PR-108551 gcc/m2/gm2-libs-pim/Termbase.mod:128:1 error end of non-void

cc1gm2 generates an error: control reaches end of non-void function when
compiling Termbase.mod if -Werror=return-type is present.

../gcc/m2/gm2-libs-pim/Termbase.mod: In function 'Termbase_KeyPressed':
../gcc/m2/gm2-libs-pim/Termbase.mod:128:1: error: control reaches end
	of non-void function [-Werror=return-type]
   128 | END KeyPressed ;
       | ^~~

This occurs as cc1gm2 does skips over the <* noreturn *> attribute.  This
patch records the <* noreturn *> attribute in the m2 symbol table and
later on sets TREE_THIS_VOLATILE when creating the function decl.
The patch also contains a fix for the main scaffold which also omitted
a return 0 after the exception handler code.

gcc/m2/ChangeLog:

	* gm2-compiler/M2GCCDeclare.mod: Import IsProcedureNoReturn.
	(DeclareProcedureToGccWholeProgram): New variable declared and set
	returnType.  Pass returnType to BuildEndFunctionDeclaration.
	Extra parameter IsProcedureNoReturn passed to
	BuildEndFunctionDeclaration.
	* gm2-compiler/M2Quads.mod (BuildM2MainFunction): Correct
	scaffold comment and add extra return 0.
	* gm2-compiler/P2Build.bnf: Import BuildNoReturnAttribute.
	(ProcedureHeading): Process EndBuildFormalParameters before
	parsing AttributeNoReturn.
	(DefProcedureHeading): Process EndBuildFormalParameters before
	parsing AttributeNoReturn.
	(AttributeNoReturn): Call BuildNoReturnAttribute.
	* gm2-compiler/P2SymBuild.def (BuildNoReturnAttribute): New
	procedure.
	* gm2-compiler/P2SymBuild.mod (BuildNoReturnAttribute): New
	procedure.
	* gm2-compiler/SymbolTable.def (PutProcedureInline): Corrected
	comment.
	(PutProcedureNoReturn): New procedure.
	(IsProcedureNoReturn): New procedure function.
	* gm2-compiler/SymbolTable.mod (SymProcedure): IsNoReturn
	new field.
	(MakeProcedure): Initialize IsNoReturn to FALSE.
	(PutProcedureNoReturn): New procedure.
	(IsProcedureNoReturn): New procedure function.
	* gm2-gcc/m2decl.cc (m2decl_BuildEndFunctionDeclaration):
	Add extra parameter isnoreturn.  Set TREE_THIS_VOLATILE
	to isnoreturn.
	* gm2-gcc/m2decl.def (BuildEndFunctionDeclaration): Add
	extra parameter isnoreturn.
	* gm2-gcc/m2decl.h (m2decl_BuildEndFunctionDeclaration): Add
	extra parameter isnoreturn.
	* gm2-gcc/m2except.cc (m2except_InitExceptions): Change all
	function decl to pass an extra parameter isnoreturn.

gcc/testsuite/ChangeLog:

	* gm2/warnings/returntype/fail/badreturn.mod: New test.
	* gm2/warnings/returntype/fail/warnings-returntype-fail.exp:
	New test.
	* gm2/warnings/returntype/pass/Termbase.mod: New test.
	* gm2/warnings/returntype/pass/goodreturn.mod: New test.
	* gm2/warnings/returntype/pass/keypressedsimple.mod: New test.
	* gm2/warnings/returntype/pass/warnings-returntype-pass.exp:
	New test.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>

4 files changed, 16 insertions, 10 deletions

diff --git a/gcc/m2/gm2-gcc/m2decl.cc b/gcc/m2/gm2-gcc/m2decl.cc
index fb4d7dc..ab40937 100644
--- a/gcc/m2/gm2-gcc/m2decl.cc
+++ b/gcc/m2/gm2-gcc/m2decl.cc
@@ -211,7 +211,7 @@ tree
 m2decl_BuildEndFunctionDeclaration (location_t location_begin,
                                     location_t location_end, const char *name,
                                     tree returntype, int isexternal,
-                                    int isnested, int ispublic)
+                                    int isnested, int ispublic, int isnoreturn)
 {
   tree fntype;
   tree fndecl;
@@ -244,6 +244,7 @@ m2decl_BuildEndFunctionDeclaration (location_t location_begin,
       = build_decl (location_end, RESULT_DECL, NULL_TREE, returntype);
   DECL_CONTEXT (DECL_RESULT (fndecl)) = fndecl;
   TREE_TYPE (fndecl) = fntype;
+  TREE_THIS_VOLATILE (fndecl) = isnoreturn;
 
   DECL_SOURCE_LOCATION (fndecl) = location_begin;
 
diff --git a/gcc/m2/gm2-gcc/m2decl.def b/gcc/m2/gm2-gcc/m2decl.def
index 036f903c..6a19693 100644
--- a/gcc/m2/gm2-gcc/m2decl.def
+++ b/gcc/m2/gm2-gcc/m2decl.def
@@ -149,7 +149,8 @@ PROCEDURE BuildStartFunctionDeclaration (uses_varargs: BOOLEAN) ;
 
 PROCEDURE BuildEndFunctionDeclaration (location_begin, location_end: location_t;
                                        name: ADDRESS; returntype: Tree;
-                                       isexternal, isnested, ispublic: BOOLEAN) : Tree ;
+                                       isexternal, isnested, ispublic,
+                                       isnoreturn: BOOLEAN) : Tree ;
 
 
 (*
diff --git a/gcc/m2/gm2-gcc/m2decl.h b/gcc/m2/gm2-gcc/m2decl.h
index 13ecaaf..19dbb7b 100644
--- a/gcc/m2/gm2-gcc/m2decl.h
+++ b/gcc/m2/gm2-gcc/m2decl.h
@@ -58,7 +58,8 @@ EXTERN void m2decl_RememberVariables (tree l);
 
 EXTERN tree m2decl_BuildEndFunctionDeclaration (
     location_t location_begin, location_t location_end, const char *name,
-    tree returntype, int isexternal, int isnested, int ispublic);
+    tree returntype, int isexternal, int isnested, int ispublic,
+    int isnoreturn);
 EXTERN void m2decl_BuildStartFunctionDeclaration (int uses_varargs);
 EXTERN tree m2decl_BuildParameterDeclaration (location_t location, char *name,
                                               tree type, int isreference);
diff --git a/gcc/m2/gm2-gcc/m2except.cc b/gcc/m2/gm2-gcc/m2except.cc
index 2f43b68..ab7df80 100644
--- a/gcc/m2/gm2-gcc/m2except.cc
+++ b/gcc/m2/gm2-gcc/m2except.cc
@@ -103,18 +103,19 @@ m2except_InitExceptions (location_t location)
 
   m2decl_BuildStartFunctionDeclaration (FALSE);
   fn_rethrow_tree = m2decl_BuildEndFunctionDeclaration (
-      location, location, "__cxa_rethrow", void_type_node, TRUE, FALSE, TRUE);
+     location, location, "__cxa_rethrow", void_type_node, TRUE, FALSE,
+     TRUE, FALSE);
   TREE_NOTHROW (fn_rethrow_tree) = 0;
 
   m2decl_BuildStartFunctionDeclaration (FALSE);
   m2decl_BuildParameterDeclaration (location, NULL, ptr_type_node, FALSE);
   fn_begin_catch_tree = m2decl_BuildEndFunctionDeclaration (
       location, location, "__cxa_begin_catch", ptr_type_node, TRUE, FALSE,
-      TRUE);
+      TRUE, FALSE);
   m2decl_BuildStartFunctionDeclaration (FALSE);
   fn_end_catch_tree = m2decl_BuildEndFunctionDeclaration (
       location, location, "__cxa_end_catch", void_type_node, TRUE, FALSE,
-      TRUE);
+      TRUE, FALSE);
   /* This can throw if the destructor for the exception throws.  */
   TREE_NOTHROW (fn_end_catch_tree) = 0;
 
@@ -130,26 +131,28 @@ m2except_InitExceptions (location_t location)
   m2decl_BuildParameterDeclaration (location, NULL, ptr_type_node, FALSE);
   m2decl_BuildParameterDeclaration (location, NULL, ptr_type_node, FALSE);
   fn_throw_tree = m2decl_BuildEndFunctionDeclaration (
-      location, location, "__cxa_throw", void_type_node, TRUE, FALSE, TRUE);
+      location, location, "__cxa_throw", void_type_node, TRUE, FALSE, TRUE,
+      FALSE);
 
   /* Declare void __cxa_rethrow (void).  */
   m2decl_BuildStartFunctionDeclaration (FALSE);
   fn_rethrow_tree = m2decl_BuildEndFunctionDeclaration (
-      location, location, "__cxa_rethrow", void_type_node, TRUE, FALSE, TRUE);
+     location, location, "__cxa_rethrow", void_type_node, TRUE, FALSE, TRUE,
+     FALSE);
 
   /* Declare void *__cxa_allocate_exception (size_t).  */
   m2decl_BuildStartFunctionDeclaration (FALSE);
   m2decl_BuildParameterDeclaration (location, NULL, size_type_node, FALSE);
   fn_allocate_exception_tree = m2decl_BuildEndFunctionDeclaration (
       location, location, "__cxa_allocate_exception", ptr_type_node, TRUE,
-      FALSE, TRUE);
+      FALSE, TRUE, FALSE);
 
   /* Declare void *__cxa_free_exception (void *).  */
   m2decl_BuildStartFunctionDeclaration (FALSE);
   m2decl_BuildParameterDeclaration (location, NULL, ptr_type_node, FALSE);
   fn_free_exception_tree = m2decl_BuildEndFunctionDeclaration (
       location, location, "__cxa_free_exception", ptr_type_node, TRUE, FALSE,
-      TRUE);
+      TRUE, FALSE);
 
   /* Define integer type exception type which will match C++ int type
      in the C++ runtime library.  */