[m-dev.] for review: ANSI C fixes for none.x grades

[Fergus Henderson]

On 25-Nov-1999, Fergus Henderson <fjh at cs.mu.OZ.AU> wrote:
> Peter Ross wrote:
> > is it possible for something to be Declare_static and for this
> > to be the only declaration?
> 
> No -- in llds_out.m, in output_single_c_file, the first thing it does
> is to calls gather_c_labels and then output_c_label_decl_list
> to output declarations of all the labels defined in that C file.

Oops, I misread the code: it just outputs declarations of all the
labels *referenced* in that C file, not the labels defined in that C file.
So the declaration is *not* unnecessary.  Sorry about the incorrect
advice. 

Anyway, because of this, the change that you committed broke --split-c-files.
So I've just committed the following change to fix it.
The solution is rather obvious in retrospect: put the declaration
at file scope rather than using a nested declaration.
(The reasons that the current code uses a nested declaration
are entirely hysterical raisins.)

----------

Estimated hours taken: 0.75

compiler/export.m:
	Fix a bug in petdr's recent change to export.m: it turns out
	that the Declare_static() declarations that I had said were not
	needed are indeed needed.  To make it valid ANSI C, I changed the
	code to put the declaration at file scope rather than using a nested
	declaration.

Workspace: /home/mercury0/fjh/mercury
Index: compiler/export.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/export.m,v
retrieving revision 1.30
diff -u -d -r1.30 export.m
--- export.m	1999/11/25 09:09:31	1.30
+++ export.m	1999/11/28 07:54:13
@@ -104,6 +104,8 @@
 	% For each exported procedure, produce a C function.
 	% The code we generate is in the form
 	%
+	% Declare_entry(<label of called proc>); /* or Declare_static */
+	%
 	% #if SEMIDET
 	%   bool
 	% #elif FUNCTION
@@ -133,11 +135,9 @@
 	%		/* save the registers which may be clobbered      */
 	%		/* by the C function call MR_call_engine().       */
 	%	save_transient_registers();
-	%	{
-	%		/* The Declare_entry may not be necessary	  */
-	%       Declare_entry(<label of called proc>);
+	%
 	%	(void) MR_call_engine(ENTRY(<label of called proc>), FALSE);
-	%	}
+	%
 	%		/* restore the registers which may have been      */
 	%		/* clobbered by the return from the C function    */
 	%		/* MR_call_engine()				  */
@@ -179,13 +179,14 @@
 	llds_out__get_proc_label(ProcLabel, yes, ProcLabelString),
 
 	( Exported = yes ->
-		string__append_list(["Declare_entry", "(",
-				ProcLabelString, ");\n"], DeclareString)
+		DeclareString = "Declare_entry"
 	;
-		DeclareString = ""
+		DeclareString = "Declare_static"
 	),
 
 	string__append_list([	"\n",
+				DeclareString, "(", ProcLabelString, ");\n",
+				"\n",
 				C_RetType, "\n", 
 				C_Function, "(", ArgDecls, ")\n{\n",
 				"#if NUM_REAL_REGS > 0\n",
@@ -197,11 +198,8 @@
 				"\trestore_registers();\n", 
 				InputArgs,
 				"\tsave_transient_registers();\n",
-				"\t{\n\t",
-				DeclareString,
 				"\t(void) MR_call_engine(ENTRY(",
-				ProcLabelString,
-				"), FALSE);\n\t}\n",
+					ProcLabelString, "), FALSE);\n",
 				"\trestore_transient_registers();\n",
 				MaybeFail,
 				OutputArgs,

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>  |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3        |     -- the last words of T. S. Garp.
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