fix missing returns in the entry point function

Problem: we replace returns with empty strings in the main
     function. The reason is that we change the signature of the main
     function, add return variables, so the returns are not
     valid. However, it might change semantics and it leads to
     non-compiling code for the new contract 'ctor-check.sol'.

     Another issue is that sometimes we don't finalize certain
    implicits on early returns

Solution: transpile the main and constructor function as is, without
     any changes. Add wrappers that initialize and finalize implicits
     and perform the outermost returning. The semantics are unchanged
     and finalization is guaranteed.

Also now we add only necessary implicits to the constructor and main
     functions.

tests/ast/functions-to-prune.ast

@@ -6,7 +6,7 @@ Block:
 		Body:
 			Block:
 	FunctionDefinition:
-		Name: fun_ENTRY_POINT
+		Name: __main_meat
 		Parameters:
 		Return Variables:
 		Body:

tests/ast/functions-to-prune.ast.result

@@ -1,4 +1,4 @@
 {
 	function funD() {  }
-	function fun_ENTRY_POINT() { funD() }
+	function __main_meat() { funD() }
 }

tests/yul/ERC20.cairo

@@ -7,7 +7,6 @@ from evm.hashing import uint256_pedersen
 from evm.memory import uint256_mload, uint256_mstore
 from evm.uint256 import is_eq, is_gt, is_lt, is_zero, slt, u256_add, u256_shl, u256_shr
 from evm.yul_api import warp_return
-from starkware.cairo.common.alloc import alloc
 from starkware.cairo.common.cairo_builtins import BitwiseBuiltin, HashBuiltin
 from starkware.cairo.common.default_dict import default_dict_finalize, default_dict_new
 from starkware.cairo.common.dict_access import DictAccess
@@ -38,6 +37,39 @@ end
 func evm_storage(arg0_low, arg0_high) -> (res : Uint256):
 end
 
+@constructor
+func constructor{pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*}(
+        calldata_size, calldata_len, calldata : felt*):
+    alloc_locals
+    let (memory_dict) = default_dict_new(0)
+    let memory_dict_start = memory_dict
+    let msize = 0
+    with memory_dict, msize:
+        __constructor_meat()
+    end
+    default_dict_finalize(memory_dict_start, memory_dict, 0)
+    return ()
+end
+
+@external
+func __main{pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*}(
+        calldata_size, calldata_len, calldata : felt*) -> (
+        returndata_size, returndata_len, returndata : felt*):
+    alloc_locals
+    let (__fp__, _) = get_fp_and_pc()
+    local exec_env_ : ExecutionEnvironment = ExecutionEnvironment(calldata_size=calldata_size, calldata_len=calldata_len, calldata=calldata, returndata_size=0, returndata_len=0, returndata=cast(0, felt*), to_returndata_size=0, to_returndata_len=0, to_returndata=cast(0, felt*))
+    let exec_env : ExecutionEnvironment* = &exec_env_
+    let (memory_dict) = default_dict_new(0)
+    let memory_dict_start = memory_dict
+    let msize = 0
+    let termination_token = 0
+    with exec_env, memory_dict, msize, termination_token:
+        __main_meat()
+    end
+    default_dict_finalize(memory_dict_start, memory_dict, 0)
+    return (exec_env.to_returndata_size, exec_env.to_returndata_len, exec_env.to_returndata)
+end
+
 func update_byte_slice_shift_deployment(value : Uint256, toInsert : Uint256) -> (result : Uint256):
     alloc_locals
     let result : Uint256 = toInsert
@@ -61,29 +93,18 @@ func constructor_WARP{pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr
     return ()
 end
 
-@constructor
-func constructor{
-        pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*,
-        bitwise_ptr : BitwiseBuiltin*}(calldata_size, calldata_len, calldata : felt*):
+func __constructor_meat{
+        memory_dict : DictAccess*, msize, pedersen_ptr : HashBuiltin*, range_check_ptr,
+        syscall_ptr : felt*}() -> ():
     alloc_locals
-    let termination_token = 0
-    let (returndata_ptr : felt*) = alloc()
-    let (__fp__, _) = get_fp_and_pc()
-    local exec_env_ : ExecutionEnvironment = ExecutionEnvironment(calldata_size=calldata_size, calldata_len=calldata_len, calldata=calldata, returndata_size=0, returndata_len=0, returndata=returndata_ptr, to_returndata_size=0, to_returndata_len=0, to_returndata=returndata_ptr)
-    let exec_env : ExecutionEnvironment* = &exec_env_
-    let (memory_dict) = default_dict_new(0)
-    let memory_dict_start = memory_dict
-    let msize = 0
-    with memory_dict, msize, exec_env, termination_token:
-        uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
-        let (__warp_subexpr_0 : Uint256) = __warp_constant_0()
-        if __warp_subexpr_0.low + __warp_subexpr_0.high != 0:
-            assert 0 = 1
-            jmp rel 0
-        end
-        constructor_WARP()
-        return ()
+    uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
+    let (__warp_subexpr_0 : Uint256) = __warp_constant_0()
+    if __warp_subexpr_0.low + __warp_subexpr_0.high != 0:
+        assert 0 = 1
+        jmp rel 0
     end
+    constructor_WARP()
+    return ()
 end
 
 func abi_decode{range_check_ptr}(headStart : Uint256, dataEnd : Uint256) -> ():
@@ -690,31 +711,19 @@ func __warp_if_0{
     end
 end
 
-@external
-func fun_ENTRY_POINT{
-        pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*,
-        bitwise_ptr : BitwiseBuiltin*}(calldata_size, calldata_len, calldata : felt*) -> (
-        returndata_size : felt, returndata_len : felt, returndata : felt*):
+func __main_meat{
+        exec_env : ExecutionEnvironment*, memory_dict : DictAccess*, msize,
+        pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*, termination_token}() -> (
+        ):
     alloc_locals
-    let termination_token = 0
-    let (__fp__, _) = get_fp_and_pc()
-    let (returndata_ptr : felt*) = alloc()
-    local exec_env_ : ExecutionEnvironment = ExecutionEnvironment(calldata_size=calldata_size, calldata_len=calldata_len, calldata=calldata, returndata_size=0, returndata_len=0, returndata=returndata_ptr, to_returndata_size=0, to_returndata_len=0, to_returndata=returndata_ptr)
-    let exec_env = &exec_env_
-    let (memory_dict) = default_dict_new(0)
-    let memory_dict_start = memory_dict
-    let msize = 0
-    with exec_env, msize, memory_dict, termination_token:
-        uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
-        let (__warp_subexpr_2 : Uint256) = calldatasize()
-        let (__warp_subexpr_1 : Uint256) = is_lt(__warp_subexpr_2, Uint256(low=4, high=0))
-        let (__warp_subexpr_0 : Uint256) = is_zero(__warp_subexpr_1)
-        __warp_if_0(__warp_subexpr_0)
-        if termination_token == 1:
-            default_dict_finalize(memory_dict_start, memory_dict, 0)
-            return (exec_env.to_returndata_size, exec_env.to_returndata_len, exec_env.to_returndata)
-        end
-        assert 0 = 1
-        jmp rel 0
+    uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
+    let (__warp_subexpr_2 : Uint256) = calldatasize()
+    let (__warp_subexpr_1 : Uint256) = is_lt(__warp_subexpr_2, Uint256(low=4, high=0))
+    let (__warp_subexpr_0 : Uint256) = is_zero(__warp_subexpr_1)
+    __warp_if_0(__warp_subexpr_0)
+    if termination_token == 1:
+        return ()
     end
+    assert 0 = 1
+    jmp rel 0
 end

tests/yul/ERC20_storage.cairo

@@ -7,7 +7,6 @@ from evm.hashing import uint256_pedersen
 from evm.memory import uint256_mload, uint256_mstore
 from evm.uint256 import is_eq, is_gt, is_lt, is_zero, slt, u256_add, u256_shl, u256_shr
 from evm.yul_api import warp_return
-from starkware.cairo.common.alloc import alloc
 from starkware.cairo.common.cairo_builtins import BitwiseBuiltin, HashBuiltin
 from starkware.cairo.common.default_dict import default_dict_finalize, default_dict_new
 from starkware.cairo.common.dict_access import DictAccess
@@ -38,6 +37,39 @@ end
 func evm_storage(arg0_low, arg0_high) -> (res : Uint256):
 end
 
+@constructor
+func constructor{pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*}(
+        calldata_size, calldata_len, calldata : felt*):
+    alloc_locals
+    let (memory_dict) = default_dict_new(0)
+    let memory_dict_start = memory_dict
+    let msize = 0
+    with memory_dict, msize:
+        __constructor_meat()
+    end
+    default_dict_finalize(memory_dict_start, memory_dict, 0)
+    return ()
+end
+
+@external
+func __main{pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*}(
+        calldata_size, calldata_len, calldata : felt*) -> (
+        returndata_size, returndata_len, returndata : felt*):
+    alloc_locals
+    let (__fp__, _) = get_fp_and_pc()
+    local exec_env_ : ExecutionEnvironment = ExecutionEnvironment(calldata_size=calldata_size, calldata_len=calldata_len, calldata=calldata, returndata_size=0, returndata_len=0, returndata=cast(0, felt*), to_returndata_size=0, to_returndata_len=0, to_returndata=cast(0, felt*))
+    let exec_env : ExecutionEnvironment* = &exec_env_
+    let (memory_dict) = default_dict_new(0)
+    let memory_dict_start = memory_dict
+    let msize = 0
+    let termination_token = 0
+    with exec_env, memory_dict, msize, termination_token:
+        __main_meat()
+    end
+    default_dict_finalize(memory_dict_start, memory_dict, 0)
+    return (exec_env.to_returndata_size, exec_env.to_returndata_len, exec_env.to_returndata)
+end
+
 func update_byte_slice_shift_0{range_check_ptr}(value : Uint256, toInsert : Uint256) -> (
         result : Uint256):
     alloc_locals
@@ -85,29 +117,18 @@ func constructor_WARP{pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr
     return ()
 end
 
-@constructor
-func constructor{
-        pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*,
-        bitwise_ptr : BitwiseBuiltin*}(calldata_size, calldata_len, calldata : felt*):
+func __constructor_meat{
+        memory_dict : DictAccess*, msize, pedersen_ptr : HashBuiltin*, range_check_ptr,
+        syscall_ptr : felt*}() -> ():
     alloc_locals
-    let termination_token = 0
-    let (returndata_ptr : felt*) = alloc()
-    let (__fp__, _) = get_fp_and_pc()
-    local exec_env_ : ExecutionEnvironment = ExecutionEnvironment(calldata_size=calldata_size, calldata_len=calldata_len, calldata=calldata, returndata_size=0, returndata_len=0, returndata=returndata_ptr, to_returndata_size=0, to_returndata_len=0, to_returndata=returndata_ptr)
-    let exec_env : ExecutionEnvironment* = &exec_env_
-    let (memory_dict) = default_dict_new(0)
-    let memory_dict_start = memory_dict
-    let msize = 0
-    with memory_dict, msize, exec_env, termination_token:
-        uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
-        let (__warp_subexpr_0 : Uint256) = __warp_constant_0()
-        if __warp_subexpr_0.low + __warp_subexpr_0.high != 0:
-            assert 0 = 1
-            jmp rel 0
-        end
-        constructor_WARP()
-        return ()
+    uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
+    let (__warp_subexpr_0 : Uint256) = __warp_constant_0()
+    if __warp_subexpr_0.low + __warp_subexpr_0.high != 0:
+        assert 0 = 1
+        jmp rel 0
     end
+    constructor_WARP()
+    return ()
 end
 
 func abi_decode{range_check_ptr}(headStart : Uint256, dataEnd : Uint256) -> ():
@@ -731,31 +752,19 @@ func __warp_if_1{
     end
 end
 
-@external
-func fun_ENTRY_POINT{
-        pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*,
-        bitwise_ptr : BitwiseBuiltin*}(calldata_size, calldata_len, calldata : felt*) -> (
-        returndata_size : felt, returndata_len : felt, returndata : felt*):
+func __main_meat{
+        exec_env : ExecutionEnvironment*, memory_dict : DictAccess*, msize,
+        pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*, termination_token}() -> (
+        ):
     alloc_locals
-    let termination_token = 0
-    let (__fp__, _) = get_fp_and_pc()
-    let (returndata_ptr : felt*) = alloc()
-    local exec_env_ : ExecutionEnvironment = ExecutionEnvironment(calldata_size=calldata_size, calldata_len=calldata_len, calldata=calldata, returndata_size=0, returndata_len=0, returndata=returndata_ptr, to_returndata_size=0, to_returndata_len=0, to_returndata=returndata_ptr)
-    let exec_env = &exec_env_
-    let (memory_dict) = default_dict_new(0)
-    let memory_dict_start = memory_dict
-    let msize = 0
-    with exec_env, msize, memory_dict, termination_token:
-        uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
-        let (__warp_subexpr_2 : Uint256) = calldatasize()
-        let (__warp_subexpr_1 : Uint256) = is_lt(__warp_subexpr_2, Uint256(low=4, high=0))
-        let (__warp_subexpr_0 : Uint256) = is_zero(__warp_subexpr_1)
-        __warp_if_1(__warp_subexpr_0)
-        if termination_token == 1:
-            default_dict_finalize(memory_dict_start, memory_dict, 0)
-            return (exec_env.to_returndata_size, exec_env.to_returndata_len, exec_env.to_returndata)
-        end
-        assert 0 = 1
-        jmp rel 0
+    uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
+    let (__warp_subexpr_2 : Uint256) = calldatasize()
+    let (__warp_subexpr_1 : Uint256) = is_lt(__warp_subexpr_2, Uint256(low=4, high=0))
+    let (__warp_subexpr_0 : Uint256) = is_zero(__warp_subexpr_1)
+    __warp_if_1(__warp_subexpr_0)
+    if termination_token == 1:
+        return ()
     end
+    assert 0 = 1
+    jmp rel 0
 end

tests/yul/address.cairo

@@ -6,7 +6,6 @@ from evm.exec_env import ExecutionEnvironment
 from evm.memory import uint256_mstore
 from evm.uint256 import is_eq, is_lt, is_zero, slt, u256_add, u256_shr
 from evm.yul_api import address, warp_return
-from starkware.cairo.common.alloc import alloc
 from starkware.cairo.common.cairo_builtins import BitwiseBuiltin, HashBuiltin
 from starkware.cairo.common.default_dict import default_dict_finalize, default_dict_new
 from starkware.cairo.common.dict_access import DictAccess
@@ -18,27 +17,46 @@ func __warp_constant_0() -> (res : Uint256):
 end
 
 @constructor
-func constructor{
-        pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*,
-        bitwise_ptr : BitwiseBuiltin*}(calldata_size, calldata_len, calldata : felt*):
+func constructor{range_check_ptr}(calldata_size, calldata_len, calldata : felt*):
+    alloc_locals
+    let (memory_dict) = default_dict_new(0)
+    let memory_dict_start = memory_dict
+    let msize = 0
+    with memory_dict, msize:
+        __constructor_meat()
+    end
+    default_dict_finalize(memory_dict_start, memory_dict, 0)
+    return ()
+end
+
+@external
+func __main{range_check_ptr, syscall_ptr : felt*}(
+        calldata_size, calldata_len, calldata : felt*) -> (
+        returndata_size, returndata_len, returndata : felt*):
     alloc_locals
-    let termination_token = 0
-    let (returndata_ptr : felt*) = alloc()
     let (__fp__, _) = get_fp_and_pc()
-    local exec_env_ : ExecutionEnvironment = ExecutionEnvironment(calldata_size=calldata_size, calldata_len=calldata_len, calldata=calldata, returndata_size=0, returndata_len=0, returndata=returndata_ptr, to_returndata_size=0, to_returndata_len=0, to_returndata=returndata_ptr)
+    local exec_env_ : ExecutionEnvironment = ExecutionEnvironment(calldata_size=calldata_size, calldata_len=calldata_len, calldata=calldata, returndata_size=0, returndata_len=0, returndata=cast(0, felt*), to_returndata_size=0, to_returndata_len=0, to_returndata=cast(0, felt*))
     let exec_env : ExecutionEnvironment* = &exec_env_
     let (memory_dict) = default_dict_new(0)
     let memory_dict_start = memory_dict
     let msize = 0
-    with memory_dict, msize, exec_env, termination_token:
-        uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
-        let (__warp_subexpr_0 : Uint256) = __warp_constant_0()
-        if __warp_subexpr_0.low + __warp_subexpr_0.high != 0:
-            assert 0 = 1
-            jmp rel 0
-        else:
-            return ()
-        end
+    let termination_token = 0
+    with exec_env, memory_dict, msize, termination_token:
+        __main_meat()
+    end
+    default_dict_finalize(memory_dict_start, memory_dict, 0)
+    return (exec_env.to_returndata_size, exec_env.to_returndata_len, exec_env.to_returndata)
+end
+
+func __constructor_meat{memory_dict : DictAccess*, msize, range_check_ptr}() -> ():
+    alloc_locals
+    uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
+    let (__warp_subexpr_0 : Uint256) = __warp_constant_0()
+    if __warp_subexpr_0.low + __warp_subexpr_0.high != 0:
+        assert 0 = 1
+        jmp rel 0
+    else:
+        return ()
     end
 end
 
@@ -120,31 +138,18 @@ func __warp_if_0{
     end
 end
 
-@external
-func fun_ENTRY_POINT{
-        pedersen_ptr : HashBuiltin*, range_check_ptr, syscall_ptr : felt*,
-        bitwise_ptr : BitwiseBuiltin*}(calldata_size, calldata_len, calldata : felt*) -> (
-        returndata_size : felt, returndata_len : felt, returndata : felt*):
+func __main_meat{
+        exec_env : ExecutionEnvironment*, memory_dict : DictAccess*, msize, range_check_ptr,
+        syscall_ptr : felt*, termination_token}() -> ():
     alloc_locals
-    let termination_token = 0
-    let (__fp__, _) = get_fp_and_pc()
-    let (returndata_ptr : felt*) = alloc()
-    local exec_env_ : ExecutionEnvironment = ExecutionEnvironment(calldata_size=calldata_size, calldata_len=calldata_len, calldata=calldata, returndata_size=0, returndata_len=0, returndata=returndata_ptr, to_returndata_size=0, to_returndata_len=0, to_returndata=returndata_ptr)
-    let exec_env = &exec_env_
-    let (memory_dict) = default_dict_new(0)
-    let memory_dict_start = memory_dict
-    let msize = 0
-    with exec_env, msize, memory_dict, termination_token:
-        uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
-        let (__warp_subexpr_2 : Uint256) = calldatasize()
-        let (__warp_subexpr_1 : Uint256) = is_lt(__warp_subexpr_2, Uint256(low=4, high=0))
-        let (__warp_subexpr_0 : Uint256) = is_zero(__warp_subexpr_1)
-        __warp_if_0(__warp_subexpr_0)
-        if termination_token == 1:
-            default_dict_finalize(memory_dict_start, memory_dict, 0)
-            return (exec_env.to_returndata_size, exec_env.to_returndata_len, exec_env.to_returndata)
-        end
-        assert 0 = 1
-        jmp rel 0
+    uint256_mstore(offset=Uint256(low=64, high=0), value=Uint256(low=128, high=0))
+    let (__warp_subexpr_2 : Uint256) = calldatasize()
+    let (__warp_subexpr_1 : Uint256) = is_lt(__warp_subexpr_2, Uint256(low=4, high=0))
+    let (__warp_subexpr_0 : Uint256) = is_zero(__warp_subexpr_1)
+    __warp_if_0(__warp_subexpr_0)
+    if termination_token == 1:
+        return ()
     end
+    assert 0 = 1
+    jmp rel 0
 end