Re: RFC: PATCH for multiple-file functions and the treerepresentation

[Jason Merrill <jason at redhat dot com>]

OK, there were several problems with the last patch.  One, there's already
a last_filename.  Two, reusing EXPR_WITH_FILE_LOCATION like this doesn't
mesh well with the statement/expression code distinction.  So I gave up and
introduced a new statement code.  I'm not entirely happy with this
solution, but it works well.  I'm still open to comments, but I'm checking
it in now.

Tested i686-pc-linux-gnu.

2002-01-15  Jason Merrill  <jason@redhat.com>

	* c-common.def (FILE_STMT): New code.
	* c-common.c (statement_code_p): It's a statement.
	* c-common.h (stmt_tree_s): Add x_last_filename.
	(FILE_STMT_FILENAME_NODE, FILE_STMT_FILENAME): New macros.
	(last_expr_filename): New macro.
	* c-semantics.c (begin_stmt_tree): Initialize it.
	(add_stmt): If the filename changed, also insert a
	FILE_STMT.
	(expand_stmt): Handle seeing one.

*** c-common.c.~1~	Mon Jan  7 19:06:42 2002
--- c-common.c	Mon Jan 14 21:26:48 2002
*************** statement_code_p (code)
*** 3111,3116 ****
--- 3111,3117 ----
      case GOTO_STMT:
      case LABEL_STMT:
      case ASM_STMT:
+     case FILE_STMT:
      case CASE_LABEL:
        return 1;
  
*** c-common.h.~1~	Mon Jan  7 19:06:42 2002
--- c-common.h	Mon Jan 14 21:27:46 2002
*************** struct stmt_tree_s {
*** 257,262 ****
--- 257,264 ----
    /* The type of the last expression statement.  (This information is
       needed to implement the statement-expression extension.)  */
    tree x_last_expr_type;
+   /* The last filename we recorded.  */
+   const char *x_last_expr_filename;
    /* In C++, Non-zero if we should treat statements as full
       expressions.  In particular, this variable is no-zero if at the
       end of a statement we should destroy any temporaries created
*************** struct language_function {
*** 296,301 ****
--- 298,307 ----
  
  #define last_expr_type (current_stmt_tree ()->x_last_expr_type)
  
+ /* The name of the last file we have seen.  */
+ 
+ #define last_expr_filename (current_stmt_tree ()->x_last_expr_filename)
+ 
  /* LAST_TREE contains the last statement parsed.  These are chained
     together through the TREE_CHAIN field, but often need to be
     re-organized since the parse is performed bottom-up.  This macro
*************** extern tree strip_array_types           
*** 688,693 ****
--- 694,705 ----
  #define ASM_VOLATILE_P(NODE)			\
    (ASM_CV_QUAL (ASM_STMT_CHECK (NODE)) != NULL_TREE)
  
+ /* The filename we are changing to as of this FILE_STMT.  */
+ #define FILE_STMT_FILENAME_NODE(NODE) \
+   (TREE_OPERAND (FILE_STMT_CHECK (NODE), 0))
+ #define FILE_STMT_FILENAME(NODE) \
+   (IDENTIFIER_POINTER (FILE_STMT_FILENAME_NODE (NODE)))
+ 
  /* The line-number at which a statement began.  But if
     STMT_LINENO_FOR_FN_P does holds, then this macro gives the
     line number for the end of the current function instead.  */
*** c-common.def.~1~	Fri Dec 28 22:38:38 2001
--- c-common.def	Mon Jan 14 21:18:15 2002
*************** DEFTREECODE (ASM_STMT, "asm_stmt", 'e', 
*** 92,97 ****
--- 92,101 ----
     variables declared in this scope.  */
  DEFTREECODE (SCOPE_STMT, "scope_stmt", 'e', 1)
  
+ /* A FILE_STMT marks the spot where a function changes files.  It has no
+    other semantics.  FILE_STMT_FILENAME gives the name.  */
+ DEFTREECODE (FILE_STMT, "file_stmt", 'e', 1)
+ 
  /* Used to represent a CASE_LABEL. The operands are CASE_LOW and
     CASE_HIGH, respectively. If CASE_LOW is NULL_TREE, the label is a
     'default' label. If CASE_HIGH is NULL_TREE, the label is a normal case
*************** DEFTREECODE (STMT_EXPR, "stmt_expr", 'e'
*** 108,110 ****
--- 112,120 ----
     the DECL_INITIAL of that decl is the CONSTRUCTOR that initializes
     the compound literal.  */
  DEFTREECODE (COMPOUND_LITERAL_EXPR, "compound_literal_expr", 'e', 1)
+ 
+ /*
+ Local variables:
+ mode:c
+ End:
+ */
*** c-semantics.c.~1~	Mon Jan  7 19:06:43 2002
--- c-semantics.c	Mon Jan 14 21:34:42 2002
*************** begin_stmt_tree (t)
*** 60,65 ****
--- 60,66 ----
    *t = build_nt (EXPR_STMT, void_zero_node);
    last_tree = *t;
    last_expr_type = NULL_TREE;
+   last_expr_filename = input_filename;
  }
  
  /* T is a statement.  Add it to the statement-tree.  */
*************** tree
*** 68,73 ****
--- 69,87 ----
  add_stmt (t)
       tree t;
  {
+   if (input_filename != last_expr_filename)
+     {
+       /* If the filename has changed, also add in a FILE_STMT.  Do a string
+ 	 compare first, though, as it might be an equivalent string.  */
+       int add = (strcmp (input_filename, last_expr_filename) != 0);
+       last_expr_filename = input_filename;
+       if (add)
+ 	{
+ 	  tree pos = build_nt (FILE_STMT, get_identifier (input_filename));
+ 	  add_stmt (pos);
+ 	}
+     }
+ 
    /* Add T to the statement-tree.  */
    TREE_CHAIN (last_tree) = t;
    last_tree = t;
*************** expand_stmt (t)
*** 760,765 ****
--- 774,783 ----
  
        switch (TREE_CODE (t))
  	{
+ 	case FILE_STMT:
+ 	  input_filename = FILE_STMT_FILENAME (t);
+ 	  break;
+ 
  	case RETURN_STMT:
  	  genrtl_return_stmt (t);
  	  break;