jitc

This project is NOT usable yet (check TODO)

An embeddable C JIT compiler.

Mission

Fill the hole where there's no lightweight, embeddable C JIT compiler that makes interop near plug and play.

TODO

• Parameters/returns in function prolog and epilog
• Varargs
• Correct codegen for ternary operator
• Short circuiting
• Switch statements
• Initializers
• Assembling to machine code
• Virtual headers (#include)
• Windows support

Calling it done here, the things below are planned but not guaranteed

• Implement macro support
• Implement goto
• aarch64 support
• Rewrite IR into SSA
• Implement custom extensions
  • GNU statement expressions
  • GNU ternary syntax (x ? : y)
  • switch expressions
  • Zig's defer or GNU __attribute__((cleanup)), either one of the two
  • C++ lambdas
  • C++ templates (won't blow up to the complexity of C++)
  • C++ operator overloading (also won't blow up to C++'s complexity)

Note to self: When implementing extension features, still make programs as explicit as possible (minimal implicit behavior cough cough C++ cough)

Differences from real C

• volatile, register, restrict and inline do nothing
• long double is the same as double
• No VLAs
• No bitfields
• No variable shadowing
• No wide strings or characters
• No macros, only #include (for now)
• No goto (for now)
• No alloca, auto, constexpr or signed
• sizeof and alignof must have parentheses
• No underscore-prefixed keywords:
  • _Alignof -> alignof
  • _Bool -> bool
  • Every other underscore-prefixed keyword is unsupported

API

• struct jitc_error_t

  • const char* msg - Error message
  • const char* file - Name of the file where the error occured
  • int row - Line number of the error location
  • int col - Column number of the error location
  • It is the caller's responsibility to free the object if it receives it from jitc_parse or jitc_parse_file

• jitc_context_t* jitc_create_context()

  • Creates a new context

• jitc_error_t* jitc_parse(jitc_context_t* context, const char* code, const char* filename)

  • Parses source code from memory, returns NULL if successful, an error object if not
  • filename: Can be NULL, specifies the filename for the lexer

• jitc_error_t* jitc_parse_file(jitc_context* context, const char* file)

  • Reads a file from the filesystem and parses its contents, returns NULL if successful, an error object if not

• void* jitc_get(jitc_context* context, const char* name)

  • Returns a symbol from the context, NULL if it doesn't exist

• void jitc_destroy_context(jitc_context_t* context)

  • Destroys a context and all the variables and functions declared with it

To use a symbol from the host, use extern. extern cannot be used to reference symbols from other contexts.