Merge pull request #13288 from Vexu/opt-slice

Optimize size of optional slices (+ some fixes)

2 files changed, 31 insertions, 13 deletions

diff --git a/src/codegen/c.zig b/src/codegen/c.zig
index d0f76f0390..6ae11c500d 100644
--- a/src/codegen/c.zig
+++ b/src/codegen/c.zig
@@ -730,7 +730,11 @@ pub const DeclGen = struct {
                 }
 
                 if (ty.optionalReprIsPayload()) {
-                    return dg.renderValue(writer, payload_ty, val, location);
+                    if (val.castTag(.opt_payload)) |payload| {
+                        return dg.renderValue(writer, payload_ty, payload.data, location);
+                    } else {
+                        return dg.renderValue(writer, payload_ty, val, location);
+                    }
                 }
 
                 try writer.writeByte('(');
@@ -3267,11 +3271,9 @@ fn airIsNull(
     try f.writeCValue(writer, operand);
 
     const ty = f.air.typeOf(un_op);
+    const opt_ty = if (deref_suffix[0] != 0) ty.childType() else ty;
     var opt_buf: Type.Payload.ElemType = undefined;
-    const payload_ty = if (deref_suffix[0] != 0)
-        ty.childType().optionalChild(&opt_buf)
-    else
-        ty.optionalChild(&opt_buf);
+    const payload_ty = opt_ty.optionalChild(&opt_buf);
 
     if (!payload_ty.hasRuntimeBitsIgnoreComptime()) {
         try writer.print("){s} {s} true;\n", .{ deref_suffix, operator });
@@ -3280,6 +3282,8 @@ fn airIsNull(
         try writer.print("){s} {s} NULL;\n", .{ deref_suffix, operator });
     } else if (payload_ty.zigTypeTag() == .ErrorSet) {
         try writer.print("){s} {s} 0;\n", .{ deref_suffix, operator });
+    } else if (payload_ty.isSlice() and opt_ty.optionalReprIsPayload()) {
+        try writer.print("){s}.ptr {s} NULL;\n", .{ deref_suffix, operator });
     } else {
         try writer.print("){s}.is_null {s} true;\n", .{ deref_suffix, operator });
     }
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 1c2d65246f..d92a444ea4 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -1027,7 +1027,9 @@ pub const Object = struct {
                             dg.addArgAttr(llvm_func, llvm_arg_i, "noalias");
                         }
                     }
-                    dg.addArgAttr(llvm_func, llvm_arg_i, "nonnull");
+                    if (param_ty.zigTypeTag() != .Optional) {
+                        dg.addArgAttr(llvm_func, llvm_arg_i, "nonnull");
+                    }
                     if (!ptr_info.mutable) {
                         dg.addArgAttr(llvm_func, llvm_arg_i, "readonly");
                     }
@@ -1916,7 +1918,7 @@ pub const Object = struct {
 
                 if (ty.castTag(.@"struct")) |payload| {
                     const struct_obj = payload.data;
-                    if (struct_obj.layout == .Packed) {
+                    if (struct_obj.layout == .Packed and struct_obj.haveFieldTypes()) {
                         const info = struct_obj.backing_int_ty.intInfo(target);
                         const dwarf_encoding: c_uint = switch (info.signedness) {
                             .signed => DW.ATE.signed,
@@ -3117,7 +3119,11 @@ pub const DeclGen = struct {
             .slice => {
                 const param_ty = fn_info.param_types[it.zig_index - 1];
                 var buf: Type.SlicePtrFieldTypeBuffer = undefined;
-                const ptr_ty = param_ty.slicePtrFieldType(&buf);
+                var opt_buf: Type.Payload.ElemType = undefined;
+                const ptr_ty = if (param_ty.zigTypeTag() == .Optional)
+                    param_ty.optionalChild(&opt_buf).slicePtrFieldType(&buf)
+                else
+                    param_ty.slicePtrFieldType(&buf);
                 const ptr_llvm_ty = try dg.lowerType(ptr_ty);
                 const len_llvm_ty = try dg.lowerType(Type.usize);
 
@@ -5438,10 +5444,11 @@ pub const FuncGen = struct {
         const llvm_usize = try self.dg.lowerType(Type.usize);
         const len = llvm_usize.constInt(array_ty.arrayLen(), .False);
         const slice_llvm_ty = try self.dg.lowerType(self.air.typeOfIndex(inst));
+        const operand = try self.resolveInst(ty_op.operand);
         if (!array_ty.hasRuntimeBitsIgnoreComptime()) {
-            return self.builder.buildInsertValue(slice_llvm_ty.getUndef(), len, 1, "");
+            const partial = self.builder.buildInsertValue(slice_llvm_ty.getUndef(), operand, 0, "");
+            return self.builder.buildInsertValue(partial, len, 1, "");
         }
-        const operand = try self.resolveInst(ty_op.operand);
         const indices: [2]*llvm.Value = .{
             llvm_usize.constNull(), llvm_usize.constNull(),
         };
@@ -6320,18 +6327,24 @@ pub const FuncGen = struct {
         const operand_ty = self.air.typeOf(un_op);
         const optional_ty = if (operand_is_ptr) operand_ty.childType() else operand_ty;
         const optional_llvm_ty = try self.dg.lowerType(optional_ty);
+        var buf: Type.Payload.ElemType = undefined;
+        const payload_ty = optional_ty.optionalChild(&buf);
         if (optional_ty.optionalReprIsPayload()) {
             const loaded = if (operand_is_ptr)
                 self.builder.buildLoad(optional_llvm_ty, operand, "")
             else
                 operand;
+            if (payload_ty.isSlice()) {
+                const slice_ptr = self.builder.buildExtractValue(loaded, 0, "");
+                var slice_buf: Type.SlicePtrFieldTypeBuffer = undefined;
+                const ptr_ty = try self.dg.lowerType(payload_ty.slicePtrFieldType(&slice_buf));
+                return self.builder.buildICmp(pred, slice_ptr, ptr_ty.constNull(), "");
+            }
             return self.builder.buildICmp(pred, loaded, optional_llvm_ty.constNull(), "");
         }
 
         comptime assert(optional_layout_version == 3);
 
-        var buf: Type.Payload.ElemType = undefined;
-        const payload_ty = optional_ty.optionalChild(&buf);
         if (!payload_ty.hasRuntimeBitsIgnoreComptime()) {
             const loaded = if (operand_is_ptr)
                 self.builder.buildLoad(optional_llvm_ty, operand, "")
@@ -10355,7 +10368,8 @@ const ParamTypeIterator = struct {
             .Unspecified, .Inline => {
                 it.zig_index += 1;
                 it.llvm_index += 1;
-                if (ty.isSlice()) {
+                var buf: Type.Payload.ElemType = undefined;
+                if (ty.isSlice() or (ty.zigTypeTag() == .Optional and ty.optionalChild(&buf).isSlice())) {
                     return .slice;
                 } else if (isByRef(ty)) {
                     return .byref;