Stage2 bit_shifting.zig passing

src/Module.zig

@@ -831,6 +831,10 @@ pub const Struct = struct {
         have_field_types,
         layout_wip,
         have_layout,
+        fully_resolved_wip,
+        // The types and all its fields have had their layout resolved. Even through pointer,
+        // which `have_layout` does not ensure.
+        fully_resolved,
     },
     /// If true, definitely nonzero size at runtime. If false, resolving the fields
     /// is necessary to determine whether it has bits at runtime.
@@ -889,6 +893,22 @@ pub const Struct = struct {
             .have_field_types,
             .layout_wip,
             .have_layout,
+            .fully_resolved_wip,
+            .fully_resolved,
+            => true,
+        };
+    }
+
+    pub fn haveLayout(s: Struct) bool {
+        return switch (s.status) {
+            .none,
+            .field_types_wip,
+            .have_field_types,
+            .layout_wip,
+            => false,
+            .have_layout,
+            .fully_resolved_wip,
+            .fully_resolved,
             => true,
         };
     }
@@ -1003,6 +1023,10 @@ pub const Union = struct {
         have_field_types,
         layout_wip,
         have_layout,
+        fully_resolved_wip,
+        // The types and all its fields have had their layout resolved. Even through pointer,
+        // which `have_layout` does not ensure.
+        fully_resolved,
     },
 
     pub const Field = struct {
@@ -1033,6 +1057,8 @@ pub const Union = struct {
             .have_field_types,
             .layout_wip,
             .have_layout,
+            .fully_resolved_wip,
+            .fully_resolved,
             => true,
         };
     }
@@ -1102,8 +1128,22 @@ pub const Union = struct {
         tag_size: u64,
     };
 
+    pub fn haveLayout(u: Union) bool {
+        return switch (u.status) {
+            .none,
+            .field_types_wip,
+            .have_field_types,
+            .layout_wip,
+            => false,
+            .have_layout,
+            .fully_resolved_wip,
+            .fully_resolved,
+            => true,
+        };
+    }
+
     pub fn getLayout(u: Union, target: Target, have_tag: bool) Layout {
-        assert(u.status == .have_layout);
+        assert(u.haveLayout());
         var most_aligned_field: u32 = undefined;
         var most_aligned_field_size: u64 = undefined;
         var biggest_field: u32 = undefined;
@@ -4397,6 +4437,7 @@ pub fn analyzeFnBody(mod: *Module, decl: *Decl, func: *Fn, arena: Allocator) Sem
             const arg = try sema.addConstant(param_type, opv);
             sema.inst_map.putAssumeCapacityNoClobber(inst, arg);
             total_param_index += 1;
+            runtime_param_index += 1;
             continue;
         }
         const ty_ref = try sema.addType(param_type);

src/Sema.zig

@@ -4503,14 +4503,14 @@ fn analyzeCall(
             const arg_src = call_src; // TODO: better source location
             if (i < fn_params_len) {
                 const param_ty = func_ty.fnParamType(i);
-                try sema.resolveTypeForCodegen(block, arg_src, param_ty);
+                try sema.resolveTypeFully(block, arg_src, param_ty);
                 args[i] = try sema.coerce(block, param_ty, uncasted_arg, arg_src);
             } else {
                 args[i] = uncasted_arg;
             }
         }
 
-        try sema.resolveTypeForCodegen(block, call_src, func_ty_info.return_type);
+        try sema.resolveTypeFully(block, call_src, func_ty_info.return_type);
 
         try sema.air_extra.ensureUnusedCapacity(gpa, @typeInfo(Air.Call).Struct.fields.len +
             args.len);
@@ -4580,15 +4580,15 @@ fn finishGenericCall(
                 const param_ty = new_fn_ty.fnParamType(runtime_i);
                 const arg_src = call_src; // TODO: better source location
                 const uncasted_arg = uncasted_args[total_i];
-                try sema.resolveTypeForCodegen(block, arg_src, param_ty);
+                try sema.resolveTypeFully(block, arg_src, param_ty);
                 const casted_arg = try sema.coerce(block, param_ty, uncasted_arg, arg_src);
                 runtime_args[runtime_i] = casted_arg;
                 runtime_i += 1;
             }
             total_i += 1;
         }
 
-        try sema.resolveTypeForCodegen(block, call_src, new_fn_ty.fnReturnType());
+        try sema.resolveTypeFully(block, call_src, new_fn_ty.fnReturnType());
     }
     try sema.air_extra.ensureUnusedCapacity(sema.gpa, @typeInfo(Air.Call).Struct.fields.len +
         runtime_args_len);
@@ -7318,8 +7318,8 @@ fn zirShr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Ins
     const lhs = sema.resolveInst(extra.lhs);
     const rhs = sema.resolveInst(extra.rhs);
 
-    if (try sema.resolveMaybeUndefVal(block, lhs_src, lhs)) |lhs_val| {
-        if (try sema.resolveMaybeUndefVal(block, rhs_src, rhs)) |rhs_val| {
+    if (try sema.resolveMaybeUndefVal(block, rhs_src, rhs)) |rhs_val| {
+        if (try sema.resolveMaybeUndefVal(block, lhs_src, lhs)) |lhs_val| {
             const lhs_ty = sema.typeOf(lhs);
             if (lhs_val.isUndef() or rhs_val.isUndef()) {
                 return sema.addConstUndef(lhs_ty);
@@ -7331,6 +7331,12 @@ fn zirShr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Ins
             const val = try lhs_val.shr(rhs_val, sema.arena);
             return sema.addConstant(lhs_ty, val);
         }
+        // Even if lhs is not comptime known, we can still deduce certain things based
+        // on rhs.
+        // If rhs is 0, return lhs without doing any calculations.
+        else if (rhs_val.compareWithZero(.eq)) {
+            return lhs;
+        }
     }
 
     try sema.requireRuntimeBlock(block, src);
@@ -15222,7 +15228,7 @@ fn resolveStructLayout(
         .field_types_wip, .layout_wip => {
             return sema.fail(block, src, "struct {} depends on itself", .{ty});
         },
-        .have_layout => return,
+        .have_layout, .fully_resolved_wip, .fully_resolved => return,
     }
     struct_obj.status = .layout_wip;
     for (struct_obj.fields.values()) |field| {
@@ -15244,7 +15250,7 @@ fn resolveUnionLayout(
         .field_types_wip, .layout_wip => {
             return sema.fail(block, src, "union {} depends on itself", .{ty});
         },
-        .have_layout => return,
+        .have_layout, .fully_resolved_wip, .fully_resolved => return,
     }
     union_obj.status = .layout_wip;
     for (union_obj.fields.values()) |field| {
@@ -15253,7 +15259,7 @@ fn resolveUnionLayout(
     union_obj.status = .have_layout;
 }
 
-fn resolveTypeForCodegen(
+fn resolveTypeFully(
     sema: *Sema,
     block: *Block,
     src: LazySrcLoc,
@@ -15262,20 +15268,67 @@ fn resolveTypeForCodegen(
     switch (ty.zigTypeTag()) {
         .Pointer => {
             const child_ty = try sema.resolveTypeFields(block, src, ty.childType());
-            return resolveTypeForCodegen(sema, block, src, child_ty);
+            return resolveTypeFully(sema, block, src, child_ty);
         },
-        .Struct => return resolveStructLayout(sema, block, src, ty),
-        .Union => return resolveUnionLayout(sema, block, src, ty),
-        .Array => return resolveTypeForCodegen(sema, block, src, ty.childType()),
+        .Struct => return resolveStructFully(sema, block, src, ty),
+        .Union => return resolveUnionFully(sema, block, src, ty),
+        .Array => return resolveTypeFully(sema, block, src, ty.childType()),
         .Optional => {
             var buf: Type.Payload.ElemType = undefined;
-            return resolveTypeForCodegen(sema, block, src, ty.optionalChild(&buf));
+            return resolveTypeFully(sema, block, src, ty.optionalChild(&buf));
         },
-        .ErrorUnion => return resolveTypeForCodegen(sema, block, src, ty.errorUnionPayload()),
+        .ErrorUnion => return resolveTypeFully(sema, block, src, ty.errorUnionPayload()),
         else => {},
     }
 }
 
+fn resolveStructFully(
+    sema: *Sema,
+    block: *Block,
+    src: LazySrcLoc,
+    ty: Type,
+) CompileError!void {
+    try resolveStructLayout(sema, block, src, ty);
+
+    const resolved_ty = try sema.resolveTypeFields(block, src, ty);
+    const struct_obj = resolved_ty.castTag(.@"struct").?.data;
+    switch (struct_obj.status) {
+        .none, .have_field_types, .field_types_wip, .layout_wip, .have_layout => {},
+        .fully_resolved_wip, .fully_resolved => return,
+    }
+
+    // After we have resolve struct layout we have to go over the fields again to
+    // make sure pointer fields get their child types resolved as well
+    struct_obj.status = .fully_resolved_wip;
+    for (struct_obj.fields.values()) |field| {
+        try sema.resolveTypeFully(block, src, field.ty);
+    }
+    struct_obj.status = .fully_resolved;
+}
+
+fn resolveUnionFully(
+    sema: *Sema,
+    block: *Block,
+    src: LazySrcLoc,
+    ty: Type,
+) CompileError!void {
+    try resolveUnionLayout(sema, block, src, ty);
+
+    const resolved_ty = try sema.resolveTypeFields(block, src, ty);
+    const union_obj = resolved_ty.cast(Type.Payload.Union).?.data;
+    switch (union_obj.status) {
+        .none, .have_field_types, .field_types_wip, .layout_wip, .have_layout => {},
+        .fully_resolved_wip, .fully_resolved => return,
+    }
+
+    // Same goes for unions (see comment about structs)
+    union_obj.status = .fully_resolved_wip;
+    for (union_obj.fields.values()) |field| {
+        try sema.resolveTypeFully(block, src, field.ty);
+    }
+    union_obj.status = .fully_resolved;
+}
+
 fn resolveTypeFields(sema: *Sema, block: *Block, src: LazySrcLoc, ty: Type) CompileError!Type {
     switch (ty.tag()) {
         .@"struct" => {
@@ -15285,7 +15338,12 @@ fn resolveTypeFields(sema: *Sema, block: *Block, src: LazySrcLoc, ty: Type) Comp
                 .field_types_wip => {
                     return sema.fail(block, src, "struct {} depends on itself", .{ty});
                 },
-                .have_field_types, .have_layout, .layout_wip => return ty,
+                .have_field_types,
+                .have_layout,
+                .layout_wip,
+                .fully_resolved_wip,
+                .fully_resolved,
+                => return ty,
             }
 
             struct_obj.status = .field_types_wip;
@@ -15318,7 +15376,12 @@ fn resolveTypeFields(sema: *Sema, block: *Block, src: LazySrcLoc, ty: Type) Comp
                 .field_types_wip => {
                     return sema.fail(block, src, "union {} depends on itself", .{ty});
                 },
-                .have_field_types, .have_layout, .layout_wip => return ty,
+                .have_field_types,
+                .have_layout,
+                .layout_wip,
+                .fully_resolved_wip,
+                .fully_resolved,
+                => return ty,
             }
 
             union_obj.status = .field_types_wip;

src/codegen/llvm.zig

@@ -2647,7 +2647,7 @@ pub const FuncGen = struct {
         switch (struct_ty.zigTypeTag()) {
             .Struct => {
                 var ptr_ty_buf: Type.Payload.Pointer = undefined;
-                const llvm_field_index = llvmFieldIndex(struct_ty, field_index, target, &ptr_ty_buf);
+                const llvm_field_index = llvmFieldIndex(struct_ty, field_index, target, &ptr_ty_buf).?;
                 const field_ptr = self.builder.buildStructGEP(struct_llvm_val, llvm_field_index, "");
                 const field_ptr_ty = Type.initPayload(&ptr_ty_buf.base);
                 return self.load(field_ptr, field_ptr_ty);
@@ -4354,8 +4354,18 @@ pub const FuncGen = struct {
             .Struct => {
                 const target = self.dg.module.getTarget();
                 var ty_buf: Type.Payload.Pointer = undefined;
-                const llvm_field_index = llvmFieldIndex(struct_ty, field_index, target, &ty_buf);
-                return self.builder.buildStructGEP(struct_ptr, llvm_field_index, "");
+                if (llvmFieldIndex(struct_ty, field_index, target, &ty_buf)) |llvm_field_index| {
+                    return self.builder.buildStructGEP(struct_ptr, llvm_field_index, "");
+                } else {
+                    // If we found no index then this means this is a zero sized field at the
+                    // end of the struct. Treat our struct pointer as an array of two and get
+                    // the index to the element at index `1` to get a pointer to the end of
+                    // the struct.
+                    const llvm_usize = try self.dg.llvmType(Type.usize);
+                    const llvm_index = llvm_usize.constInt(1, .False);
+                    const indices: [1]*const llvm.Value = .{llvm_index};
+                    return self.builder.buildInBoundsGEP(struct_ptr, &indices, indices.len, "");
+                }
             },
             .Union => return self.unionFieldPtr(inst, struct_ptr, struct_ty, field_index),
             else => unreachable,
@@ -4750,32 +4760,37 @@ fn toLlvmCallConv(cc: std.builtin.CallingConvention, target: std.Target) llvm.Ca
     };
 }
 
-/// Take into account 0 bit fields.
+/// Take into account 0 bit fields. Returns null if an llvm field could not be found. This only
+/// happends if you want the field index of a zero sized field at the end of the struct.
 fn llvmFieldIndex(
     ty: Type,
     field_index: u32,
     target: std.Target,
     ptr_pl_buf: *Type.Payload.Pointer,
-) c_uint {
+) ?c_uint {
     const struct_obj = ty.castTag(.@"struct").?.data;
     if (struct_obj.layout != .Packed) {
         var llvm_field_index: c_uint = 0;
         for (struct_obj.fields.values()) |field, i| {
-            if (!field.ty.hasCodeGenBits()) continue;
-
-            if (i == field_index) {
-                ptr_pl_buf.* = .{
-                    .data = .{
-                        .pointee_type = field.ty,
-                        .@"align" = field.normalAlignment(target),
-                        .@"addrspace" = .generic,
-                    },
-                };
-                return llvm_field_index;
+            if (!field.ty.hasCodeGenBits())
+                continue;
+            if (field_index > i) {
+                llvm_field_index += 1;
+                continue;
             }
-            llvm_field_index += 1;
+
+            ptr_pl_buf.* = .{
+                .data = .{
+                    .pointee_type = field.ty,
+                    .@"align" = field.normalAlignment(target),
+                    .@"addrspace" = .generic,
+                },
+            };
+            return llvm_field_index;
+        } else {
+            // We did not find an llvm field that corrispons to this zig field.
+            return null;
         }
-        unreachable;
     }
 
     // Our job here is to return the host integer field index.
@@ -4784,7 +4799,8 @@ fn llvmFieldIndex(
     var running_bits: u16 = 0;
     var llvm_field_index: c_uint = 0;
     for (struct_obj.fields.values()) |field, i| {
-        if (!field.ty.hasCodeGenBits()) continue;
+        if (!field.ty.hasCodeGenBits())
+            continue;
 
         const field_align = field.packedAlignment();
         if (field_align == 0) {

src/type.zig

@@ -1916,7 +1916,7 @@ pub const Type = extern union {
                 const fields = self.structFields();
                 const is_packed = if (self.castTag(.@"struct")) |payload| p: {
                     const struct_obj = payload.data;
-                    assert(struct_obj.status == .have_layout);
+                    assert(struct_obj.haveLayout());
                     break :p struct_obj.layout == .Packed;
                 } else false;
 
@@ -2220,7 +2220,7 @@ pub const Type = extern union {
                 if (field_count == 0) return 0;
 
                 const struct_obj = ty.castTag(.@"struct").?.data;
-                assert(struct_obj.status == .have_layout);
+                assert(struct_obj.haveLayout());
 
                 var total: u64 = 0;
                 for (struct_obj.fields.values()) |field| {
@@ -3771,7 +3771,7 @@ pub const Type = extern union {
         switch (ty.tag()) {
             .@"struct" => {
                 const struct_obj = ty.castTag(.@"struct").?.data;
-                assert(struct_obj.status == .have_layout);
+                assert(struct_obj.haveLayout());
                 const is_packed = struct_obj.layout == .Packed;
                 if (!is_packed) {
                     var offset: u64 = 0;