temp_dir: None,
             },
-            kind: ModuleKind::Regular,
-        }
+        )
     }
 
     (module, cost)
diff --git a/compiler/rustc_codegen_gcc/src/lib.rs b/compiler/rustc_codegen_gcc/src/lib.rs
index 6455bcec685..9d91aab72ab 100644
--- a/compiler/rustc_codegen_gcc/src/lib.rs
+++ b/compiler/rustc_codegen_gcc/src/lib.rs
@@ -393,7 +393,7 @@ impl WriteBackendMethods for GccCodegenBackend {
     unsafe fn optimize(
         _cgcx: &CodegenContext<Self>,
         _dcx: DiagCtxtHandle<'_>,
-        module: &ModuleCodegen<Self::Module>,
+        module: &mut ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
     ) -> Result<(), FatalError> {
         module.module_llvm.context.set_optimization_level(to_gcc_opt_level(config.opt_level));