Auto merge of rust-lang#105252 - bjorn3:codegen_less_pair_values, r=nagisa

Use struct types during codegen in less places

This makes it easier to use cg_ssa from a backend like Cranelift that doesn't have any struct types at all. After this PR struct types are still used for function arguments and return values. Removing those usages is harder but should still be doable.

Author: bors

compiler/rustc_codegen_gcc/src/builder.rs

@@ -1119,18 +1119,18 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
         // TODO(antoyo)
     }
 
-    fn cleanup_landing_pad(&mut self, _ty: Type<'gcc>, _pers_fn: RValue<'gcc>) -> RValue<'gcc> {
-        let field1 = self.context.new_field(None, self.u8_type.make_pointer(), "landing_pad_field_1");
-        let field2 = self.context.new_field(None, self.i32_type, "landing_pad_field_1");
-        let struct_type = self.context.new_struct_type(None, "landing_pad", &[field1, field2]);
-        self.current_func().new_local(None, struct_type.as_type(), "landing_pad")
-            .to_rvalue()
+    fn cleanup_landing_pad(&mut self, _pers_fn: RValue<'gcc>) -> (RValue<'gcc>, RValue<'gcc>) {
+        (
+            self.current_func().new_local(None, self.u8_type.make_pointer(), "landing_pad0")
+                .to_rvalue(),
+            self.current_func().new_local(None, self.i32_type, "landing_pad1").to_rvalue(),
+        )
         // TODO(antoyo): Properly implement unwinding.
         // the above is just to make the compilation work as it seems
         // rustc_codegen_ssa now calls the unwinding builder methods even on panic=abort.
     }
 
-    fn resume(&mut self, _exn: RValue<'gcc>) {
+    fn resume(&mut self, _exn0: RValue<'gcc>, _exn1: RValue<'gcc>) {
         // TODO(bjorn3): Properly implement unwinding.
         self.unreachable();
     }

compiler/rustc_codegen_llvm/src/builder.rs

@@ -979,15 +979,20 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         }
     }
 
-    fn cleanup_landing_pad(&mut self, ty: &'ll Type, pers_fn: &'ll Value) -> &'ll Value {
+    fn cleanup_landing_pad(&mut self, pers_fn: &'ll Value) -> (&'ll Value, &'ll Value) {
+        let ty = self.type_struct(&[self.type_i8p(), self.type_i32()], false);
         let landing_pad = self.landing_pad(ty, pers_fn, 1 /* FIXME should this be 0? */);
         unsafe {
             llvm::LLVMSetCleanup(landing_pad, llvm::True);
         }
-        landing_pad
+        (self.extract_value(landing_pad, 0), self.extract_value(landing_pad, 1))
     }
 
-    fn resume(&mut self, exn: &'ll Value) {
+    fn resume(&mut self, exn0: &'ll Value, exn1: &'ll Value) {
+        let ty = self.type_struct(&[self.type_i8p(), self.type_i32()], false);
+        let mut exn = self.const_undef(ty);
+        exn = self.insert_value(exn, exn0, 0);
+        exn = self.insert_value(exn, exn1, 1);
         unsafe {
             llvm::LLVMBuildResume(self.llbuilder, exn);
         }

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -424,7 +424,9 @@ impl<'ll, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'_, 'll, 'tcx> {
         typeid: &'ll Value,
     ) -> Self::Value {
         let vtable_byte_offset = self.const_i32(vtable_byte_offset as i32);
-        self.call_intrinsic("llvm.type.checked.load", &[llvtable, vtable_byte_offset, typeid])
+        let type_checked_load =
+            self.call_intrinsic("llvm.type.checked.load", &[llvtable, vtable_byte_offset, typeid]);
+        self.extract_value(type_checked_load, 0)
     }
 
     fn va_start(&mut self, va_list: &'ll Value) -> &'ll Value {

compiler/rustc_codegen_ssa/src/meth.rs

@@ -31,8 +31,7 @@ impl<'a, 'tcx> VirtualIndex {
             let typeid =
                 bx.typeid_metadata(typeid_for_trait_ref(bx.tcx(), expect_dyn_trait_in_self(ty)));
             let vtable_byte_offset = self.0 * bx.data_layout().pointer_size.bytes();
-            let type_checked_load = bx.type_checked_load(llvtable, vtable_byte_offset, typeid);
-            let func = bx.extract_value(type_checked_load, 0);
+            let func = bx.type_checked_load(llvtable, vtable_byte_offset, typeid);
             bx.pointercast(func, llty)
         } else {
             let ptr_align = bx.tcx().data_layout.pointer_align.abi;

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -289,16 +289,13 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             bx.cleanup_ret(funclet, None);
         } else {
             let slot = self.get_personality_slot(bx);
-            let lp0 = slot.project_field(bx, 0);
-            let lp0 = bx.load_operand(lp0).immediate();
-            let lp1 = slot.project_field(bx, 1);
-            let lp1 = bx.load_operand(lp1).immediate();
+            let exn0 = slot.project_field(bx, 0);
+            let exn0 = bx.load_operand(exn0).immediate();
+            let exn1 = slot.project_field(bx, 1);
+            let exn1 = bx.load_operand(exn1).immediate();
             slot.storage_dead(bx);
 
-            let mut lp = bx.const_undef(self.landing_pad_type());
-            lp = bx.insert_value(lp, lp0, 0);
-            lp = bx.insert_value(lp, lp1, 1);
-            bx.resume(lp);
+            bx.resume(exn0, exn1);
         }
     }
 
@@ -1636,24 +1633,17 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             let mut cleanup_bx = Bx::build(self.cx, cleanup_llbb);
 
             let llpersonality = self.cx.eh_personality();
-            let llretty = self.landing_pad_type();
-            let lp = cleanup_bx.cleanup_landing_pad(llretty, llpersonality);
+            let (exn0, exn1) = cleanup_bx.cleanup_landing_pad(llpersonality);
 
             let slot = self.get_personality_slot(&mut cleanup_bx);
             slot.storage_live(&mut cleanup_bx);
-            Pair(cleanup_bx.extract_value(lp, 0), cleanup_bx.extract_value(lp, 1))
-                .store(&mut cleanup_bx, slot);
+            Pair(exn0, exn1).store(&mut cleanup_bx, slot);
 
             cleanup_bx.br(llbb);
             cleanup_llbb
         }
     }
 
-    fn landing_pad_type(&self) -> Bx::Type {
-        let cx = self.cx;
-        cx.type_struct(&[cx.type_i8p(), cx.type_i32()], false)
-    }
-
     fn unreachable_block(&mut self) -> Bx::BasicBlock {
         self.unreachable_block.unwrap_or_else(|| {
             let llbb = Bx::append_block(self.cx, self.llfn, "unreachable");
@@ -1673,8 +1663,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             self.set_debug_loc(&mut bx, mir::SourceInfo::outermost(self.mir.span));
 
             let llpersonality = self.cx.eh_personality();
-            let llretty = self.landing_pad_type();
-            bx.cleanup_landing_pad(llretty, llpersonality);
+            bx.cleanup_landing_pad(llpersonality);
 
             let (fn_abi, fn_ptr) = common::build_langcall(&bx, None, LangItem::PanicNoUnwind);
             let fn_ty = bx.fn_decl_backend_type(&fn_abi);

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

@@ -462,7 +462,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 assert!(bx.cx().tcx().is_static(def_id));
                 let static_ = bx.get_static(def_id);
                 let layout = bx.layout_of(bx.cx().tcx().static_ptr_ty(def_id));
-                OperandRef::from_immediate_or_packed_pair(bx, static_, layout)
+                OperandRef { val: OperandValue::Immediate(static_), layout }
             }
             mir::Rvalue::Use(ref operand) => self.codegen_operand(bx, operand),
             mir::Rvalue::Repeat(..) | mir::Rvalue::Aggregate(..) => {

compiler/rustc_codegen_ssa/src/traits/builder.rs

@@ -271,8 +271,8 @@ pub trait BuilderMethods<'a, 'tcx>:
     fn set_personality_fn(&mut self, personality: Self::Value);
 
     // These are used by everyone except msvc
-    fn cleanup_landing_pad(&mut self, ty: Self::Type, pers_fn: Self::Value) -> Self::Value;
-    fn resume(&mut self, exn: Self::Value);
+    fn cleanup_landing_pad(&mut self, pers_fn: Self::Value) -> (Self::Value, Self::Value);
+    fn resume(&mut self, exn0: Self::Value, exn1: Self::Value);
 
     // These are used only by msvc
     fn cleanup_pad(&mut self, parent: Option<Self::Value>, args: &[Self::Value]) -> Self::Funclet;