Support -C passes in NewPM

And report an error if parsing the additional pass pipeline fails.
Threading through the error accounts for most of the changes here.

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -568,10 +568,11 @@ fn thin_lto(
 
 pub(crate) fn run_pass_manager(
     cgcx: &CodegenContext<LlvmCodegenBackend>,
+    diag_handler: &Handler,
     module: &ModuleCodegen<ModuleLlvm>,
     config: &ModuleConfig,
     thin: bool,
-) {
+) -> Result<(), FatalError> {
     let _timer = cgcx.prof.extra_verbose_generic_activity("LLVM_lto_optimize", &module.name[..]);
 
     // Now we have one massive module inside of llmod. Time to run the
@@ -584,9 +585,16 @@ pub(crate) fn run_pass_manager(
         if write::should_use_new_llvm_pass_manager(config) {
             let opt_stage = if thin { llvm::OptStage::ThinLTO } else { llvm::OptStage::FatLTO };
             let opt_level = config.opt_level.unwrap_or(config::OptLevel::No);
-            write::optimize_with_new_llvm_pass_manager(cgcx, module, config, opt_level, opt_stage);
+            write::optimize_with_new_llvm_pass_manager(
+                cgcx,
+                diag_handler,
+                module,
+                config,
+                opt_level,
+                opt_stage,
+            )?;
             debug!("lto done");
-            return;
+            return Ok(());
         }
 
         let pm = llvm::LLVMCreatePassManager();
@@ -628,6 +636,7 @@ pub(crate) fn run_pass_manager(
         llvm::LLVMDisposePassManager(pm);
     }
     debug!("lto done");
+    Ok(())
 }
 
 pub struct ModuleBuffer(&'static mut llvm::ModuleBuffer);
@@ -850,7 +859,7 @@ pub unsafe fn optimize_thin_module(
         {
             info!("running thin lto passes over {}", module.name);
             let config = cgcx.config(module.kind);
-            run_pass_manager(cgcx, &module, config, true);
+            run_pass_manager(cgcx, &diag_handler, &module, config, true)?;
             save_temp_bitcode(cgcx, &module, "thin-lto-after-pm");
         }
     }

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -415,11 +415,12 @@ pub(crate) fn should_use_new_llvm_pass_manager(config: &ModuleConfig) -> bool {
 
 pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
     cgcx: &CodegenContext<LlvmCodegenBackend>,
+    diag_handler: &Handler,
     module: &ModuleCodegen<ModuleLlvm>,
     config: &ModuleConfig,
     opt_level: config::OptLevel,
     opt_stage: llvm::OptStage,
-) {
+) -> Result<(), FatalError> {
     let unroll_loops =
         opt_level != config::OptLevel::Size && opt_level != config::OptLevel::SizeMin;
     let using_thin_buffers = opt_stage == llvm::OptStage::PreLinkThinLTO || config.bitcode_needed();
@@ -449,13 +450,12 @@ pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
         std::ptr::null_mut()
     };
 
+    let extra_passes = config.passes.join(",");
+
     // FIXME: NewPM doesn't provide a facility to pass custom InlineParams.
     // We would have to add upstream support for this first, before we can support
     // config.inline_threshold and our more aggressive default thresholds.
-    // FIXME: NewPM uses an different and more explicit way to textually represent
-    // pass pipelines. It would probably make sense to expose this, but it would
-    // require a different format than the current -C passes.
-    llvm::LLVMRustOptimizeWithNewPassManager(
+    let result = llvm::LLVMRustOptimizeWithNewPassManager(
         module.module_llvm.llmod(),
         &*module.module_llvm.tm,
         to_pass_builder_opt_level(opt_level),
@@ -477,7 +477,10 @@ pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
         llvm_selfprofiler,
         selfprofile_before_pass_callback,
         selfprofile_after_pass_callback,
+        extra_passes.as_ptr().cast(),
+        extra_passes.len(),
     );
+    result.into_result().map_err(|()| llvm_err(diag_handler, "failed to run LLVM passes"))
 }
 
 // Unsafe due to LLVM calls.
@@ -486,7 +489,7 @@ pub(crate) unsafe fn optimize(
     diag_handler: &Handler,
     module: &ModuleCodegen<ModuleLlvm>,
     config: &ModuleConfig,
-) {
+) -> Result<(), FatalError> {
     let _timer = cgcx.prof.generic_activity_with_arg("LLVM_module_optimize", &module.name[..]);
 
     let llmod = module.module_llvm.llmod();
@@ -511,8 +514,14 @@ pub(crate) unsafe fn optimize(
                 _ if cgcx.opts.cg.linker_plugin_lto.enabled() => llvm::OptStage::PreLinkThinLTO,
                 _ => llvm::OptStage::PreLinkNoLTO,
             };
-            optimize_with_new_llvm_pass_manager(cgcx, module, config, opt_level, opt_stage);
-            return;
+            return optimize_with_new_llvm_pass_manager(
+                cgcx,
+                diag_handler,
+                module,
+                config,
+                opt_level,
+                opt_stage,
+            );
         }
 
         if cgcx.prof.llvm_recording_enabled() {
@@ -647,6 +656,7 @@ pub(crate) unsafe fn optimize(
         llvm::LLVMDisposePassManager(fpm);
         llvm::LLVMDisposePassManager(mpm);
     }
+    Ok(())
 }
 
 unsafe fn add_sanitizer_passes(config: &ModuleConfig, passes: &mut Vec<&'static mut llvm::Pass>) {

compiler/rustc_codegen_llvm/src/lib.rs

@@ -162,7 +162,7 @@ impl WriteBackendMethods for LlvmCodegenBackend {
         module: &ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
     ) -> Result<(), FatalError> {
-        Ok(back::write::optimize(cgcx, diag_handler, module, config))
+        back::write::optimize(cgcx, diag_handler, module, config)
     }
     unsafe fn optimize_thin(
         cgcx: &CodegenContext<Self>,
@@ -189,8 +189,9 @@ impl WriteBackendMethods for LlvmCodegenBackend {
         module: &ModuleCodegen<Self::Module>,
         config: &ModuleConfig,
         thin: bool,
-    ) {
-        back::lto::run_pass_manager(cgcx, module, config, thin)
+    ) -> Result<(), FatalError> {
+        let diag_handler = cgcx.create_diag_handler();
+        back::lto::run_pass_manager(cgcx, &diag_handler, module, config, thin)
     }
 }
 

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -2208,7 +2208,9 @@ extern "C" {
         llvm_selfprofiler: *mut c_void,
         begin_callback: SelfProfileBeforePassCallback,
         end_callback: SelfProfileAfterPassCallback,
-    );
+        ExtraPasses: *const c_char,
+        ExtraPassesLen: size_t,
+    ) -> LLVMRustResult;
     pub fn LLVMRustPrintModule(
         M: &'a Module,
         Output: *const c_char,