kernel: change pcp collector to use their own stacks

... instead of using the stack objects in the pcp collector objects provided
by the polycyclic package. This will make it possible to remove the latter in
a future version of polycyclic, thus reducing the size of these objects
considerably.

Author: fingolfin

src/objcftl.c

@@ -19,12 +19,28 @@
 
 #include "ariths.h"
 #include "error.h"
+#include "gapstate.h"
 #include "gvars.h"
 #include "integer.h"
 #include "modules.h"
 #include "plist.h"
 
 
+static ModuleStateOffset CFTLStateOffset = -1;
+
+struct CFTLModuleState {
+    Obj WORD_STACK;
+    Obj WORD_EXPONENT_STACK;
+    Obj SYLLABLE_STACK;
+    Obj EXPONENT_STACK;
+};
+
+extern inline struct CFTLModuleState *CFTLState(void)
+{
+    return (struct CFTLModuleState *)StateSlotsAtOffset(CFTLStateOffset);
+}
+
+
 #define IS_INT_ZERO( n )  ((n) == INTOBJ_INT(0))
 
 #define GET_COMMUTE( g )  INT_INTOBJ(ELM_PLIST(commute,(g))) 
@@ -87,14 +103,14 @@ Obj CollectPolycyc (
     Obj    ipow    = ADDR_OBJ(pcp)[ PC_INVERSEPOWERS ];
     Obj    exp     = ADDR_OBJ(pcp)[ PC_EXPONENTS ];
 
-    Obj    wst  = ADDR_OBJ(pcp)[ PC_WORD_STACK ];
-    Obj    west = ADDR_OBJ(pcp)[ PC_WORD_EXPONENT_STACK ];
-    Obj    sst  = ADDR_OBJ(pcp)[ PC_SYLLABLE_STACK ];
-    Obj    est  = ADDR_OBJ(pcp)[ PC_EXPONENT_STACK ];
+    Obj    wst  = CFTLState()->WORD_STACK;
+    Obj    west = CFTLState()->WORD_EXPONENT_STACK;
+    Obj    sst  = CFTLState()->SYLLABLE_STACK;
+    Obj    est  = CFTLState()->EXPONENT_STACK;
 
     Obj    conj=0, iconj=0;   /*QQ initialize to please compiler */
 
-    Int    st, bottom = INT_INTOBJ( ADDR_OBJ(pcp)[ PC_STACK_POINTER ] );
+    Int    st, bottom = 0;
 
     Int    g, syl, h, hh;
 
@@ -296,7 +312,6 @@ Obj CollectPolycyc (
       }
     }
 
-    ADDR_OBJ(pcp)[ PC_STACK_POINTER ] = INTOBJ_INT( bottom );
     return (Obj)0;
 }
 
@@ -394,6 +409,13 @@ static Int InitLibrary (
     return 0;
 }
 
+static void InitModuleState(ModuleStateOffset offset)
+{
+    CFTLState()->WORD_STACK  = NEW_PLIST( T_PLIST, 4096 );
+    CFTLState()->WORD_EXPONENT_STACK = NEW_PLIST( T_PLIST, 4096 );
+    CFTLState()->SYLLABLE_STACK = NEW_PLIST( T_PLIST, 4096 );
+    CFTLState()->EXPONENT_STACK = NEW_PLIST( T_PLIST, 4096 );
+}
 
 /****************************************************************************
 **
@@ -411,5 +433,6 @@ static StructInitInfo module = {
 
 StructInitInfo * InitInfoPcc ( void )
 {
+    CFTLStateOffset = RegisterModuleState(sizeof(struct CFTLModuleState), InitModuleState, 0);
     return &module;
 }

src/objcftl.h

@@ -27,14 +27,35 @@
 #define PC_DEEP_THOUGHT_BOUND       13
 #define PC_ORDERS                   14
 
+// TODO: the following stack related positions are not
+// used anymore by CollectPolycyc, and will not be used
+// anymore in future releases of the polycyclic package.
+// We should phase them out for GAP 4.10.
 #define PC_WORD_STACK               15
 #define PC_STACK_SIZE               16
 #define PC_WORD_EXPONENT_STACK      17
 #define PC_SYLLABLE_STACK           18
 #define PC_EXPONENT_STACK           19
 #define PC_STACK_POINTER            20
+// TODO: end obsolete
+
 #define PC_DEFAULT_TYPE             21
 
+/* the following are defined in polycyclic:
+
+#define PC_PCP_ELEMENTS_FAMILY          22
+#define PC_PCP_ELEMENTS_TYPE            23
+
+#define PC_COMMUTATORS                  24
+#define PC_INVERSECOMMUTATORS           25
+#define PC_COMMUTATORSINVERSE           26
+#define PC_INVERSECOMMUTATORSINVERSE    27
+
+#define PC_NILPOTENT_COMMUTE            28
+#define PC_WEIGHTS                      29
+#define PC_ABELIAN_START                30
+*/
+
 /****************************************************************************
 **
 *F * * * * * * * * * * * * * initialize module * * * * * * * * * * * * * * *