backend code generation when python programm cotains class #2815

Activity

1. kmr-srbh commented on Nov 10, 2024

   

   kmr-srbh

   on Nov 10, 2024

   Contributor

   More actions

   @ljq-0814 LPython translates the source code into an intermediary form called an Abstract Semantic Representation (ASR). This form contains all the information related to the code, including type semantics. It is done inside python_ast_to_asr.cpp. You can see the generated ASR using the --show-asr flag.

   The above code gets translated to:

   (TranslationUnit
       (SymbolTable
           1
           {
               __main__:
                   (Module
                       (SymbolTable
                           2
                           {
                               student:
                                   (Struct
                                       (SymbolTable
                                           3
                                           {
                                               __init__:
                                                   (Function
                                                       (SymbolTable
                                                           4
                                                           {
                                                               age:
                                                                   (Variable
                                                                       4
                                                                       age
                                                                       []
                                                                       In
                                                                       ()
                                                                       ()
                                                                       Default
                                                                       (Integer 4)
                                                                       ()
                                                                       Source
                                                                       Public
                                                                       Required
                                                                       .false.
                                                                   ),
                                                               name:
                                                                   (Variable
                                                                       4
                                                                       name
                                                                       []
                                                                       In
                                                                       ()
                                                                       ()
                                                                       Default
                                                                       (Character 1 -2 ())
                                                                       ()
                                                                       Source
                                                                       Public
                                                                       Required
                                                                       .false.
                                                                   ),
                                                               self:
                                                                   (Variable
                                                                       4
                                                                       self
                                                                       []
                                                                       InOut
                                                                       ()
                                                                       ()
                                                                       Default
                                                                       (StructType
                                                                           [(Character 1 -2 ())
                                                                           (Integer 4)]
                                                                           [(FunctionType
                                                                               [(Class
                                                                                   2 student
                                                                               )
                                                                               (Character 1 -2 ())
                                                                               (Integer 4)]
                                                                               ()
                                                                               Source
                                                                               Implementation
                                                                               ()
                                                                               .false.
                                                                               .false.
                                                                               .false.
                                                                               .false.
                                                                               .false.
                                                                               []
                                                                               .false.
                                                                           )]
                                                                           .false.
                                                                           2 student
                                                                       )
                                                                       ()
                                                                       Source
                                                                       Public
                                                                       Required
                                                                       .false.
                                                                   )
                                                           })
                                                       __init__
                                                       (FunctionType
                                                           [(Class
                                                               2 student
                                                           )
                                                           (Character 1 -2 ())
                                                           (Integer 4)]
                                                           ()
                                                           Source
                                                           Implementation
                                                           ()
                                                           .false.
                                                           .false.
                                                           .false.
                                                           .false.
                                                           .false.
                                                           []
                                                           .false.
                                                       )
                                                       []
                                                       [(Var 4 self)
                                                       (Var 4 name)
                                                       (Var 4 age)]
                                                       [(Assignment
                                                           (StructInstanceMember
                                                               (Var 4 self)
                                                               3 name
                                                               (Character 1 -2 ())
                                                               ()
                                                           )
                                                           (Var 4 name)
                                                           ()
                                                       )
                                                       (Assignment
                                                           (StructInstanceMember
                                                               (Var 4 self)
                                                               3 age
                                                               (Integer 4)
                                                               ()
                                                           )
                                                           (Var 4 age)
                                                           ()
                                                       )]
                                                       ()
                                                       Public
                                                       .false.
                                                       .false.
                                                       ()
                                                   ),
                                               age:
                                                   (Variable
                                                       3
                                                       age
                                                       []
                                                       Local
                                                       ()
                                                       ()
                                                       Default
                                                       (Integer 4)
                                                       ()
                                                       Source
                                                       Public
                                                       Required
                                                       .false.
                                                   ),
                                               name:
                                                   (Variable
                                                       3
                                                       name
                                                       []
                                                       Local
                                                       ()
                                                       ()
                                                       Default
                                                       (Character 1 -2 ())
                                                       ()
                                                       Source
                                                       Public
                                                       Required
                                                       .false.
                                                   )
                                           })
                                       student
                                       []
                                       [name
                                       age]
                                       [__init__]
                                       Source
                                       Public
                                       .false.
                                       .false.
                                       [(())
                                       (())]
                                       ()
                                       ()
                                   )
                           })
                       __main__
                       []
                       .false.
                       .false.
                   ),
               main_program:
                   (Program
                       (SymbolTable
                           5
                           {
                               
                           })
                       main_program
                       []
                       []
                   )
           })
       []
   )

   We then apply some optimization passes to this initial ASR. The final ASR is passed over to the backend for further translation. The backend translator asr_to_*.cpp visits the ASR nodes and handles it appropriately. In C, the closest resemblance to a class is struct. We handle this case similarly. You can see the final transformed code after the backend visitor using the appropriate --show-* option (see --help). Currently, our implementation of OOP is basic. The above code gets translated to the following in the C backend:

   #include <inttypes.h>
   
   #include <stdlib.h>
   #include <stdbool.h>
   #include <stdio.h>
   #include <string.h>
   #include <lfortran_intrinsics.h>
   
   
   struct dimension_descriptor
   {
       int32_t lower_bound, length, stride;
   };
   struct student {
    char * name;
    int32_t age;
   };
   
   
   
   
   // Implementations
   int main(int argc, char* argv[])
   {
       _lpython_set_argv(argc, argv);
       return 0;
   }

   👍React with 👍1Reacted by ljq-0814