+/* -----------------------------------------------------------------------------
+ Macros for distinguishing data pointers from code pointers
+ -------------------------------------------------------------------------- */
+/*
+ * We use some symbols inserted automatically by the linker to decide
+ * whether a pointer points to text, data, or user space. These tests
+ * assume that text is lower in the address space than data, which in
+ * turn is lower than user allocated memory.
+ *
+ * If this assumption is false (say on some strange architecture) then
+ * the tests IS_CODE_PTR and IS_DATA_PTR below will need to be
+ * modified (and that should be all that's necessary).
+ *
+ * _start } start of read-only text space
+ * _etext } end of read-only text space
+ * _end } end of read-write data space
+ */
+extern StgFun start;
+
+extern void* TEXT_SECTION_END_MARKER_DECL;
+extern void* DATA_SECTION_END_MARKER_DECL;
+
+#if defined(INTERPRETER) || defined(GHCI)
+/* Take into account code sections in dynamically loaded object files. */
+#define IS_CODE_PTR(p) ( ((P_)(p) < (P_)&TEXT_SECTION_END_MARKER) \
+ || is_dynamically_loaded_code_or_rodata_ptr((char *)p) )
+#define IS_DATA_PTR(p) ( ((P_)(p) >= (P_)&TEXT_SECTION_END_MARKER && \
+ (P_)(p) < (P_)&DATA_SECTION_END_MARKER) \
+ || is_dynamically_loaded_rwdata_ptr((char *)p) )
+#define IS_USER_PTR(p) ( ((P_)(p) >= (P_)&DATA_SECTION_END_MARKER) \
+ && is_not_dynamically_loaded_ptr((char *)p) )
+#else
+#define IS_CODE_PTR(p) ((P_)(p) < (P_)&TEXT_SECTION_END_MARKER)
+#define IS_DATA_PTR(p) ((P_)(p) >= (P_)&TEXT_SECTION_END_MARKER && (P_)(p) < (P_)&DATA_SECTION_END_MARKER)
+#define IS_USER_PTR(p) ((P_)(p) >= (P_)&DATA_SECTION_END_MARKER)
+#endif
+
+/* The HEAP_ALLOCED test below is called FOR EVERY SINGLE CLOSURE
+ * during GC. It needs to be FAST.
+ */
+#ifdef TEXT_BEFORE_HEAP
+# define HEAP_ALLOCED(x) ((StgPtr)(x) >= (StgPtr)(HEAP_BASE))
+#else
+extern int is_heap_alloced(const void* x);
+# define HEAP_ALLOCED(x) (is_heap_alloced(x))
+#endif
+
+/* When working with Win32 DLLs, static closures are identified by
+ being prefixed with a zero word. This is needed so that we can
+ distinguish between pointers to static closures and (reversed!)
+ info tables.
+
+ This 'scheme' breaks down for closure tables such as CHARLIKE,
+ so we catch these separately.
+
+ LOOKS_LIKE_STATIC_CLOSURE()
+ - discriminates between static closures and info tbls
+ (needed by LOOKS_LIKE_GHC_INFO() below - [Win32 DLLs only.])
+ LOOKS_LIKE_STATIC()
+ - distinguishes between static and heap allocated data.
+ */
+#if defined(ENABLE_WIN32_DLL_SUPPORT) && !defined(INTERPRETER)
+ /* definitely do not enable for mingw DietHEP */
+#define LOOKS_LIKE_STATIC(r) (!(HEAP_ALLOCED(r)))
+
+/* Tiresome predicates needed to check for pointers into the closure tables */
+#define IS_CHARLIKE_CLOSURE(p) \
+ ( (P_)(p) >= (P_)stg_CHARLIKE_closure && \
+ (char*)(p) <= ((char*)stg_CHARLIKE_closure + \
+ (MAX_CHARLIKE-MIN_CHARLIKE) * sizeof(StgIntCharlikeClosure)) )
+#define IS_INTLIKE_CLOSURE(p) \
+ ( (P_)(p) >= (P_)stg_INTLIKE_closure && \
+ (char*)(p) <= ((char*)stg_INTLIKE_closure + \
+ (MAX_INTLIKE-MIN_INTLIKE) * sizeof(StgIntCharlikeClosure)) )
+
+#define LOOKS_LIKE_STATIC_CLOSURE(r) (((*(((unsigned long *)(r))-1)) == 0) || IS_CHARLIKE_CLOSURE(r) || IS_INTLIKE_CLOSURE(r))
+#else
+#define LOOKS_LIKE_STATIC(r) IS_DATA_PTR(r)
+#define LOOKS_LIKE_STATIC_CLOSURE(r) IS_DATA_PTR(r)
+#endif
+
+
+/* -----------------------------------------------------------------------------
+ Macros for distinguishing infotables from closures.
+
+ You'd think it'd be easy to tell an info pointer from a closure pointer:
+ closures live on the heap and infotables are in read only memory. Right?
+ Wrong! Static closures live in read only memory and Hugs allocates
+ infotables for constructors on the (writable) C heap.
+ -------------------------------------------------------------------------- */
+
+#ifdef INTERPRETER
+# ifdef USE_MINIINTERPRETER
+ /* yoiks: one of the dreaded pointer equality tests */
+# define IS_HUGS_CONSTR_INFO(info) \
+ (((StgInfoTable *)(info))->entry == (StgFunPtr)&Hugs_CONSTR_entry)
+# else
+# define IS_HUGS_CONSTR_INFO(info) 0 /* ToDo: more than mildly bogus */
+# endif
+#elif GHCI
+ /* not accurate by any means, but stops the assertions failing... */
+# define IS_HUGS_CONSTR_INFO(info) IS_USER_PTR(info)
+#else
+# define IS_HUGS_CONSTR_INFO(info) 0 /* ToDo: more than mildly bogus */
+#endif
+
+/* LOOKS_LIKE_GHC_INFO is called moderately often during GC, but
+ * Certainly not as often as HEAP_ALLOCED.
+ */
+#ifdef TEXT_BEFORE_HEAP /* needed for mingw DietHEP */
+# define LOOKS_LIKE_GHC_INFO(info) IS_CODE_PTR(info)
+#else
+# define LOOKS_LIKE_GHC_INFO(info) (!HEAP_ALLOCED(info) \
+ && !LOOKS_LIKE_STATIC_CLOSURE(info))
+#endif
+
+/* -----------------------------------------------------------------------------
+ Macros for calculating how big a closure will be (used during allocation)
+ -------------------------------------------------------------------------- */
+
+/* ToDo: replace unsigned int by nat. The only fly in the ointment is that
+ * nat comes from Rts.h which many folk dont include. Sigh!
+ */
+static __inline__ StgOffset AP_sizeW ( unsigned int n_args )
+{ return sizeofW(StgAP_UPD) + n_args; }
+
+static __inline__ StgOffset PAP_sizeW ( unsigned int n_args )
+{ return sizeofW(StgPAP) + n_args; }
+
+static __inline__ StgOffset CONSTR_sizeW( unsigned int p, unsigned int np )
+{ return sizeofW(StgHeader) + p + np; }
+
+static __inline__ StgOffset BCO_sizeW ( unsigned int p, unsigned int np, unsigned int is )
+{ return sizeofW(StgBCO) + p + np + (is+sizeof(StgWord)-1)/sizeof(StgWord); }
+
+static __inline__ StgOffset THUNK_SELECTOR_sizeW ( void )
+{ return sizeofW(StgHeader) + MIN_UPD_SIZE; }
+
+static __inline__ StgOffset BLACKHOLE_sizeW ( void )
+{ return sizeofW(StgHeader) + MIN_UPD_SIZE; }
+
+static __inline__ StgOffset CAF_sizeW ( void )
+{ return sizeofW(StgCAF); }
+
+/* --------------------------------------------------------------------------
+ * Sizes of closures
+ * ------------------------------------------------------------------------*/
+
+static __inline__ StgOffset sizeW_fromITBL( const StgInfoTable* itbl )
+{ return sizeofW(StgClosure)
+ + sizeofW(StgPtr) * itbl->layout.payload.ptrs
+ + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
+
+static __inline__ StgOffset pap_sizeW( StgPAP* x )
+{ return PAP_sizeW(x->n_args); }
+
+static __inline__ StgOffset arr_words_sizeW( StgArrWords* x )
+{ return sizeofW(StgArrWords) + x->words; }
+
+static __inline__ StgOffset mut_arr_ptrs_sizeW( StgMutArrPtrs* x )
+{ return sizeofW(StgMutArrPtrs) + x->ptrs; }
+
+static __inline__ StgWord tso_sizeW ( StgTSO *tso )
+{ return TSO_STRUCT_SIZEW + tso->stack_size; }
+