compiler/rustc_codegen_gcc/src/lib.rs - toolchain/rustc - Git at Google

 /*
  * TODO(antoyo): implement equality in libgccjit based on https://zpz.github.io/blog/overloading-equality-operator-in-cpp-class-hierarchy/ (for type equality?)
  * TODO(antoyo): support #[inline] attributes.
  * TODO(antoyo): support LTO (gcc's equivalent to Thin LTO is enabled by -fwhopr: https://stackoverflow.com/questions/64954525/does-gcc-have-thin-lto).
  *
  * TODO(antoyo): remove the patches.
  */

 #![feature(
     rustc_private,
     decl_macro,
     associated_type_bounds,
     never_type,
     trusted_len,
     hash_raw_entry
 )]
 #![allow(broken_intra_doc_links)]
 #![recursion_limit="256"]
 #![warn(rust_2018_idioms)]
 #![warn(unused_lifetimes)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]

 extern crate rustc_apfloat;
 extern crate rustc_ast;
 extern crate rustc_codegen_ssa;
 extern crate rustc_data_structures;
 extern crate rustc_errors;
 extern crate rustc_hir;
 extern crate rustc_macros;
 extern crate rustc_metadata;
 extern crate rustc_middle;
 extern crate rustc_session;
 extern crate rustc_span;
 extern crate rustc_target;
 extern crate tempfile;

 // This prevents duplicating functions and statics that are already part of the host rustc process.
 #[allow(unused_extern_crates)]
 extern crate rustc_driver;

 mod abi;
 mod allocator;
 mod archive;
 mod asm;
 mod back;
 mod base;
 mod builder;
 mod callee;
 mod common;
 mod consts;
 mod context;
 mod coverageinfo;
 mod debuginfo;
 mod declare;
 mod errors;
 mod int;
 mod intrinsic;
 mod mono_item;
 mod type_;
 mod type_of;

 use std::any::Any;
 use std::sync::{Arc, Mutex};

 use crate::errors::LTONotSupported;
 use gccjit::{Context, OptimizationLevel, CType};
 use rustc_ast::expand::allocator::AllocatorKind;
 use rustc_codegen_ssa::{CodegenResults, CompiledModule, ModuleCodegen};
 use rustc_codegen_ssa::base::codegen_crate;
 use rustc_codegen_ssa::back::write::{CodegenContext, FatLTOInput, ModuleConfig, TargetMachineFactoryFn};
 use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
 use rustc_codegen_ssa::target_features::supported_target_features;
 use rustc_codegen_ssa::traits::{CodegenBackend, ExtraBackendMethods, ModuleBufferMethods, ThinBufferMethods, WriteBackendMethods};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{ErrorGuaranteed, Handler};
 use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::ty::query::Providers;
 use rustc_session::config::{Lto, OptLevel, OutputFilenames};
 use rustc_session::Session;
 use rustc_span::Symbol;
 use rustc_span::fatal_error::FatalError;
 use tempfile::TempDir;

 pub struct PrintOnPanic<F: Fn() -> String>(pub F);

 impl<F: Fn() -> String> Drop for PrintOnPanic<F> {
     fn drop(&mut self) {
         if ::std::thread::panicking() {
             println!("{}", (self.0)());
         }
     }
 }

 #[derive(Clone)]
 pub struct GccCodegenBackend {
     supports_128bit_integers: Arc<Mutex<bool>>,
 }

 impl CodegenBackend for GccCodegenBackend {
     fn init(&self, sess: &Session) {
         if sess.lto() != Lto::No {
             sess.emit_warning(LTONotSupported {});
         }

         let temp_dir = TempDir::new().expect("cannot create temporary directory");
         let temp_file = temp_dir.into_path().join("result.asm");
         let check_context = Context::default();
         check_context.set_print_errors_to_stderr(false);
         let _int128_ty = check_context.new_c_type(CType::UInt128t);
         // NOTE: we cannot just call compile() as this would require other files than libgccjit.so.
         check_context.compile_to_file(gccjit::OutputKind::Assembler, temp_file.to_str().expect("path to str"));
         *self.supports_128bit_integers.lock().expect("lock") = check_context.get_last_error() == Ok(None);
     }

     fn provide(&self, providers: &mut Providers) {
         // FIXME(antoyo) compute list of enabled features from cli flags
         providers.global_backend_features = |_tcx, ()| vec![];
     }

     fn codegen_crate<'tcx>(&self, tcx: TyCtxt<'tcx>, metadata: EncodedMetadata, need_metadata_module: bool) -> Box<dyn Any> {
         let target_cpu = target_cpu(tcx.sess);
         let res = codegen_crate(self.clone(), tcx, target_cpu.to_string(), metadata, need_metadata_module);

         Box::new(res)
     }

     fn join_codegen(&self, ongoing_codegen: Box<dyn Any>, sess: &Session, _outputs: &OutputFilenames) -> Result<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>), ErrorGuaranteed> {
         let (codegen_results, work_products) = ongoing_codegen
             .downcast::<rustc_codegen_ssa::back::write::OngoingCodegen<GccCodegenBackend>>()
             .expect("Expected GccCodegenBackend's OngoingCodegen, found Box<Any>")
             .join(sess);

         Ok((codegen_results, work_products))
     }

     fn link(&self, sess: &Session, codegen_results: CodegenResults, outputs: &OutputFilenames) -> Result<(), ErrorGuaranteed> {
         use rustc_codegen_ssa::back::link::link_binary;

         link_binary(
             sess,
             &crate::archive::ArArchiveBuilderBuilder,
             &codegen_results,
             outputs,
         )
     }

     fn target_features(&self, sess: &Session, allow_unstable: bool) -> Vec<Symbol> {
         target_features(sess, allow_unstable)
     }
 }

 impl ExtraBackendMethods for GccCodegenBackend {
     fn codegen_allocator<'tcx>(&self, tcx: TyCtxt<'tcx>, module_name: &str, kind: AllocatorKind, has_alloc_error_handler: bool) -> Self::Module {
         let mut mods = GccContext {
             context: Context::default(),
         };
         unsafe { allocator::codegen(tcx, &mut mods, module_name, kind, has_alloc_error_handler); }
         mods
     }

     fn compile_codegen_unit<'tcx>(&self, tcx: TyCtxt<'tcx>, cgu_name: Symbol) -> (ModuleCodegen<Self::Module>, u64) {
         base::compile_codegen_unit(tcx, cgu_name, *self.supports_128bit_integers.lock().expect("lock"))
     }

     fn target_machine_factory(&self, _sess: &Session, _opt_level: OptLevel, _features: &[String]) -> TargetMachineFactoryFn<Self> {
         // TODO(antoyo): set opt level.
         Arc::new(|_| {
             Ok(())
         })
     }
 }

 pub struct ModuleBuffer;

 impl ModuleBufferMethods for ModuleBuffer {
     fn data(&self) -> &[u8] {
         unimplemented!();
     }
 }

 pub struct ThinBuffer;

 impl ThinBufferMethods for ThinBuffer {
     fn data(&self) -> &[u8] {
         unimplemented!();
     }
 }

 pub struct GccContext {
     context: Context<'static>,
 }

 unsafe impl Send for GccContext {}
 // FIXME(antoyo): that shouldn't be Sync. Parallel compilation is currently disabled with "-Zno-parallel-llvm". Try to disable it here.
 unsafe impl Sync for GccContext {}

 impl WriteBackendMethods for GccCodegenBackend {
     type Module = GccContext;
     type TargetMachine = ();
     type ModuleBuffer = ModuleBuffer;
     type ThinData = ();
     type ThinBuffer = ThinBuffer;

     fn run_fat_lto(_cgcx: &CodegenContext<Self>, mut modules: Vec<FatLTOInput<Self>>, _cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>) -> Result<LtoModuleCodegen<Self>, FatalError> {
         // TODO(antoyo): implement LTO by sending -flto to libgccjit and adding the appropriate gcc linker plugins.
         // NOTE: implemented elsewhere.
         // TODO(antoyo): what is implemented elsewhere ^ ?
         let module =
             match modules.remove(0) {
                 FatLTOInput::InMemory(module) => module,
                 FatLTOInput::Serialized { .. } => {
                     unimplemented!();
                 }
             };
         Ok(LtoModuleCodegen::Fat { module, _serialized_bitcode: vec![] })
     }

     fn run_thin_lto(_cgcx: &CodegenContext<Self>, _modules: Vec<(String, Self::ThinBuffer)>, _cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>) -> Result<(Vec<LtoModuleCodegen<Self>>, Vec<WorkProduct>), FatalError> {
         unimplemented!();
     }

     fn print_pass_timings(&self) {
         unimplemented!();
     }

     unsafe fn optimize(_cgcx: &CodegenContext<Self>, _diag_handler: &Handler, module: &ModuleCodegen<Self::Module>, config: &ModuleConfig) -> Result<(), FatalError> {
         module.module_llvm.context.set_optimization_level(to_gcc_opt_level(config.opt_level));
         Ok(())
     }

     fn optimize_fat(_cgcx: &CodegenContext<Self>, _module: &mut ModuleCodegen<Self::Module>) -> Result<(), FatalError> {
         // TODO(antoyo)
         Ok(())
     }

     unsafe fn optimize_thin(_cgcx: &CodegenContext<Self>, _thin: ThinModule<Self>) -> Result<ModuleCodegen<Self::Module>, FatalError> {
         unimplemented!();
     }

     unsafe fn codegen(cgcx: &CodegenContext<Self>, diag_handler: &Handler, module: ModuleCodegen<Self::Module>, config: &ModuleConfig) -> Result<CompiledModule, FatalError> {
         back::write::codegen(cgcx, diag_handler, module, config)
     }

     fn prepare_thin(_module: ModuleCodegen<Self::Module>) -> (String, Self::ThinBuffer) {
         unimplemented!();
     }

     fn serialize_module(_module: ModuleCodegen<Self::Module>) -> (String, Self::ModuleBuffer) {
         unimplemented!();
     }

     fn run_link(cgcx: &CodegenContext<Self>, diag_handler: &Handler, modules: Vec<ModuleCodegen<Self::Module>>) -> Result<ModuleCodegen<Self::Module>, FatalError> {
         back::write::link(cgcx, diag_handler, modules)
     }
 }

 /// This is the entrypoint for a hot plugged rustc_codegen_gccjit
 #[no_mangle]
 pub fn __rustc_codegen_backend() -> Box<dyn CodegenBackend> {
     Box::new(GccCodegenBackend {
         supports_128bit_integers: Arc::new(Mutex::new(false)),
     })
 }

 fn to_gcc_opt_level(optlevel: Option<OptLevel>) -> OptimizationLevel {
     match optlevel {
         None => OptimizationLevel::None,
         Some(level) => {
             match level {
                 OptLevel::No => OptimizationLevel::None,
                 OptLevel::Less => OptimizationLevel::Limited,
                 OptLevel::Default => OptimizationLevel::Standard,
                 OptLevel::Aggressive => OptimizationLevel::Aggressive,
                 OptLevel::Size | OptLevel::SizeMin => OptimizationLevel::Limited,
             }
         },
     }
 }

 fn handle_native(name: &str) -> &str {
     if name != "native" {
         return name;
     }

     unimplemented!();
 }

 pub fn target_cpu(sess: &Session) -> &str {
     match sess.opts.cg.target_cpu {
         Some(ref name) => handle_native(name),
         None => handle_native(sess.target.cpu.as_ref()),
     }
 }

 pub fn target_features(sess: &Session, allow_unstable: bool) -> Vec<Symbol> {
     supported_target_features(sess)
         .iter()
         .filter_map(
             |&(feature, gate)| {
                 if sess.is_nightly_build() || allow_unstable || gate.is_none() { Some(feature) } else { None }
             },
         )
         .filter(|_feature| {
             // TODO(antoyo): implement a way to get enabled feature in libgccjit.
             // Probably using the equivalent of __builtin_cpu_supports.
             #[cfg(feature="master")]
             {
                 _feature.contains("sse") || _feature.contains("avx")
             }
             #[cfg(not(feature="master"))]
             {
                 false
             }
             /*
                adx, aes, avx, avx2, avx512bf16, avx512bitalg, avx512bw, avx512cd, avx512dq, avx512er, avx512f, avx512gfni,
                avx512ifma, avx512pf, avx512vaes, avx512vbmi, avx512vbmi2, avx512vl, avx512vnni, avx512vp2intersect, avx512vpclmulqdq,
                avx512vpopcntdq, bmi1, bmi2, cmpxchg16b, ermsb, f16c, fma, fxsr, lzcnt, movbe, pclmulqdq, popcnt, rdrand, rdseed, rtm,
                sha, sse, sse2, sse3, sse4.1, sse4.2, sse4a, ssse3, tbm, xsave, xsavec, xsaveopt, xsaves
              */
             //false
         })
         .map(|feature| Symbol::intern(feature))
         .collect()
 }
	/*
	* TODO(antoyo): implement equality in libgccjit based on https://zpz.github.io/blog/overloading-equality-operator-in-cpp-class-hierarchy/ (for type equality?)
	* TODO(antoyo): support #[inline] attributes.
	* TODO(antoyo): support LTO (gcc's equivalent to Thin LTO is enabled by -fwhopr: https://stackoverflow.com/questions/64954525/does-gcc-have-thin-lto).
	*
	* TODO(antoyo): remove the patches.
	*/

	#![feature(
	rustc_private,
	decl_macro,
	associated_type_bounds,
	never_type,
	trusted_len,
	hash_raw_entry
	)]
	#![allow(broken_intra_doc_links)]
	#![recursion_limit="256"]
	#![warn(rust_2018_idioms)]
	#![warn(unused_lifetimes)]
	#![deny(rustc::untranslatable_diagnostic)]
	#![deny(rustc::diagnostic_outside_of_impl)]

	extern crate rustc_apfloat;
	extern crate rustc_ast;
	extern crate rustc_codegen_ssa;
	extern crate rustc_data_structures;
	extern crate rustc_errors;
	extern crate rustc_hir;
	extern crate rustc_macros;
	extern crate rustc_metadata;
	extern crate rustc_middle;
	extern crate rustc_session;
	extern crate rustc_span;
	extern crate rustc_target;
	extern crate tempfile;

	// This prevents duplicating functions and statics that are already part of the host rustc process.
	#[allow(unused_extern_crates)]
	extern crate rustc_driver;

	mod abi;
	mod allocator;
	mod archive;
	mod asm;
	mod back;
	mod base;
	mod builder;
	mod callee;
	mod common;
	mod consts;
	mod context;
	mod coverageinfo;
	mod debuginfo;
	mod declare;
	mod errors;
	mod int;
	mod intrinsic;
	mod mono_item;
	mod type_;
	mod type_of;

	use std::any::Any;
	use std::sync::{Arc, Mutex};

	use crate::errors::LTONotSupported;
	use gccjit::{Context, OptimizationLevel, CType};
	use rustc_ast::expand::allocator::AllocatorKind;
	use rustc_codegen_ssa::{CodegenResults, CompiledModule, ModuleCodegen};
	use rustc_codegen_ssa::base::codegen_crate;
	use rustc_codegen_ssa::back::write::{CodegenContext, FatLTOInput, ModuleConfig, TargetMachineFactoryFn};
	use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
	use rustc_codegen_ssa::target_features::supported_target_features;
	use rustc_codegen_ssa::traits::{CodegenBackend, ExtraBackendMethods, ModuleBufferMethods, ThinBufferMethods, WriteBackendMethods};
	use rustc_data_structures::fx::FxHashMap;
	use rustc_errors::{ErrorGuaranteed, Handler};
	use rustc_metadata::EncodedMetadata;
	use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
	use rustc_middle::ty::TyCtxt;
	use rustc_middle::ty::query::Providers;
	use rustc_session::config::{Lto, OptLevel, OutputFilenames};
	use rustc_session::Session;
	use rustc_span::Symbol;
	use rustc_span::fatal_error::FatalError;
	use tempfile::TempDir;

	pub struct PrintOnPanic<F: Fn() -> String>(pub F);

	impl<F: Fn() -> String> Drop for PrintOnPanic<F> {
	fn drop(&mut self) {
	if ::std::thread::panicking() {
	println!("{}", (self.0)());
	}
	}
	}

	#[derive(Clone)]
	pub struct GccCodegenBackend {
	supports_128bit_integers: Arc<Mutex<bool>>,
	}

	impl CodegenBackend for GccCodegenBackend {
	fn init(&self, sess: &Session) {
	if sess.lto() != Lto::No {
	sess.emit_warning(LTONotSupported {});
	}

	let temp_dir = TempDir::new().expect("cannot create temporary directory");
	let temp_file = temp_dir.into_path().join("result.asm");
	let check_context = Context::default();
	check_context.set_print_errors_to_stderr(false);
	let _int128_ty = check_context.new_c_type(CType::UInt128t);
	// NOTE: we cannot just call compile() as this would require other files than libgccjit.so.
	check_context.compile_to_file(gccjit::OutputKind::Assembler, temp_file.to_str().expect("path to str"));
	*self.supports_128bit_integers.lock().expect("lock") = check_context.get_last_error() == Ok(None);
	}

	fn provide(&self, providers: &mut Providers) {
	// FIXME(antoyo) compute list of enabled features from cli flags
	providers.global_backend_features = \|_tcx, ()\| vec![];
	}

	fn codegen_crate<'tcx>(&self, tcx: TyCtxt<'tcx>, metadata: EncodedMetadata, need_metadata_module: bool) -> Box<dyn Any> {
	let target_cpu = target_cpu(tcx.sess);
	let res = codegen_crate(self.clone(), tcx, target_cpu.to_string(), metadata, need_metadata_module);

	Box::new(res)
	}

	fn join_codegen(&self, ongoing_codegen: Box<dyn Any>, sess: &Session, _outputs: &OutputFilenames) -> Result<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>), ErrorGuaranteed> {
	let (codegen_results, work_products) = ongoing_codegen
	.downcast::<rustc_codegen_ssa::back::write::OngoingCodegen<GccCodegenBackend>>()
	.expect("Expected GccCodegenBackend's OngoingCodegen, found Box<Any>")
	.join(sess);

	Ok((codegen_results, work_products))
	}

	fn link(&self, sess: &Session, codegen_results: CodegenResults, outputs: &OutputFilenames) -> Result<(), ErrorGuaranteed> {
	use rustc_codegen_ssa::back::link::link_binary;

	link_binary(
	sess,
	&crate::archive::ArArchiveBuilderBuilder,
	&codegen_results,
	outputs,
	)
	}

	fn target_features(&self, sess: &Session, allow_unstable: bool) -> Vec<Symbol> {
	target_features(sess, allow_unstable)
	}
	}

	impl ExtraBackendMethods for GccCodegenBackend {
	fn codegen_allocator<'tcx>(&self, tcx: TyCtxt<'tcx>, module_name: &str, kind: AllocatorKind, has_alloc_error_handler: bool) -> Self::Module {
	let mut mods = GccContext {
	context: Context::default(),
	};
	unsafe { allocator::codegen(tcx, &mut mods, module_name, kind, has_alloc_error_handler); }
	mods
	}

	fn compile_codegen_unit<'tcx>(&self, tcx: TyCtxt<'tcx>, cgu_name: Symbol) -> (ModuleCodegen<Self::Module>, u64) {
	base::compile_codegen_unit(tcx, cgu_name, *self.supports_128bit_integers.lock().expect("lock"))
	}

	fn target_machine_factory(&self, _sess: &Session, _opt_level: OptLevel, _features: &[String]) -> TargetMachineFactoryFn<Self> {
	// TODO(antoyo): set opt level.
	Arc::new(\|_\| {
	Ok(())
	})
	}
	}

	pub struct ModuleBuffer;

	impl ModuleBufferMethods for ModuleBuffer {
	fn data(&self) -> &[u8] {
	unimplemented!();
	}
	}

	pub struct ThinBuffer;

	impl ThinBufferMethods for ThinBuffer {
	fn data(&self) -> &[u8] {
	unimplemented!();
	}
	}

	pub struct GccContext {
	context: Context<'static>,
	}

	unsafe impl Send for GccContext {}
	// FIXME(antoyo): that shouldn't be Sync. Parallel compilation is currently disabled with "-Zno-parallel-llvm". Try to disable it here.
	unsafe impl Sync for GccContext {}

	impl WriteBackendMethods for GccCodegenBackend {
	type Module = GccContext;
	type TargetMachine = ();
	type ModuleBuffer = ModuleBuffer;
	type ThinData = ();
	type ThinBuffer = ThinBuffer;

	fn run_fat_lto(_cgcx: &CodegenContext<Self>, mut modules: Vec<FatLTOInput<Self>>, _cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>) -> Result<LtoModuleCodegen<Self>, FatalError> {
	// TODO(antoyo): implement LTO by sending -flto to libgccjit and adding the appropriate gcc linker plugins.
	// NOTE: implemented elsewhere.
	// TODO(antoyo): what is implemented elsewhere ^ ?
	let module =
	match modules.remove(0) {
	FatLTOInput::InMemory(module) => module,
	FatLTOInput::Serialized { .. } => {
	unimplemented!();
	}
	};
	Ok(LtoModuleCodegen::Fat { module, _serialized_bitcode: vec![] })
	}

	fn run_thin_lto(_cgcx: &CodegenContext<Self>, _modules: Vec<(String, Self::ThinBuffer)>, _cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>) -> Result<(Vec<LtoModuleCodegen<Self>>, Vec<WorkProduct>), FatalError> {
	unimplemented!();
	}

	fn print_pass_timings(&self) {
	unimplemented!();
	}

	unsafe fn optimize(_cgcx: &CodegenContext<Self>, _diag_handler: &Handler, module: &ModuleCodegen<Self::Module>, config: &ModuleConfig) -> Result<(), FatalError> {
	module.module_llvm.context.set_optimization_level(to_gcc_opt_level(config.opt_level));
	Ok(())
	}

	fn optimize_fat(_cgcx: &CodegenContext<Self>, _module: &mut ModuleCodegen<Self::Module>) -> Result<(), FatalError> {
	// TODO(antoyo)
	Ok(())
	}

	unsafe fn optimize_thin(_cgcx: &CodegenContext<Self>, _thin: ThinModule<Self>) -> Result<ModuleCodegen<Self::Module>, FatalError> {
	unimplemented!();
	}

	unsafe fn codegen(cgcx: &CodegenContext<Self>, diag_handler: &Handler, module: ModuleCodegen<Self::Module>, config: &ModuleConfig) -> Result<CompiledModule, FatalError> {
	back::write::codegen(cgcx, diag_handler, module, config)
	}

	fn prepare_thin(_module: ModuleCodegen<Self::Module>) -> (String, Self::ThinBuffer) {
	unimplemented!();
	}

	fn serialize_module(_module: ModuleCodegen<Self::Module>) -> (String, Self::ModuleBuffer) {
	unimplemented!();
	}

	fn run_link(cgcx: &CodegenContext<Self>, diag_handler: &Handler, modules: Vec<ModuleCodegen<Self::Module>>) -> Result<ModuleCodegen<Self::Module>, FatalError> {
	back::write::link(cgcx, diag_handler, modules)
	}
	}

	/// This is the entrypoint for a hot plugged rustc_codegen_gccjit
	#[no_mangle]
	pub fn __rustc_codegen_backend() -> Box<dyn CodegenBackend> {
	Box::new(GccCodegenBackend {
	supports_128bit_integers: Arc::new(Mutex::new(false)),
	})
	}

	fn to_gcc_opt_level(optlevel: Option<OptLevel>) -> OptimizationLevel {
	match optlevel {
	None => OptimizationLevel::None,
	Some(level) => {
	match level {
	OptLevel::No => OptimizationLevel::None,
	OptLevel::Less => OptimizationLevel::Limited,
	OptLevel::Default => OptimizationLevel::Standard,
	OptLevel::Aggressive => OptimizationLevel::Aggressive,
	OptLevel::Size \| OptLevel::SizeMin => OptimizationLevel::Limited,
	}
	},
	}
	}

	fn handle_native(name: &str) -> &str {
	if name != "native" {
	return name;
	}

	unimplemented!();
	}

	pub fn target_cpu(sess: &Session) -> &str {
	match sess.opts.cg.target_cpu {
	Some(ref name) => handle_native(name),
	None => handle_native(sess.target.cpu.as_ref()),
	}
	}

	pub fn target_features(sess: &Session, allow_unstable: bool) -> Vec<Symbol> {
	supported_target_features(sess)
	.iter()
	.filter_map(
	\|&(feature, gate)\| {
	if sess.is_nightly_build() \|\| allow_unstable \|\| gate.is_none() { Some(feature) } else { None }
	},
	)
	.filter(\|_feature\| {
	// TODO(antoyo): implement a way to get enabled feature in libgccjit.
	// Probably using the equivalent of __builtin_cpu_supports.
	#[cfg(feature="master")]
	{
	_feature.contains("sse") \|\| _feature.contains("avx")
	}
	#[cfg(not(feature="master"))]
	{
	false
	}
	/*
	adx, aes, avx, avx2, avx512bf16, avx512bitalg, avx512bw, avx512cd, avx512dq, avx512er, avx512f, avx512gfni,
	avx512ifma, avx512pf, avx512vaes, avx512vbmi, avx512vbmi2, avx512vl, avx512vnni, avx512vp2intersect, avx512vpclmulqdq,
	avx512vpopcntdq, bmi1, bmi2, cmpxchg16b, ermsb, f16c, fma, fxsr, lzcnt, movbe, pclmulqdq, popcnt, rdrand, rdseed, rtm,
	sha, sse, sse2, sse3, sse4.1, sse4.2, sse4a, ssse3, tbm, xsave, xsavec, xsaveopt, xsaves
	*/
	//false
	})
	.map(\|feature\| Symbol::intern(feature))
	.collect()
	}