rustc_codegen_ssa: take a FnAbi instead of a FnSig in declare_fn.

Author: eddyb

src/librustc_codegen_llvm/attributes.rs

@@ -6,7 +6,7 @@ use rustc::hir::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::session::Session;
 use rustc::session::config::{Sanitizer, OptLevel};
-use rustc::ty::{self, TyCtxt, PolyFnSig};
+use rustc::ty::TyCtxt;
 use rustc::ty::layout::HasTyCtxt;
 use rustc::ty::query::Providers;
 use rustc_data_structures::small_c_str::SmallCStr;
@@ -203,7 +203,7 @@ pub fn from_fn_attrs(
     cx: &CodegenCx<'ll, 'tcx>,
     llfn: &'ll Value,
     id: Option<DefId>,
-    sig: PolyFnSig<'tcx>,
+    abi: Abi,
 ) {
     let codegen_fn_attrs = id.map(|id| cx.tcx.codegen_fn_attrs(id))
         .unwrap_or_else(|| CodegenFnAttrs::new());
@@ -276,8 +276,7 @@ pub fn from_fn_attrs(
         // Special attribute for allocator functions, which can't unwind.
         false
     } else {
-        let sig = cx.tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
-        if sig.abi == Abi::Rust || sig.abi == Abi::RustCall {
+        if abi == Abi::Rust || abi == Abi::RustCall {
             // Any Rust method (or `extern "Rust" fn` or `extern
             // "rust-call" fn`) is explicitly allowed to unwind
             // (unless it has no-unwind attribute, handled above).

src/librustc_codegen_llvm/callee.rs

@@ -4,14 +4,15 @@
 //! and methods are represented as just a fn ptr and not a full
 //! closure.
 
+use crate::abi::FnAbi;
 use crate::attributes;
 use crate::llvm;
 use crate::context::CodegenCx;
 use crate::value::Value;
 use rustc_codegen_ssa::traits::*;
 
-use rustc::ty::{TypeFoldable, Instance};
-use rustc::ty::layout::{LayoutOf, HasTyCtxt};
+use rustc::ty::{self, TypeFoldable, Instance};
+use rustc::ty::layout::{FnAbiExt, LayoutOf, HasTyCtxt};
 
 /// Codegens a reference to a fn/method item, monomorphizing and
 /// inlining as it goes.
@@ -32,19 +33,19 @@ pub fn get_fn(
     assert!(!instance.substs.has_escaping_bound_vars());
     assert!(!instance.substs.has_param_types());
 
-    let sig = instance.fn_sig(cx.tcx());
     if let Some(&llfn) = cx.instances.borrow().get(&instance) {
         return llfn;
     }
 
+    let sig = instance.fn_sig(cx.tcx());
     let sym = tcx.symbol_name(instance).name.as_str();
     debug!("get_fn({:?}: {:?}) => {}", instance, sig, sym);
 
-    // Create a fn pointer with the substituted signature.
-    let fn_ptr_ty = tcx.mk_fn_ptr(sig);
-    let llptrty = cx.backend_type(cx.layout_of(fn_ptr_ty));
-
     let llfn = if let Some(llfn) = cx.get_declared_value(&sym) {
+        // Create a fn pointer with the substituted signature.
+        let fn_ptr_ty = tcx.mk_fn_ptr(sig);
+        let llptrty = cx.backend_type(cx.layout_of(fn_ptr_ty));
+
         // This is subtle and surprising, but sometimes we have to bitcast
         // the resulting fn pointer.  The reason has to do with external
         // functions.  If you have two crates that both bind the same C
@@ -76,14 +77,15 @@ pub fn get_fn(
             llfn
         }
     } else {
-        let llfn = cx.declare_fn(&sym, sig);
-        assert_eq!(cx.val_ty(llfn), llptrty);
+        let sig = tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
+        let fn_abi = FnAbi::new(cx, sig, &[]);
+        let llfn = cx.declare_fn(&sym, &fn_abi);
         debug!("get_fn: not casting pointer!");
 
         if instance.def.is_inline(tcx) {
             attributes::inline(cx, llfn, attributes::InlineAttr::Hint);
         }
-        attributes::from_fn_attrs(cx, llfn, Some(instance.def.def_id()), sig);
+        attributes::from_fn_attrs(cx, llfn, Some(instance.def.def_id()), sig.abi);
 
         let instance_def_id = instance.def_id();
 

src/librustc_codegen_llvm/context.rs

@@ -1,3 +1,4 @@
+use crate::abi::FnAbi;
 use crate::attributes;
 use crate::llvm;
 use crate::llvm_util;
@@ -15,7 +16,7 @@ use rustc::mir::mono::CodegenUnit;
 use rustc::session::config::{self, DebugInfo};
 use rustc::session::Session;
 use rustc::ty::layout::{
-    LayoutError, LayoutOf, PointeeInfo, Size, TyLayout, VariantIdx, HasParamEnv
+    FnAbiExt, LayoutError, LayoutOf, PointeeInfo, Size, TyLayout, VariantIdx, HasParamEnv
 };
 use rustc::ty::{self, Ty, TyCtxt, Instance};
 use rustc::util::nodemap::FxHashMap;
@@ -412,15 +413,16 @@ impl MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             return llfn;
         }
 
-        let sig = ty::Binder::bind(tcx.mk_fn_sig(
+        let sig = tcx.mk_fn_sig(
             iter::once(tcx.mk_mut_ptr(tcx.types.u8)),
             tcx.types.never,
             false,
             hir::Unsafety::Unsafe,
             Abi::C
-        ));
+        );
 
-        let llfn = self.declare_fn("rust_eh_unwind_resume", sig);
+        let fn_abi = FnAbi::new(self, sig, &[]);
+        let llfn = self.declare_fn("rust_eh_unwind_resume", &fn_abi);
         attributes::apply_target_cpu_attr(self, llfn);
         unwresume.set(Some(llfn));
         llfn

src/librustc_codegen_llvm/declare.rs

@@ -18,8 +18,7 @@ use crate::attributes;
 use crate::context::CodegenCx;
 use crate::type_::Type;
 use crate::value::Value;
-use rustc::ty::{self, PolyFnSig};
-use rustc::ty::layout::{FnAbiExt, LayoutOf};
+use rustc::ty::Ty;
 use rustc::session::config::Sanitizer;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_codegen_ssa::traits::*;
@@ -94,16 +93,14 @@ impl DeclareMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     fn declare_fn(
         &self,
         name: &str,
-        sig: PolyFnSig<'tcx>,
+        fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
     ) -> &'ll Value {
-        debug!("declare_rust_fn(name={:?}, sig={:?})", name, sig);
-        let sig = self.tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
-        debug!("declare_rust_fn (after region erasure) sig={:?}", sig);
+        debug!("declare_rust_fn(name={:?}, fn_abi={:?})", name, fn_abi);
 
-        let fn_abi = FnAbi::new(self, sig, &[]);
         let llfn = declare_raw_fn(self, name, fn_abi.llvm_cconv(), fn_abi.llvm_type(self));
 
-        if self.layout_of(sig.output()).abi.is_uninhabited() {
+        // FIXME(eddyb) move into `FnAbi::apply_attrs_llfn`.
+        if fn_abi.ret.layout.abi.is_uninhabited() {
             llvm::Attribute::NoReturn.apply_llfn(Function, llfn);
         }
 

src/librustc_codegen_llvm/intrinsic.rs

@@ -1,4 +1,3 @@
-use crate::attributes;
 use crate::llvm;
 use crate::llvm_util;
 use crate::abi::{Abi, FnAbi, LlvmType, PassMode};
@@ -14,7 +13,7 @@ use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
 use rustc_codegen_ssa::glue;
 use rustc_codegen_ssa::base::{to_immediate, wants_msvc_seh, compare_simd_types};
 use rustc::ty::{self, Ty};
-use rustc::ty::layout::{self, LayoutOf, HasTyCtxt, Primitive};
+use rustc::ty::layout::{self, FnAbiExt, LayoutOf, HasTyCtxt, Primitive};
 use rustc::mir::interpret::GlobalId;
 use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
 use rustc::hir;
@@ -1006,17 +1005,17 @@ fn gen_fn<'ll, 'tcx>(
     output: Ty<'tcx>,
     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
 ) -> &'ll Value {
-    let rust_fn_sig = ty::Binder::bind(cx.tcx.mk_fn_sig(
+    let rust_fn_sig = cx.tcx.mk_fn_sig(
         inputs.into_iter(),
         output,
         false,
         hir::Unsafety::Unsafe,
         Abi::Rust
-    ));
-    let llfn = cx.declare_fn(name, rust_fn_sig);
+    );
+    let fn_abi = FnAbi::new(cx, rust_fn_sig, &[]);
+    let llfn = cx.declare_fn(name, &fn_abi);
     // FIXME(eddyb) find a nicer way to do this.
     unsafe { llvm::LLVMRustSetLinkage(llfn, llvm::Linkage::InternalLinkage) };
-    attributes::from_fn_attrs(cx, llfn, None, rust_fn_sig);
     let bx = Builder::new_block(cx, llfn, "entry-block");
     codegen(bx);
     llfn

src/librustc_codegen_llvm/mono_item.rs

@@ -1,12 +1,13 @@
+use crate::abi::FnAbi;
 use crate::attributes;
 use crate::base;
 use crate::context::CodegenCx;
 use crate::llvm;
 use crate::type_of::LayoutLlvmExt;
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::mir::mono::{Linkage, Visibility};
-use rustc::ty::{TypeFoldable, Instance};
-use rustc::ty::layout::{LayoutOf, HasTyCtxt};
+use rustc::ty::{self, TypeFoldable, Instance};
+use rustc::ty::layout::{FnAbiExt, LayoutOf, HasTyCtxt};
 use rustc_codegen_ssa::traits::*;
 
 pub use rustc::mir::mono::MonoItem;
@@ -43,9 +44,14 @@ impl PreDefineMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                 !instance.substs.has_param_types());
 
         let mono_sig = instance.fn_sig(self.tcx());
-        let attrs = self.tcx.codegen_fn_attrs(instance.def_id());
-        let lldecl = self.declare_fn(symbol_name, mono_sig);
+        let mono_sig = self.tcx().normalize_erasing_late_bound_regions(
+            ty::ParamEnv::reveal_all(),
+            &mono_sig,
+        );
+        let fn_abi = FnAbi::new(self, mono_sig, &[]);
+        let lldecl = self.declare_fn(symbol_name, &fn_abi);
         unsafe { llvm::LLVMRustSetLinkage(lldecl, base::linkage_to_llvm(linkage)) };
+        let attrs = self.tcx.codegen_fn_attrs(instance.def_id());
         base::set_link_section(lldecl, &attrs);
         if linkage == Linkage::LinkOnceODR ||
             linkage == Linkage::WeakODR {
@@ -75,7 +81,7 @@ impl PreDefineMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             self,
             lldecl,
             Some(instance.def.def_id()),
-            mono_sig,
+            mono_sig.abi,
         );
 
         self.instances.borrow_mut().insert(instance, lldecl);

src/librustc_codegen_ssa/traits/declare.rs

@@ -1,7 +1,8 @@
 use super::BackendTypes;
 use rustc::hir::def_id::DefId;
 use rustc::mir::mono::{Linkage, Visibility};
-use rustc::ty::{self, Instance};
+use rustc::ty::{Instance, Ty};
+use rustc_target::abi::call::FnAbi;
 
 pub trait DeclareMethods<'tcx>: BackendTypes {
     /// Declare a global value.
@@ -23,7 +24,7 @@ pub trait DeclareMethods<'tcx>: BackendTypes {
     ///
     /// If there’s a value with the same name already declared, the function will
     /// update the declaration and return existing Value instead.
-    fn declare_fn(&self, name: &str, sig: ty::PolyFnSig<'tcx>) -> Self::Function;
+    fn declare_fn(&self, name: &str, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> Self::Function;
 
     /// Declare a global with an intention to define it.
     ///