New subject: GPC source code errors

9 Mar 2016

Gale Paeper wrote:
...
While trying to get a successful compilation of GPC on Mac OS X 10.11 using AppleĂ˘ÂÂs LLVM based tool chain, I discovered what looks to be a couple of source code errors in p/statements.c in the expand_pascal_assignment2 functionĂ˘ÂÂs code.  That function is declared with a void return type so there shouldnĂ˘ÂÂt be any return statements returning a value anywhere within the body of the function but there are two uses of the CHK_EM macro which does expand to a return statement that potentially returns a value (a tree type). Trying to potentially return something into the void of a non-existant return isnĂ˘ÂÂt technically correct code and I havenĂ˘ÂÂt found a way to get the LLVM based clang compiler to accept it.
IĂ˘ÂÂll note that you can get a gnu gcc version 5.2.0 compiler to accept the code when compiling with the -std=gnu89 command line option.
The GPC source code version IĂ˘ÂÂm trying to get compiling is the Adriaan van OsĂ˘ÂÂs Mac OS X patched gcc 3.4.6 with the p directory replaced with Waldek HebischĂ˘ÂÂs git repositoryĂ˘ÂÂs (https://github.com/hebisch/gpc) p directory source code. The code fragment containing the error producing code starting around line 1231 in file p/statements.c (in expand_pascal_assignment2 functionĂ˘ÂÂs body) is:
schema_source = undo_schema_dereference (source);
  schema_target = undo_schema_dereference (target);
  DEREFERENCE_SCHEMA (source);
  DEREFERENCE_SCHEMA (target);
  CHK_EM (source);
  CHK_EM (target);
The patch below should fix this:

diff --git a/p/statements.c b/p/statements.c
index 4904834..e0026b7 100644
--- a/p/statements.c
+++ b/p/statements.c
@@ -1232,8 +1232,8 @@ expand_pascal_assignment2 (tree target, tree source, int is_init)
   schema_target = undo_schema_dereference (target);
   DEREFERENCE_SCHEMA (source);
   DEREFERENCE_SCHEMA (target);
-  CHK_EM (source);
-  CHK_EM (target);
+  if (EM (source)||EM (target))
+    return;
/* Restricted types. @@@@ Maybe this needs further checking */
   if (TREE_CODE (source) == CALL_EXPR && PASCAL_TYPE_RESTRICTED (TREE_TYPE (source)))
-- 
                              Waldek Hebisch


    

Re: GPC source code errors