From 3902cb2fcae6e2028252b5d2016bf0e99ed74980 Mon Sep 17 00:00:00 2001
From: Flavio Cruz <flaviocruz@gmail.com>
Date: Fri, 4 Nov 2022 01:29:37 -0400
Subject: Add support to define structures in mig.

Basic syntax is presented below and allows users to define
nested structured types by using simpler or structure types as
members. Mig will use the C padding and alignment rules to produce
the same size as the corresponding C structures.

type timespec_t = struct {
  uint32_t tv_sec;
  uint32_t tv_nsec;
};

This allows us to build stubs that are more easily adaptable to other
architectures.
Message-Id: <Y2SjQSMOINY8I5Dy@viriathus>
---
 parser.y | 46 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 45 insertions(+), 1 deletion(-)

(limited to 'parser.y')

diff --git a/parser.y b/parser.y
index 8521a84..104f604 100644
--- a/parser.y
+++ b/parser.y
@@ -84,6 +84,8 @@
 %token	syRAngle
 %token	syLBrack
 %token	syRBrack
+%token	syLCBrack
+%token	syRCBrack
 %token	syBar
 
 %token	syError			/* lex error */
@@ -103,6 +105,7 @@
 
 %type	<statement_kind> ImportIndicant
 %type	<number> VarArrayHead ArrayHead StructHead IntExp
+%type   <structured_type> StructList
 %type	<type> NamedTypeSpec TransTypeSpec TypeSpec
 %type	<type> CStringSpec
 %type	<type> BasicTypeSpec PrevTypeSpec ArgumentType
@@ -124,6 +127,7 @@
 #include "type.h"
 #include "routine.h"
 #include "statement.h"
+#include "utils.h"
 
 static const char *import_name(statement_kind_t sk);
 
@@ -149,6 +153,14 @@ yyerror(const char *s)
 	const_string_t outstr;
 	u_int size;		/* 0 means there is no default size */
     } symtype;
+    /* Holds information about a structure while parsing. */
+    struct
+    {
+        /* The required alignment (in bytes) so far. */
+        u_int type_alignment_in_bytes;
+        /* The size of the struct in bytes so far. */
+        u_int size_in_bytes;
+    } structured_type;
     routine_t *routine;
     arg_kind_t direction;
     argument_t *argument;
@@ -466,11 +478,43 @@ TypeSpec		:	BasicTypeSpec
 			|	syCaret TypeSpec
 				{ $$ = itPtrDecl($2); }
 			|	StructHead TypeSpec
-				{ $$ = itStructDecl($1, $2); }
+				{ $$ = itStructArrayDecl($1, $2); }
+                        |       syStruct syLCBrack StructList syRCBrack
+				{ $$ = itStructDecl($3.size_in_bytes, $3.type_alignment_in_bytes); }
 			|	CStringSpec
 				{ $$ = $1; }
 			;
 
+StructList   		: 	syIdentifier syIdentifier sySemi
+{
+    ipc_type_t *t = itPrevDecl($1);
+    if (!t) {
+        error("Type %s not found\n", $1);
+    }
+    if (!t->itInLine) {
+        error("Type %s must be inline\n", $2);
+    }
+
+    $$.type_alignment_in_bytes = t->itAlignment;
+    $$.size_in_bytes = t->itTypeSize;
+}
+			|	StructList syIdentifier syIdentifier sySemi
+{
+    ipc_type_t *t = itPrevDecl($2);
+    if (!t) {
+        error("Type %s not found\n", $2);
+    }
+    if (!t->itInLine) {
+        error("Type %s must be inline\n", $2);
+    }
+    $$.type_alignment_in_bytes = MAX(t->itAlignment, $1.type_alignment_in_bytes);
+    int padding_bytes = 0;
+    if ($1.size_in_bytes % t->itAlignment)
+        padding_bytes = t->itAlignment - ($1.size_in_bytes % t->itAlignment);
+    $$.size_in_bytes = $1.size_in_bytes + padding_bytes + t->itTypeSize;
+}
+                        ;
+
 BasicTypeSpec		:	IPCType
 {
     $$ = itShortDecl($1.innumber, $1.instr,
-- 
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