def Canonicalize(ast: c_ast.FileAST, meta_info: meta.MetaInfo,
skip_constant_casts):
global_id_gen = common.UniqueId()
for node in ast:
if isinstance(node, c_ast.FuncDef):
CanonicalizeFun(node, meta_info)
meta_info.CheckConsistency(ast)
transform_arrayref.ConvertConvertAddressTakenScalarsToArray(ast, meta_info)
meta_info.CheckConsistency(ast)
transform_arrayref.ConvertArrayIndexToPointerDereference(ast, meta_info)
transform_arrayref.SimplifyAddressExpressions(ast, meta_info)
meta_info.CheckConsistency(ast)
ConvertCompoundAssignment(ast, meta_info, global_id_gen)
# This should go last so that we do not have worry to mess this
# up in other phases.
AddExplicitCasts(ast, ast, meta_info, skip_constant_casts)
transform_rename.LiftStaticAndExternToGlobalScope(ast, meta_info,
global_id_gen)
meta_info.CheckConsistency(ast)
ConfirmAbsenceOfUnsupportedFeatures(ast, ast)
def ConvertConvertAddressTakenScalarsToArray(ast, meta_info: meta.MetaInfo):
"""
Rewrite address taken scalar vars as one element arrays
After this transform we can keep all scalars in registers.
"""
def IsAddressTakenScalarOrGlobalScalar(node, parent):
if isinstance(node, c_ast.Decl) and IsScalarType(node.type):
# return isinstance(parent, c_ast.FileAST)
return (isinstance(parent, c_ast.FileAST) or
"static" in node.storage)
if not isinstance(node, c_ast.UnaryOp): return False
if node.op != "&": return False
if not isinstance(node.expr, c_ast.ID): return False
type = meta_info.type_links[node.expr]
return IsScalarType(type)
candidates = common.FindMatchingNodesPreOrder(ast, ast, IsAddressTakenScalarOrGlobalScalar)
ids = set()
for node, _ in candidates:
if isinstance(node, c_ast.UnaryOp):
ids.add(meta_info.sym_links[node.expr])
else:
ids.add(node)
one = c_ast.Constant("int", "1")
meta_info.type_links[one] = meta.INT_IDENTIFIER_TYPE
for node in ids:
assert isinstance(node, c_ast.Decl)
node.type = c_ast.ArrayDecl(node.type, one, [])
if node.init:
node.init = c_ast.InitList([node.init])
def IsAddressTakenScalarId(node, _):
return isinstance(node, c_ast.ID) and meta_info.sym_links[node] in ids
candidates = common.FindMatchingNodesPreOrder(ast, ast, IsAddressTakenScalarId)
for node, parent in candidates:
original_type = meta_info.type_links[node]
meta_info.type_links[node] = meta.GetTypeForDecl(meta_info.sym_links[node].type)
array_ref = c_ast.UnaryOp("*", node)
meta_info.type_links[array_ref] = original_type
common.ReplaceNode(parent, node, array_ref)
def ConvertCompoundAssignment(ast: c_ast.Node, meta_info: meta.MetaInfo, _id_gen):
"""This works best after ConvertArrayIndexToPointerDereference"""
candidates = common.FindMatchingNodesPostOrder(ast, ast, lambda n, _: isinstance(n, c_ast.Assignment))
for assign, parent in candidates:
if assign.op == "=":
continue
lvalue = assign.lvalue
if isinstance(lvalue, c_ast.ID):
node = c_ast.BinaryOp(assign.op[:-1], lvalue, assign.rvalue)
meta_info.type_links[node] = meta_info.type_links[assign]
assign.rvalue = node
assign.op = "="
elif isinstance(lvalue, c_ast.UnaryOp) and lvalue.op == "*":
# TODO
pass
def CanonicalizeFun(ast: c_ast.FuncDef, meta_info: meta.MetaInfo):
id_gen = common.UniqueId()
ConvertPostToPreIncDec(ast)
meta_info.CheckConsistency(ast)
ConvertPreIncDecToCompoundAssignment(ast, meta_info)
meta_info.CheckConsistency(ast)
ConvertWhileLoop(ast, id_gen)
ConvertForLoop(ast, id_gen)
meta_info.CheckConsistency(ast)
EliminateExpressionLists(ast)
transform_if.IfTransform(ast, id_gen)
transform_if.ShortCircuitIfTransform(ast, id_gen)
meta_info.CheckConsistency(ast)
transform_label.PruneUselessLabels(ast)
transform_rename.UniquifyLocalVars(ast, meta_info, id_gen)
FixNodeRequiringBoolInt(ast, meta_info)
meta_info.CheckConsistency(ast)
# if return type is void
decl: c_ast.FuncDecl = ast.decl
type_decl: c_ast.TypeDecl = decl.type.type
if not isinstance(type_decl.type, c_ast.IdentifierType):
return
if "void" not in type_decl.type.names:
return
if ast.body.block_items is None:
ast.body.block_items = []
stmts = ast.body.block_items
if not stmts or not isinstance(stmts[-1], c_ast.Return):
ret = c_ast.Return(None)
meta_info.type_links[ret] = meta.GetTypeForDecl(ast.decl.type)
stmts.append(ret)