diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src/allocator.rs')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/allocator.rs | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_llvm/src/allocator.rs b/compiler/rustc_codegen_llvm/src/allocator.rs new file mode 100644 index 00000000000..ca376029735 --- /dev/null +++ b/compiler/rustc_codegen_llvm/src/allocator.rs @@ -0,0 +1,176 @@ +use crate::attributes; +use libc::c_uint; +use rustc_ast::expand::allocator::{ + alloc_error_handler_name, default_fn_name, global_fn_name, AllocatorKind, AllocatorTy, + ALLOCATOR_METHODS, NO_ALLOC_SHIM_IS_UNSTABLE, +}; +use rustc_middle::bug; +use rustc_middle::ty::TyCtxt; +use rustc_session::config::{DebugInfo, OomStrategy}; + +use crate::debuginfo; +use crate::llvm::{self, Context, False, Module, True, Type}; +use crate::ModuleLlvm; + +pub(crate) unsafe fn codegen( + tcx: TyCtxt<'_>, + module_llvm: &mut ModuleLlvm, + module_name: &str, + kind: AllocatorKind, + alloc_error_handler_kind: AllocatorKind, +) { + let llcx = &*module_llvm.llcx; + let llmod = module_llvm.llmod(); + let usize = match tcx.sess.target.pointer_width { + 16 => llvm::LLVMInt16TypeInContext(llcx), + 32 => llvm::LLVMInt32TypeInContext(llcx), + 64 => llvm::LLVMInt64TypeInContext(llcx), + tws => bug!("Unsupported target word size for int: {}", tws), + }; + let i8 = llvm::LLVMInt8TypeInContext(llcx); + let i8p = llvm::LLVMPointerTypeInContext(llcx, 0); + + if kind == AllocatorKind::Default { + for method in ALLOCATOR_METHODS { + let mut args = Vec::with_capacity(method.inputs.len()); + for input in method.inputs.iter() { + match input.ty { + AllocatorTy::Layout => { + args.push(usize); // size + args.push(usize); // align + } + AllocatorTy::Ptr => args.push(i8p), + AllocatorTy::Usize => args.push(usize), + + AllocatorTy::ResultPtr | AllocatorTy::Unit => panic!("invalid allocator arg"), + } + } + let output = match method.output { + AllocatorTy::ResultPtr => Some(i8p), + AllocatorTy::Unit => None, + + AllocatorTy::Layout | AllocatorTy::Usize | AllocatorTy::Ptr => { + panic!("invalid allocator output") + } + }; + + let from_name = global_fn_name(method.name); + let to_name = default_fn_name(method.name); + + create_wrapper_function(tcx, llcx, llmod, &from_name, &to_name, &args, output, false); + } + } + + // rust alloc error handler + create_wrapper_function( + tcx, + llcx, + llmod, + "__rust_alloc_error_handler", + alloc_error_handler_name(alloc_error_handler_kind), + &[usize, usize], // size, align + None, + true, + ); + + // __rust_alloc_error_handler_should_panic + let name = OomStrategy::SYMBOL; + let ll_g = llvm::LLVMRustGetOrInsertGlobal(llmod, name.as_ptr().cast(), name.len(), i8); + if tcx.sess.default_hidden_visibility() { + llvm::LLVMRustSetVisibility(ll_g, llvm::Visibility::Hidden); + } + let val = tcx.sess.opts.unstable_opts.oom.should_panic(); + let llval = llvm::LLVMConstInt(i8, val as u64, False); + llvm::LLVMSetInitializer(ll_g, llval); + + let name = NO_ALLOC_SHIM_IS_UNSTABLE; + let ll_g = llvm::LLVMRustGetOrInsertGlobal(llmod, name.as_ptr().cast(), name.len(), i8); + if tcx.sess.default_hidden_visibility() { + llvm::LLVMRustSetVisibility(ll_g, llvm::Visibility::Hidden); + } + let llval = llvm::LLVMConstInt(i8, 0, False); + llvm::LLVMSetInitializer(ll_g, llval); + + if tcx.sess.opts.debuginfo != DebugInfo::None { + let dbg_cx = debuginfo::CodegenUnitDebugContext::new(llmod); + debuginfo::metadata::build_compile_unit_di_node(tcx, module_name, &dbg_cx); + dbg_cx.finalize(tcx.sess); + } +} + +fn create_wrapper_function( + tcx: TyCtxt<'_>, + llcx: &Context, + llmod: &Module, + from_name: &str, + to_name: &str, + args: &[&Type], + output: Option<&Type>, + no_return: bool, +) { + unsafe { + let ty = llvm::LLVMFunctionType( + output.unwrap_or_else(|| llvm::LLVMVoidTypeInContext(llcx)), + args.as_ptr(), + args.len() as c_uint, + False, + ); + let llfn = llvm::LLVMRustGetOrInsertFunction( + llmod, + from_name.as_ptr().cast(), + from_name.len(), + ty, + ); + let no_return = if no_return { + // -> ! DIFlagNoReturn + let no_return = llvm::AttributeKind::NoReturn.create_attr(llcx); + attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[no_return]); + Some(no_return) + } else { + None + }; + + if tcx.sess.default_hidden_visibility() { + llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden); + } + if tcx.sess.must_emit_unwind_tables() { + let uwtable = + attributes::uwtable_attr(llcx, tcx.sess.opts.unstable_opts.use_sync_unwind); + attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[uwtable]); + } + + let callee = + llvm::LLVMRustGetOrInsertFunction(llmod, to_name.as_ptr().cast(), to_name.len(), ty); + if let Some(no_return) = no_return { + // -> ! DIFlagNoReturn + attributes::apply_to_llfn(callee, llvm::AttributePlace::Function, &[no_return]); + } + llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden); + + let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, c"entry".as_ptr().cast()); + + let llbuilder = llvm::LLVMCreateBuilderInContext(llcx); + llvm::LLVMPositionBuilderAtEnd(llbuilder, llbb); + let args = args + .iter() + .enumerate() + .map(|(i, _)| llvm::LLVMGetParam(llfn, i as c_uint)) + .collect::<Vec<_>>(); + let ret = llvm::LLVMRustBuildCall( + llbuilder, + ty, + callee, + args.as_ptr(), + args.len() as c_uint, + [].as_ptr(), + 0 as c_uint, + ); + llvm::LLVMSetTailCall(ret, True); + if output.is_some() { + llvm::LLVMBuildRet(llbuilder, ret); + } else { + llvm::LLVMBuildRetVoid(llbuilder); + } + llvm::LLVMDisposeBuilder(llbuilder); + } +} |