Update zig build system to support user defined options

 * Fix assertion failure when switching on type.
   Closes #310
 * Update zig build system to support user defined options.
   See #204
 * fmt.format supports {sNNN} to set padding for a buffer arg.
 * add std.fmt.bufPrint and std.fmt.allocPrint
 * std.hash_map.HashMap.put returns the previous value
 * add std.mem.startsWith

1 files changed, 13 insertions, 1 deletions

diff --git a/src/ir.cpp b/src/ir.cpp
index 1fb839ea9d..a1ccce7f2c 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -57,6 +57,7 @@ static TypeTableEntry *ir_analyze_instruction(IrAnalyze *ira, IrInstruction *ins
 static IrInstruction *ir_implicit_cast(IrAnalyze *ira, IrInstruction *value, TypeTableEntry *expected_type);
 
 ConstExprValue *const_ptr_pointee(ConstExprValue *const_val) {
+    assert(const_val->type->id == TypeTableEntryIdPointer);
     assert(const_val->special == ConstValSpecialStatic);
     switch (const_val->data.x_ptr.special) {
         case ConstPtrSpecialInvalid:
@@ -10350,10 +10351,21 @@ static TypeTableEntry *ir_analyze_instruction_switch_target(IrAnalyze *ira,
     if (type_is_invalid(target_value_ptr->value.type))
         return ira->codegen->builtin_types.entry_invalid;
 
+    if (target_value_ptr->value.type->id == TypeTableEntryIdMetaType) {
+        assert(instr_is_comptime(target_value_ptr));
+        TypeTableEntry *ptr_type = target_value_ptr->value.data.x_type;
+        assert(ptr_type->id == TypeTableEntryIdPointer);
+        ConstExprValue *out_val = ir_build_const_from(ira, &switch_target_instruction->base);
+        out_val->type = ira->codegen->builtin_types.entry_type;
+        out_val->data.x_type = ptr_type->data.pointer.child_type;
+        return out_val->type;
+    }
+
     assert(target_value_ptr->value.type->id == TypeTableEntryIdPointer);
+
     TypeTableEntry *target_type = target_value_ptr->value.type->data.pointer.child_type;
     ConstExprValue *pointee_val = nullptr;
-    if (target_value_ptr->value.special != ConstValSpecialRuntime) {
+    if (instr_is_comptime(target_value_ptr)) {
         pointee_val = const_ptr_pointee(&target_value_ptr->value);
         if (pointee_val->special == ConstValSpecialRuntime)
             pointee_val = nullptr;