Merge branch 'master' of https://github.com/ziglang/zig into tuple_concat

1 files changed, 33 insertions, 3 deletions

diff --git a/src/ir.cpp b/src/ir.cpp
index 977c4b65eb..dd977acd73 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -17829,6 +17829,7 @@ static IrInstGen *ir_analyze_instruction_export(IrAnalyze *ira, IrInstSrcExport
             }
         } break;
         case ZigTypeIdInt:
+            want_var_export = true;
             break;
         case ZigTypeIdVoid:
         case ZigTypeIdBool:
@@ -20399,6 +20400,17 @@ static ZigType *adjust_ptr_len(CodeGen *g, ZigType *ptr_type, PtrLen ptr_len) {
             ptr_type->data.pointer.allow_zero);
 }
 
+static ZigType *adjust_ptr_allow_zero(CodeGen *g, ZigType *ptr_type, bool allow_zero) {
+    assert(ptr_type->id == ZigTypeIdPointer);
+    return get_pointer_to_type_extra(g,
+            ptr_type->data.pointer.child_type,
+            ptr_type->data.pointer.is_const, ptr_type->data.pointer.is_volatile,
+            ptr_type->data.pointer.ptr_len,
+            ptr_type->data.pointer.explicit_alignment,
+            ptr_type->data.pointer.bit_offset_in_host, ptr_type->data.pointer.host_int_bytes,
+            allow_zero);
+}
+
 static IrInstGen *ir_analyze_instruction_elem_ptr(IrAnalyze *ira, IrInstSrcElemPtr *elem_ptr_instruction) {
     Error err;
     IrInstGen *array_ptr = elem_ptr_instruction->array_ptr->child;
@@ -25956,6 +25968,8 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
     ZigType *non_sentinel_slice_ptr_type;
     ZigType *elem_type;
 
+    bool generate_non_null_assert = false;
+
     if (array_type->id == ZigTypeIdArray) {
         elem_type = array_type->data.array.child_type;
         bool is_comptime_const = ptr_ptr->value->special == ConstValSpecialStatic &&
@@ -25983,6 +25997,14 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
             elem_type = array_type->data.pointer.child_type;
             if (array_type->data.pointer.ptr_len == PtrLenC) {
                 array_type = adjust_ptr_len(ira->codegen, array_type, PtrLenUnknown);
+
+                // C pointers are allowzero by default.  
+                // However, we want to be able to slice them without generating an allowzero slice (see issue #4401).
+                // To achieve this, we generate a runtime safety check and make the slice type non-allowzero.
+                if (array_type->data.pointer.allow_zero) {
+                    array_type = adjust_ptr_allow_zero(ira->codegen, array_type, false);
+                    generate_non_null_assert = true;
+                }
             }
             ZigType *maybe_sentineled_slice_ptr_type = array_type;
             non_sentinel_slice_ptr_type = adjust_ptr_sentinel(ira->codegen, maybe_sentineled_slice_ptr_type, nullptr);
@@ -26254,7 +26276,6 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
 
     IrInstGen *result_loc = ir_resolve_result(ira, &instruction->base.base, instruction->result_loc,
             return_type, nullptr, true, true);
-
     if (result_loc != nullptr) {
         if (type_is_invalid(result_loc->value->type) || result_loc->value->type->id == ZigTypeIdUnreachable) {
             return result_loc;
@@ -26267,8 +26288,17 @@ static IrInstGen *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstSrcSlice *i
             return ira->codegen->invalid_inst_gen;
     }
 
-    return ir_build_slice_gen(ira, &instruction->base.base, return_type,
-        ptr_ptr, casted_start, end, instruction->safety_check_on, result_loc);
+    if (generate_non_null_assert) {
+        IrInstGen *ptr_val = ir_get_deref(ira, &instruction->base.base, ptr_ptr, nullptr);
+
+        if (type_is_invalid(ptr_val->value->type))
+            return ira->codegen->invalid_inst_gen;
+    
+        ir_build_assert_non_null(ira, &instruction->base.base, ptr_val);
+    }
+
+    return ir_build_slice_gen(ira, &instruction->base.base, return_type, ptr_ptr,
+            casted_start, end, instruction->safety_check_on, result_loc);
 }
 
 static IrInstGen *ir_analyze_instruction_has_field(IrAnalyze *ira, IrInstSrcHasField *instruction) {