better handling of arrays in packed structs

 * Separate LoadPtr IR instructions into pass1 and pass2 variants.
 * Define `type_size_bits` for extern structs to be the same as
   their `@sizeOf(T) * 8` and allow them in packed structs.
 * More helpful error messages when trying to use types in
   packed structs that are not allowed.
 * Support arrays in packed structs even when they are not
   byte-aligned.
 * Add compile error for using arrays in packed structs when the
   padding bits would be problematic. This is necessary since
   we do not have packed arrays.

closes #677

1 files changed, 8 insertions, 0 deletions

diff --git a/src/all_types.hpp b/src/all_types.hpp
index 0ee0fef2ca..fe36eb3a5d 100644
--- a/src/all_types.hpp
+++ b/src/all_types.hpp
@@ -2119,6 +2119,7 @@ enum IrInstructionId {
     IrInstructionIdUnOp,
     IrInstructionIdBinOp,
     IrInstructionIdLoadPtr,
+    IrInstructionIdLoadPtrGen,
     IrInstructionIdStorePtr,
     IrInstructionIdFieldPtr,
     IrInstructionIdStructFieldPtr,
@@ -2414,6 +2415,13 @@ struct IrInstructionLoadPtr {
     IrInstruction *ptr;
 };
 
+struct IrInstructionLoadPtrGen {
+    IrInstruction base;
+
+    IrInstruction *ptr;
+    LLVMValueRef tmp_ptr;
+};
+
 struct IrInstructionStorePtr {
     IrInstruction base;