Change arena end ptr (#1177)

* arena_end_ptr() now returns char *; changes percolated through
collector
* young_alloc_ptr() and old_alloc_ptr() inlined
* evacuate() made a member function of class arena

Author: stevenmeker

include/runtime/arena.h

@@ -22,6 +22,8 @@ class arena {
     initialize_semispace();
   }
 
+  char *evacuate(char *scan_ptr);
+
   // Allocates the requested number of bytes as a contiguous region and returns a
   // pointer to the first allocated byte.
   void *kore_arena_alloc(size_t requested);
@@ -33,7 +35,7 @@ class arena {
   // Returns a pointer to a location holding the address of last allocated
   // byte in the given arena plus 1.
   // This address is nullptr if nothing has been allocated ever in that arena.
-  char **arena_end_ptr() { return &allocation_ptr; }
+  char *arena_end_ptr() { return allocation_ptr; }
 
   // Clears the current allocation space by setting its start back to its first
   // block. It is used during garbage collection to effectively collect all of the
@@ -73,9 +75,9 @@ class arena {
   // 3rd argument: the address of last allocated byte in the arena plus 1
   // Return value: starting pointer + size unless this points to unallocated space
   //               in which case nullptr is returned
-  static char *move_ptr(char *ptr, size_t size, char const *arena_end_ptr) {
+  static char *move_ptr(char *ptr, size_t size, char const *end_ptr) {
     char *next_ptr = ptr + size;
-    return (next_ptr == arena_end_ptr) ? nullptr : next_ptr;
+    return (next_ptr == end_ptr) ? nullptr : next_ptr;
   }
 
   // Returns the ID of the semispace where the given address was allocated.
@@ -132,7 +134,7 @@ inline char arena::get_arena_semispace_id_of_object(void *ptr) {
 
 // Macro to define a new arena with the given ID. Supports IDs ranging from 0 to
 // 127.
-#define REGISTER_ARENA(name, id) static thread_local arena name(id)
+#define REGISTER_ARENA(name, id) thread_local arena name(id)
 
 #ifdef __MACH__
 //

runtime/alloc/arena.cpp

@@ -7,6 +7,7 @@
 
 #include "runtime/alloc.h"
 #include "runtime/arena.h"
+#include "runtime/collect.h"
 #include "runtime/header.h"
 
 extern size_t const VAR_BLOCK_SIZE = BLOCK_SIZE;

runtime/collect/collect.cpp

@@ -10,9 +10,9 @@
 #include <cstring>
 
 extern "C" {
+extern thread_local arena youngspace;
+extern thread_local arena oldspace;
 
-char **young_alloc_ptr(void);
-char **old_alloc_ptr(void);
 char *youngspace_ptr(void);
 char *oldspace_ptr(void);
 
@@ -245,7 +245,7 @@ static void migrate_root(void *curr_block, layoutitem *args, unsigned i) {
   }
 }
 
-static char *evacuate(char *scan_ptr, char **alloc_ptr) {
+char *arena::evacuate(char *scan_ptr) {
   auto *curr_block = (block *)scan_ptr;
   uint64_t const hdr = curr_block->h.hdr;
   uint16_t layout_int = layout_hdr(hdr);
@@ -255,7 +255,7 @@ static char *evacuate(char *scan_ptr, char **alloc_ptr) {
       migrate_child(curr_block, layout_data->args, i, false);
     }
   }
-  return arena::move_ptr(scan_ptr, get_size(hdr, layout_int), *alloc_ptr);
+  return move_ptr(scan_ptr, get_size(hdr, layout_int), arena_end_ptr());
 }
 
 // Contains the decision logic for collecting the old generation.
@@ -293,43 +293,43 @@ void kore_collect(
   if (!last_alloc_ptr) {
     last_alloc_ptr = youngspace_ptr();
   }
-  char *current_alloc_ptr = *young_alloc_ptr();
+  char *current_alloc_ptr = youngspace.arena_end_ptr();
 #endif
   kore_alloc_swap(collect_old);
 #ifdef GC_DBG
   for (int i = 0; i < 2048; i++) {
     numBytesLiveAtCollection[i] = 0;
   }
 #endif
-  char *previous_oldspace_alloc_ptr = *old_alloc_ptr();
+  char *previous_oldspace_alloc_ptr = oldspace.arena_end_ptr();
   for (int i = 0; i < nroots; i++) {
     migrate_root(roots, type_info, i);
   }
   migrate_static_roots();
   char *scan_ptr = youngspace_ptr();
-  if (scan_ptr != *young_alloc_ptr()) {
+  if (scan_ptr != youngspace.arena_end_ptr()) {
     MEM_LOG("Evacuating young generation\n");
     while (scan_ptr) {
-      scan_ptr = evacuate(scan_ptr, young_alloc_ptr());
+      scan_ptr = youngspace.evacuate(scan_ptr);
     }
   }
   if (collect_old || !previous_oldspace_alloc_ptr) {
     scan_ptr = oldspace_ptr();
   } else {
     scan_ptr = previous_oldspace_alloc_ptr;
   }
-  if (scan_ptr != *old_alloc_ptr()) {
+  if (scan_ptr != oldspace.arena_end_ptr()) {
     MEM_LOG("Evacuating old generation\n");
     while (scan_ptr) {
-      scan_ptr = evacuate(scan_ptr, old_alloc_ptr());
+      scan_ptr = oldspace.evacuate(scan_ptr);
     }
   }
 #ifdef GC_DBG
   ssize_t numBytesAllocedSinceLastCollection
       = arena::ptr_diff(current_alloc_ptr, last_alloc_ptr);
   assert(numBytesAllocedSinceLastCollection >= 0);
   fwrite(&numBytesAllocedSinceLastCollection, sizeof(ssize_t), 1, stderr);
-  last_alloc_ptr = *young_alloc_ptr();
+  last_alloc_ptr = youngspace.arena_end_ptr();
   fwrite(
       numBytesLiveAtCollection, sizeof(numBytesLiveAtCollection[0]),
       sizeof(numBytesLiveAtCollection) / sizeof(numBytesLiveAtCollection[0]),

runtime/lto/alloc.cpp

@@ -23,14 +23,6 @@ char *oldspace_ptr() {
   return oldspace.arena_start_ptr();
 }
 
-char **young_alloc_ptr() {
-  return youngspace.arena_end_ptr();
-}
-
-char **old_alloc_ptr() {
-  return oldspace.arena_end_ptr();
-}
-
 char youngspace_collection_id() {
   return youngspace.get_arena_collection_semispace_id();
 }
@@ -81,7 +73,7 @@ kore_resize_last_alloc(void *oldptr, size_t newrequest, size_t last_size) {
   newrequest = (newrequest + 7) & ~7;
   last_size = (last_size + 7) & ~7;
 
-  if (oldptr != *(youngspace.arena_end_ptr()) - last_size) {
+  if (oldptr != youngspace.arena_end_ptr() - last_size) {
     MEM_LOG(
         "May only reallocate last allocation. Tried to reallocate %p to %zd\n",
         oldptr, newrequest);