Remove most trap functions and remove all trapnz usages

Author: bjorn3

src/base.rs

@@ -90,7 +90,8 @@ pub(crate) fn codegen_fn<'tcx>(
     if !crate::constant::check_constants(&mut fx) {
         fx.bcx.append_block_params_for_function_params(fx.block_map[START_BLOCK]);
         fx.bcx.switch_to_block(fx.block_map[START_BLOCK]);
-        crate::trap::trap_unreachable(&mut fx, "compilation should have been aborted");
+        // compilation should have been aborted
+        fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
     } else if arg_uninhabited {
         fx.bcx.append_block_params_for_function_params(fx.block_map[START_BLOCK]);
         fx.bcx.switch_to_block(fx.block_map[START_BLOCK]);
@@ -457,17 +458,8 @@ fn codegen_fn_content(fx: &mut FunctionCx<'_, '_, '_>) {
                     template,
                     operands,
                     *options,
+                    *destination,
                 );
-
-                match *destination {
-                    Some(destination) => {
-                        let destination_block = fx.get_block(destination);
-                        fx.bcx.ins().jump(destination_block, &[]);
-                    }
-                    None => {
-                        fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
-                    }
-                }
             }
             TerminatorKind::Resume | TerminatorKind::Abort => {
                 // FIXME implement unwinding
@@ -711,9 +703,7 @@ fn codegen_stmt<'tcx>(
                 Rvalue::Discriminant(place) => {
                     let place = codegen_place(fx, place);
                     let value = place.to_cvalue(fx);
-                    let discr =
-                        crate::discriminant::codegen_get_discriminant(fx, value, dest_layout);
-                    lval.write_cvalue(fx, discr);
+                    crate::discriminant::codegen_get_discriminant(fx, lval, value, dest_layout);
                 }
                 Rvalue::Repeat(ref operand, times) => {
                     let operand = codegen_operand(fx, operand);

src/discriminant.rs

@@ -62,16 +62,14 @@ pub(crate) fn codegen_set_discriminant<'tcx>(
 
 pub(crate) fn codegen_get_discriminant<'tcx>(
     fx: &mut FunctionCx<'_, '_, 'tcx>,
+    dest: CPlace<'tcx>,
     value: CValue<'tcx>,
     dest_layout: TyAndLayout<'tcx>,
-) -> CValue<'tcx> {
+) {
     let layout = value.layout();
 
-    if layout.abi == Abi::Uninhabited {
-        let true_ = fx.bcx.ins().iconst(types::I32, 1);
-        fx.bcx.ins().trapnz(true_, TrapCode::UnreachableCodeReached);
-        // Return a dummy value
-        return CValue::by_ref(Pointer::const_addr(fx, 0), dest_layout);
+    if layout.abi.is_uninhabited() {
+        return;
     }
 
     let (tag_scalar, tag_field, tag_encoding) = match &layout.variants {
@@ -89,7 +87,9 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
             } else {
                 ty::ScalarInt::try_from_uint(discr_val, dest_layout.size).unwrap()
             };
-            return CValue::const_val(fx, dest_layout, discr_val);
+            let res = CValue::const_val(fx, dest_layout, discr_val);
+            dest.write_cvalue(fx, res);
+            return;
         }
         Variants::Multiple { tag, tag_field, tag_encoding, variants: _ } => {
             (tag, *tag_field, tag_encoding)
@@ -110,7 +110,8 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
                 _ => false,
             };
             let val = clif_intcast(fx, tag, cast_to, signed);
-            CValue::by_val(val, dest_layout)
+            let res = CValue::by_val(val, dest_layout);
+            dest.write_cvalue(fx, res);
         }
         TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start } => {
             // Rebase from niche values to discriminants, and check
@@ -170,7 +171,8 @@ pub(crate) fn codegen_get_discriminant<'tcx>(
 
             let dataful_variant = fx.bcx.ins().iconst(cast_to, i64::from(dataful_variant.as_u32()));
             let discr = fx.bcx.ins().select(is_niche, niche_discr, dataful_variant);
-            CValue::by_val(discr, dest_layout)
+            let res = CValue::by_val(discr, dest_layout);
+            dest.write_cvalue(fx, res);
         }
     }
 }

src/inline_asm.rs

@@ -15,13 +15,13 @@ pub(crate) fn codegen_inline_asm<'tcx>(
     template: &[InlineAsmTemplatePiece],
     operands: &[InlineAsmOperand<'tcx>],
     options: InlineAsmOptions,
+    destination: Option<mir::BasicBlock>,
 ) {
     // FIXME add .eh_frame unwind info directives
 
     if !template.is_empty() {
         if template[0] == InlineAsmTemplatePiece::String("int $$0x29".to_string()) {
-            let true_ = fx.bcx.ins().iconst(types::I32, 1);
-            fx.bcx.ins().trapnz(true_, TrapCode::User(1));
+            fx.bcx.ins().trap(TrapCode::User(1));
             return;
         } else if template[0] == InlineAsmTemplatePiece::String("movq %rbx, ".to_string())
             && matches!(
@@ -101,12 +101,16 @@ pub(crate) fn codegen_inline_asm<'tcx>(
             ebx_place.write_cvalue(fx, CValue::by_val(ebx, fx.layout_of(fx.tcx.types.u32)));
             ecx_place.write_cvalue(fx, CValue::by_val(ecx, fx.layout_of(fx.tcx.types.u32)));
             edx_place.write_cvalue(fx, CValue::by_val(edx, fx.layout_of(fx.tcx.types.u32)));
+            let destination_block = fx.get_block(destination.unwrap());
+            fx.bcx.ins().jump(destination_block, &[]);
             return;
         } else if fx.tcx.symbol_name(fx.instance).name.starts_with("___chkstk") {
             // ___chkstk, ___chkstk_ms and __alloca are only used on Windows
             crate::trap::trap_unimplemented(fx, "Stack probes are not supported");
+            return;
         } else if fx.tcx.symbol_name(fx.instance).name == "__alloca" {
             crate::trap::trap_unimplemented(fx, "Alloca is not supported");
+            return;
         }
     }
 
@@ -175,6 +179,16 @@ pub(crate) fn codegen_inline_asm<'tcx>(
     }
 
     call_inline_asm(fx, &asm_name, asm_gen.stack_slot_size, inputs, outputs);
+
+    match destination {
+        Some(destination) => {
+            let destination_block = fx.get_block(destination);
+            fx.bcx.ins().jump(destination_block, &[]);
+        }
+        None => {
+            fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
+        }
+    }
 }
 
 struct InlineAssemblyGenerator<'a, 'tcx> {

src/intrinsics/cpuid.rs

@@ -62,7 +62,7 @@ pub(crate) fn codegen_cpuid_call<'tcx>(
     fx.bcx.ins().jump(dest, &[zero, zero, proc_info_ecx, proc_info_edx]);
 
     fx.bcx.switch_to_block(unsupported_leaf);
-    crate::trap::trap_unreachable(
+    crate::trap::trap_unimplemented(
         fx,
         "__cpuid_count arch intrinsic doesn't yet support specified leaf",
     );

src/intrinsics/llvm.rs

@@ -139,6 +139,7 @@ pub(crate) fn codegen_llvm_intrinsic_call<'tcx>(
                 .sess
                 .warn(&format!("unsupported llvm intrinsic {}; replacing with trap", intrinsic));
             crate::trap::trap_unimplemented(fx, intrinsic);
+            return;
         }
     }
 

src/intrinsics/mod.rs

@@ -44,7 +44,7 @@ fn report_atomic_type_validation_error<'tcx>(
         ),
     );
     // Prevent verifier error
-    crate::trap::trap_unreachable(fx, "compilation should not have succeeded");
+    fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
 }
 
 pub(crate) fn clif_vector_type<'tcx>(tcx: TyCtxt<'tcx>, layout: TyAndLayout<'tcx>) -> Option<Type> {
@@ -849,8 +849,6 @@ fn codegen_regular_intrinsic_call<'tcx>(
                     if fx.tcx.is_compiler_builtins(LOCAL_CRATE) {
                         // special case for compiler-builtins to avoid having to patch it
                         crate::trap::trap_unimplemented(fx, "128bit atomics not yet supported");
-                        let ret_block = fx.get_block(destination.unwrap());
-                        fx.bcx.ins().jump(ret_block, &[]);
                         return;
                     } else {
                         fx.tcx
@@ -882,8 +880,6 @@ fn codegen_regular_intrinsic_call<'tcx>(
                     if fx.tcx.is_compiler_builtins(LOCAL_CRATE) {
                         // special case for compiler-builtins to avoid having to patch it
                         crate::trap::trap_unimplemented(fx, "128bit atomics not yet supported");
-                        let ret_block = fx.get_block(destination.unwrap());
-                        fx.bcx.ins().jump(ret_block, &[]);
                         return;
                     } else {
                         fx.tcx

src/intrinsics/simd.rs

@@ -14,7 +14,7 @@ fn report_simd_type_validation_error(
 ) {
     fx.tcx.sess.span_err(span, &format!("invalid monomorphization of `{}` intrinsic: expected SIMD input type, found non-SIMD `{}`", intrinsic, ty));
     // Prevent verifier error
-    crate::trap::trap_unreachable(fx, "compilation should not have succeeded");
+    fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
 }
 
 pub(super) fn codegen_simd_intrinsic_call<'tcx>(
@@ -157,7 +157,7 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
                             ),
                         );
                         // Prevent verifier error
-                        crate::trap::trap_unreachable(fx, "compilation should not have succeeded");
+                        fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
                         return;
                     }
                 }
@@ -274,12 +274,17 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
                 idx_const
             } else {
                 fx.tcx.sess.span_warn(span, "Index argument for `simd_extract` is not a constant");
-                let res = crate::trap::trap_unimplemented_ret_value(
+                let trap_block = fx.bcx.create_block();
+                let dummy_block = fx.bcx.create_block();
+                let true_ = fx.bcx.ins().iconst(types::I8, 1);
+                fx.bcx.ins().brnz(true_, trap_block, &[]);
+                fx.bcx.ins().jump(dummy_block, &[]);
+                fx.bcx.switch_to_block(trap_block);
+                crate::trap::trap_unimplemented(
                     fx,
-                    ret.layout(),
                     "Index argument for `simd_extract` is not a constant",
                 );
-                ret.write_cvalue(fx, res);
+                fx.bcx.switch_to_block(dummy_block);
                 return;
             };
 

src/trap.rs

@@ -25,33 +25,10 @@ fn codegen_print(fx: &mut FunctionCx<'_, '_, '_>, msg: &str) {
     fx.bcx.ins().call(puts, &[msg_ptr]);
 }
 
-/// Use this for example when a function call should never return. This will fill the current block,
-/// so you can **not** add instructions to it afterwards.
-///
-/// Trap code: user65535
-pub(crate) fn trap_unreachable(fx: &mut FunctionCx<'_, '_, '_>, msg: impl AsRef<str>) {
-    codegen_print(fx, msg.as_ref());
-    fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
-}
 /// Use this when something is unimplemented, but `libcore` or `libstd` requires it to codegen.
-/// Unlike `trap_unreachable` this will not fill the current block, so you **must** add instructions
-/// to it afterwards.
 ///
 /// Trap code: user65535
 pub(crate) fn trap_unimplemented(fx: &mut FunctionCx<'_, '_, '_>, msg: impl AsRef<str>) {
     codegen_print(fx, msg.as_ref());
-    let true_ = fx.bcx.ins().iconst(types::I32, 1);
-    fx.bcx.ins().trapnz(true_, TrapCode::User(!0));
-}
-
-/// Like `trap_unimplemented` but returns a fake value of the specified type.
-///
-/// Trap code: user65535
-pub(crate) fn trap_unimplemented_ret_value<'tcx>(
-    fx: &mut FunctionCx<'_, '_, 'tcx>,
-    dest_layout: TyAndLayout<'tcx>,
-    msg: impl AsRef<str>,
-) -> CValue<'tcx> {
-    trap_unimplemented(fx, msg);
-    CValue::by_ref(Pointer::const_addr(fx, 0), dest_layout)
+    fx.bcx.ins().trap(TrapCode::User(!0));
 }