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py2llvm: support for try/except/else/finally blocks

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This commit is contained in:
Sebastien Bourdeauducq 2014-09-23 16:23:54 +08:00
parent 0a02d9fb78
commit d1085449aa
1 changed files with 75 additions and 2 deletions
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77
artiq/py2llvm/ast_body.py
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@ -1,4 +1,5 @@
import ast
from llvm import core as lc
from artiq.py2llvm import values, base_types, fractions, arrays, iterators
from artiq.py2llvm.tools import is_terminated
@ -42,6 +43,7 @@ class Visitor:
self.ns = ns
self.builder = builder
self._break_stack = []
self._eid_stack = []
# builder can be None for visit_expression
def visit_expression(self, node):
@ -278,5 +280,76 @@ class Visitor:
pass
def _visit_stmt_Raise(self, node):
eid = node.exc.args[0].n
self.env.build_raise(eid, self.builder)
if node.exc is None:
eid = self._eid_stack[-1]
else:
eid = lc.Constant.int(lc.Type.int(), node.exc.args[0].n)
self.env.build_raise(self.builder, eid)
def _handle_exception(self, function, finally_block, propagate, handlers):
eid = self.env.build_getid(self.builder)
self._eid_stack.append(eid)
self.builder.store(lc.Constant.int(lc.Type.int(1), 1), propagate)
for handler in handlers:
handled_exc_block = function.append_basic_block("try_exc_h")
cont_exc_block = function.append_basic_block("try_exc_c")
if handler.type is None:
self.builder.branch(handled_exc_block)
else:
if isinstance(handler.type, ast.Tuple):
match = self.builder.icmp(
lc.ICMP_EQ, eid, handler.type.elts[0].args[0].n)
for elt in handler.type.elts[1:]:
match = self.builder.or_(
match,
self.builder.icmp(lc.ICMP_EQ, eid, elt.args[0].n))
else:
match = self.builder.icmp(
lc.ICMP_EQ, eid, handler.type.args[0].n)
self.builder.cbranch(match, handled_exc_block, cont_exc_block)
self.builder.position_at_end(handled_exc_block)
self.builder.store(lc.Constant.int(lc.Type.int(1), 0), propagate)
self.visit_statements(handler.body)
if not is_terminated(self.builder.basic_block):
self.builder.branch(finally_block)
self.builder.position_at_end(cont_exc_block)
self.builder.branch(finally_block)
self._eid_stack.pop()
return eid
def _visit_stmt_Try(self, node):
function = self.builder.basic_block.function
noexc_block = function.append_basic_block("try_noexc")
exc_block = function.append_basic_block("try_exc")
finally_block = function.append_basic_block("try_finally")
propagate = self.builder.alloca(lc.Type.int(1), name="propagate")
self.builder.store(lc.Constant.int(lc.Type.int(1), 0), propagate)
exception_occured = self.env.build_catch(self.builder)
self.builder.cbranch(exception_occured, exc_block, noexc_block)
self.builder.position_at_end(noexc_block)
self.visit_statements(node.body)
if not is_terminated(self.builder.basic_block):
self.env.build_pop(self.builder, 1)
self.visit_statements(node.orelse)
if not is_terminated(self.builder.basic_block):
self.builder.branch(finally_block)
self.builder.position_at_end(exc_block)
eid = self._handle_exception(function, finally_block, propagate,
node.handlers)
propagate_block = function.append_basic_block("try_propagate")
merge_block = function.append_basic_block("try_merge")
self.builder.position_at_end(finally_block)
self.visit_statements(node.finalbody)
if not is_terminated(self.builder.basic_block):
self.builder.cbranch(
self.builder.load(propagate),
propagate_block, merge_block)
self.builder.position_at_end(propagate_block)
self.env.build_raise(self.builder, eid)
self.builder.branch(merge_block)
self.builder.position_at_end(merge_block)