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vm: fix integer overflow

db4
Slava Pestov 2009-10-09 05:53:55 -05:00
parent ab9b462411
commit 639a64c2df
2 changed files with 9 additions and 8 deletions
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3
vm/heap.cpp
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@ -13,8 +13,9 @@ void heap::clear_free_list()
heap::heap(bool secure_gc_, cell size) : secure_gc(secure_gc_) heap::heap(bool secure_gc_, cell size) : secure_gc(secure_gc_)
{ {
if(size > (1L << (sizeof(cell) * 8 - 6))) fatal_error("Heap too large",size);
seg = new segment(align_page(size)); seg = new segment(align_page(size));
if(!seg) fatal_error("Out of memory in new_heap",size); if(!seg) fatal_error("Out of memory in heap allocator",size);
clear_free_list(); clear_free_list();
} }

14
vm/layouts.hpp
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@ -64,9 +64,9 @@ inline static cell align8(cell a)
#define TYPE_COUNT 15 #define TYPE_COUNT 15
/* Not a real type, but code_block's type field can be set to this */ /* Not real types, but code_block's type can be set to this */
#define PIC_TYPE 42 #define PIC_TYPE 16
#define FREE_BLOCK_TYPE 69 #define FREE_BLOCK_TYPE 17
/* Constants used when floating-point trap exceptions are thrown */ /* Constants used when floating-point trap exceptions are thrown */
enum enum
@ -213,16 +213,16 @@ struct heap_block
header &= ~1; header &= ~1;
} }
cell type() { return (header >> 1) & 0x7f; } cell type() { return (header >> 1) & 0x1f; }
void set_type(cell type) void set_type(cell type)
{ {
header = ((header & ~(0x7f << 1)) | (type << 1)); header = ((header & ~(0x1f << 1)) | (type << 1));
} }
cell size() { return (header >> 8); } cell size() { return (header >> 6); }
void set_size(cell size) void set_size(cell size)
{ {
header = (header & 0xff) | (size << 8); header = (header & 0x2f) | (size << 6);
} }
}; };