factor/vm/code_blocks.hpp

154 lines
3.2 KiB
C++

namespace factor
{
/* The compiled code heap is structured into blocks. */
struct code_block
{
// header format (bits indexed with least significant as zero):
// bit 0 : free?
// bits 1-2: type (as a code_block_type)
// if not free:
// bits 3-23: code size / 8
// bits 24-31: stack frame size / 16
// if free:
// bits 3-end: code size / 8
cell header;
cell owner; /* tagged pointer to word, quotation or f */
cell parameters; /* tagged pointer to array or f */
cell relocation; /* tagged pointer to byte-array or f */
bool free_p() const
{
return (header & 1) == 1;
}
code_block_type type() const
{
return (code_block_type)((header >> 1) & 0x3);
}
void set_type(code_block_type type)
{
header = ((header & ~0x7) | (type << 1));
}
bool pic_p() const
{
return type() == code_block_pic;
}
bool optimized_p() const
{
return type() == code_block_optimized;
}
cell size() const
{
cell size;
if (free_p())
size = header & ~7;
else
size = header & 0xFFFFF8;
FACTOR_ASSERT(size > 0);
return size;
}
cell stack_frame_size() const
{
if (free_p())
return 0;
else
return (header >> 20) & 0xFF0;
}
cell stack_frame_size_for_address(cell addr) const
{
cell natural_frame_size = stack_frame_size();
/* The first instruction in a code block is the prolog safepoint,
and a leaf procedure code block will record a frame size of zero.
If we're seeing a stack frame in either of these cases, it's a
fake "leaf frame" set up by the signal handler. */
if (natural_frame_size == 0 || (void*)addr == entry_point())
return LEAF_FRAME_SIZE;
else
return natural_frame_size;
}
void set_stack_frame_size(cell frame_size)
{
FACTOR_ASSERT(size() < 0xFFFFFF);
FACTOR_ASSERT(!free_p());
FACTOR_ASSERT(frame_size % 16 == 0);
FACTOR_ASSERT(frame_size <= 0xFF0);
header = (header & 0xFFFFFF) | (frame_size << 20);
}
template<typename Fixup> cell size(Fixup fixup) const
{
return size();
}
void *entry_point() const
{
return (void *)(this + 1);
}
/* GC info is stored at the end of the block */
gc_info *block_gc_info() const
{
return (gc_info *)((u8 *)this + size() - sizeof(gc_info));
}
void flush_icache()
{
factor::flush_icache((cell)this,size());
}
template<typename Iterator> void each_instruction_operand(Iterator &iter)
{
if(to_boolean(relocation))
{
byte_array *rels = (byte_array *)UNTAG(relocation);
cell index = 0;
cell length = (rels->capacity >> TAG_BITS) / sizeof(relocation_entry);
for(cell i = 0; i < length; i++)
{
relocation_entry rel = rels->data<relocation_entry>()[i];
iter(instruction_operand(rel,this,index));
index += rel.number_of_parameters();
}
}
}
cell offset(void *addr) const
{
return (char*)addr - (char*)entry_point();
}
void *address_for_offset(cell offset) const
{
return (void*)((char*)entry_point() + offset);
}
cell scan(factor_vm *vm, void *addr) const;
cell owner_quot() const;
};
VM_C_API void undefined_symbol(void);
inline code_block *word::code() const {
FACTOR_ASSERT(entry_point != NULL);
return (code_block*)entry_point - 1;
}
inline code_block *quotation::code() const {
FACTOR_ASSERT(entry_point != NULL);
return (code_block*)entry_point - 1;
}
}