def Func(self, name, main=False):
"""Generates x86 code for the function given by name. This is the entry
point for all code generation."""
## Get the function.
func = self.functions[name]
self.cfunc = func
## Generate a label for the function
self.code += [x.label(name)]
## If this is not the `main` function generate a stack push
if not main:
self.code += self.FramePush(len(func.params), func.scope_depth)
## Move the stack pointer down. This creates the stack frame.
syms = self.gather_syms(func.blks)
sp_offset = self.place_symbols(syms, func)
self.code += [x.subl(x.cint(sp_offset * 4), x.esp)]
def block(insts):
"""Generate the x86 instruction for the given block of instructions.
"""
## We could do something more clever than switch case here, but I
## (for now) perfer the simplicity.
for i in insts:
if i.op == il.PRNT:
self.code += self.Print(i)
elif i.op == il.IMM:
self.code += self.Imm(i)
elif i.op == il.GPRM:
self.code += self.Gprm(i)
elif i.op == il.IPRM:
self.code += self.Iprm(i)
elif i.op == il.OPRM:
## OPRMs always appear directly before RTRN instructions.
## Based on the way the stack frame pop is generated the pop
## must be generated before the OPRM instruction. So the
## output params can be properly returned.
if not main and func.oparam_count > 0:
self.code += self.FramePop(len(func.params), func.scope_depth)
if func.oparam_count == 0:
raise Exception, "expected no return paramters got at least 1."
self.code += self.Oprm(i)
elif i.op == il.RPRM:
self.code += self.Rprm(i)
elif i.op == il.CALL:
self.code += self.Call(i)
elif i.op == il.RTRN:
if not main and func.oparam_count == 0:
self.code += self.FramePop(len(func.params), func.scope_depth)
self.code += self.Return(i)
elif i.op == il.MV:
self.code += self.Mv(i)
elif i.op in [il.ADD, il.SUB, il.MUL, il.DIV]:
self.code += self.Op(i)
elif i.op in [il.IFEQ, il.IFNE, il.IFLT, il.IFLE, il.IFGT, il.IFGE]:
self.code += self.BranchOp(i)
elif i.op == il.J:
self.code += self.J(i)
elif i.op == il.NOP:
self.code += self.Nop(i)
else:
raise Exception, il.opsr[i.op]
## generate a label for the entry block of the function.
self.code += [x.label(func.entry.name)]
block(self.blocks[func.entry.name].insts) # generate the function.
## for each block in the function (excluding entry and exit) generate
## the code.
for b in func.blks:
if b.name == func.entry.name:
continue
if b.name == func.exit.name:
continue
self.code += [x.label(b.name)]
self.code += [x.nop()]
block(self.blocks[b.name].insts)
## If there a distinct exit block, generate it.
if func.entry.name != func.exit.name:
self.code += [x.label(func.exit.name)]
b = func.exit
self.code += [x.nop()]
block(self.blocks[b.name].insts)
def Nop(self, i):
code = [x.nop()]
return code
def Func(self, name, main=False):
#print name
self.code += [
x.label(name)
]
#print '->', insts
func = self.functions[name]
self.cfunc = func
#insts = self.blocks[func.entry.name].insts
self.bp_offset = 3
if not main:
self.code += self.FramePush(len(func.params), func.scope_depth)
syms = self.gather_syms(func.blks)
#print syms
fp_offset = self.place_symbols(syms, func)
#print name, 'fp_offset', fp_offset
self.code += [
x.subl(x.cint(fp_offset*4), x.esp)
#(vm.IMM, 4, fp_offset, 'start func %s' % (name)),
#(vm.ADD, 1, 4, 'fp offset add inst'),
]
def block(insts):
for i in insts:
if i.op == il.PRNT:
self.code += self.Print(i)
elif i.op == il.IMM:
self.code += self.Imm(i)
elif i.op == il.GPRM:
self.code += self.Gprm(i)
elif i.op == il.IPRM:
self.code += self.Iprm(i)
elif i.op == il.OPRM:
if not main and func.oparam_count > 0:
self.code += self.FramePop(len(func.params), func.scope_depth)
if func.oparam_count == 0:
raise Exception, "expected no return paramters got at least 1."
self.code += self.Oprm(i)
elif i.op == il.RPRM:
self.code += self.Rprm(i)
elif i.op == il.CALL:
self.code += self.Call(i)
elif i.op == il.RTRN:
if not main and func.oparam_count == 0:
self.code += self.FramePop(len(func.params), func.scope_depth)
self.code += self.Return(i)
elif i.op == il.MV:
self.code += self.Mv(i)
elif i.op in [il.ADD, il.SUB, il.MUL, il.DIV]:
self.code += self.Op(i)
elif i.op in [il.IFEQ, il.IFNE, il.IFLT, il.IFLE, il.IFGT, il.IFGE]:
self.code += self.BranchOp(i)
elif i.op == il.J:
self.code += self.J(i)
elif i.op == il.NOP:
self.code += self.Nop(i)
else:
raise Exception, il.opsr[i.op]
#if i.label is not None:
#print code[l]
#code[l] = (code[l][0], code[l][1], code[l][2], i.label)
self.code += [ x.label(func.entry.name) ]
block(self.blocks[func.entry.name].insts)
for b in func.blks:
if b.name == func.entry.name: continue
if b.name == func.exit.name: continue
self.code += [ x.label(b.name) ]
self.floc[b.name] = len(self.code)
self.code += [ x.nop() ]
block(self.blocks[b.name].insts)
if func.entry.name != func.exit.name:
self.code += [ x.label(func.exit.name) ]
b = func.exit
self.floc[b.name] = len(self.code)
self.code += [ x.nop() ]
block(self.blocks[b.name].insts)
