# Compilation contexts

class `gccjit.``Context`

  The top-level of the API is the gccjit.Context class.

  A gccjit.Context instance encapsulates the state of a compilation.

  You can set up options on it, and add types, functions and code. Invoking `gccjit.Context.compile()` on it gives you a `gccjit.Result`.

  > `dump_to_file`(path, update_locations)
  > `get_first_error`()
  > `new_location`(filename, line, column)

  >   Make a `gccjit.Location` representing a source location, for use by the debugger:

  >       loc = ctxt.new_location('web.js', 5, 0)

  >   Note

  >   You need to enable `gccjit.BoolOption.DEBUGINFO` on the context for these locations to actually be usable by the debugger:

  >       ctxt.set_bool_option(gccjit.BoolOption.DEBUGINFO, True)

  >   Return type: | `gccjit.Location`

  > `new_global`(Type type_, name, Location loc=None)

  >   Return type: | `gccjit.LValue`

  > `new_array_type`(Type element_type, int num_elements, Location loc=None)

  >   Return type: | `gccjit.Type`

  > `new_field`(Type type_, name, Location loc=None)

  >   Return type: | `gccjit.Field`

  > `new_struct`(name, fields=None, Location loc=None)

  >   Return type: | `gccjit.Struct`

  > `new_union`(name, fields=None, Location loc=None)

  >   Construct a new “union” type.

  >   Return type: | `gccjit.Type`

  >   Parameters:

  >   - field – The fields that make up the union
  >   - loc (`gccjit.Location`) – The source location, if any, or None

  >   For example, to create the equivalent of:

  >       union u
  >       {
  >         int as_int;
  >         float as_float;
  >       };

  >   you can use:

  >       ctxt = gccjit.Context()
  >       int_type = ctxt.get_type(gccjit.TypeKind.INT)
  >       float_type = ctxt.get_type(gccjit.TypeKind.FLOAT)
  >       as_int = ctxt.new_field(int_type, b'as_int')
  >       as_float = ctxt.new_field(float_type, b'as_float')
  >       u = ctxt.new_union(b'u', [as_int, as_float])

  > `new_function_ptr_type`(return_type, param_types, loc=None, is_variadic=False)

  >   Parameters:

  >   - return_type (`gccjit.Type`) – The return type of the function
  >   - param_types (A sequence of `gccjit.Type`) – The types of the parameters
  >   - loc (`gccjit.Location`) – The source location, if any, or None
  >   - is_variadic (`bool`) – Is the function variadic (i.e. accepts a variable number of arguments)

  >   Return type: | `gccjit.Type`

  >   For example, to create the equivalent of:

  >       typedef void (*fn_ptr_type) (int, int int);

  >   you can use:

  >       >>> ctxt = gccjit.Context()
  >       >>> void_type = ctxt.get_type(gccjit.TypeKind.VOID)
  >       >>> int_type = ctxt.get_type(gccjit.TypeKind.INT)
  >       >>> fn_ptr_type = ctxt.new_function_ptr_type (void_type,
  >                                                     [int_type,
  >                                                      int_type,
  >                                                      int_type])
  >       >>> print(fn_ptr_type)
  >       void (*) (int, int, int)

  > `new_param`(Type type_, name, Location loc=None)

  >   Return type: | `gccjit.Param`

  > `new_function`(kind, Type return_type, name, params, Location loc=None, is_variadic=False)

  >   Return type: | `gccjit.Function`

  > `get_builtin_function`(name)

  >   Return type: | `gccjit.Function`

  > `zero`(type_)

  >   Given a `gccjit.Type`, which must be a numeric type, get the constant 0 as a `gccjit.RValue` of that type.

  >   Return type: | `gccjit.RValue`

  > `one`(type_)

  >   Given a `gccjit.Type`, which must be a numeric type, get the constant 1 as a `gccjit.RValue` of that type.

  >   Return type: | `gccjit.RValue`

  > `new_rvalue_from_double`(numeric_type, value)

  >   Given a `gccjit.Type`, which must be a numeric type, get a floating-point constant as a `gccjit.RValue` of that type.

  >   Return type: | `gccjit.RValue`

  > `new_rvalue_from_int`(type_, value)

  >   Given a `gccjit.Type`, which must be a numeric type, get an integer constant as a `gccjit.RValue` of that type.

  >   Return type: | `gccjit.RValue`

  > `new_rvalue_from_ptr`(pointer_type, value)

  >   Given a `gccjit.Type`, which must be a pointer type, and an address, get a `gccjit.RValue` representing that address as a pointer of that type:

  >       ptr = ctxt.new_rvalue_from_ptr(int_star, 0xDEADBEEF)

  >   Return type: | `gccjit.RValue`

  > `null`(pointer_type)

  >   Given a `gccjit.Type`, which must be a pointer type, get a `gccjit.RValue` representing the NULL pointer of that type:

  >       ptr = ctxt.null(int_star)

  >   Return type: | `gccjit.RValue`

  > `new_string_literal`(value)

  >   Make a `gccjit.RValue` for the given string literal value (actually bytes):

  >       msg = ctxt.new_string_literal(b'hello world\n')

  >   Parameters: | value (bytes) – the bytes of the string literal
  >   Return type: | `gccjit.RValue`

  > `new_unary_op`(op, result_type, rvalue, loc=None)

  >   Make a `gccjit.RValue` for the given unary operation.

  >   Parameters:

  >   - op (`gccjit.UnaryOp`) – Which unary operation
  >   - result_type (`gccjit.Type`) – The type of the result
  >   - rvalue (`gccjit.RValue`) – The input expression
  >   - loc (`gccjit.Location`) – The source location, if any, or None

  >   Return type: | `gccjit.RValue`

  > `new_binary_op`(op, result_type, a, b, loc=None)

  >   Make a `gccjit.RValue` for the given binary operation.

  >   Parameters:

  >   - op (`gccjit.BinaryOp`) – Which binary operation
  >   - result_type (`gccjit.Type`) – The type of the result
  >   - a (`gccjit.RValue`) – The first input expression
  >   - b (`gccjit.RValue`) – The second input expression
  >   - loc (`gccjit.Location`) – The source location, if any, or None

  >   Return type: | `gccjit.RValue`

  > `new_comparison`(op, a, b, loc=None)

  >   Make a `gccjit.RValue` of boolean type for the given comparison.

  >   Parameters:

  >   - op (`gccjit.Comparison`) – Which comparison
  >   - a (`gccjit.RValue`) – The first input expression
  >   - b (`gccjit.RValue`) – The second input expression
  >   - loc (`gccjit.Location`) – The source location, if any, or None

  >   Return type: | `gccjit.RValue`

  > `new_child_context`(self)

  >   Return type: | `gccjit.Context`

  > `new_cast`(RValue rvalue, Type type_, Location loc=None)

  >   Return type: | `gccjit.RValue`

  > `new_array_access`(ptr, index, loc=None)

  >   Parameters:

  >   - ptr (`gccjit.RValue`) – The pointer or array
  >   - index (`gccjit.RValue`) – The index within the array
  >   - loc (`gccjit.Location`) – The source location, if any, or None

  >   Return type: | `gccjit.LValue`

  > `new_call`(Function func, args, Location loc=None)

  >   Return type: | `gccjit.RValue`

  > `new_call_through_ptr`(fn_ptr, args, loc=None)

  >   Parameters:

  >   - fn_ptr (`gccjit.RValue`) – A function pointer
  >   - args (A sequence of `gccjit.RValue`) – The arguments to the function call
  >   - loc (`gccjit.Location`) – The source location, if any, or None

  >   Return type: | `gccjit.RValue`

  >   For example, to create the equivalent of:

  >       typedef void (*fn_ptr_type) (int, int, int);
  >       fn_ptr_type fn_ptr;

  >       fn_ptr (a, b, c);

  >   you can use:

  >       block.add_eval (ctxt.new_call_through_ptr(fn_ptr, [a, b, c]))

## Debugging

`gccjit.Context.``dump_reproducer_to_file`(self, path)

  Write C source code into path that can be compiled into a self-contained executable (i.e. with libgccjit as the only dependency). The generated code will attempt to replay the API calls that have been made into the given context, at the C level, eliminating any dependency on Python or on client code or data.

  This may be useful when debugging the library or client code, for reducing a complicated recipe for reproducing a bug into a simpler form.

  Typically you need to supply `-Wno-unused-variable` when compiling the generated file (since the result of each API call is assigned to a unique variable within the generated C source, and not all are necessarily then used).

`gccjit.Context.``set_logfile`(self, f)

  To help with debugging; enable ongoing logging of the context’s activity to the given file object.

  For example, the following will enable logging to stderr:

      ctxt.set_logfile(sys.stderr)

  Examples of information logged include:

  > - API calls
  > - the various steps involved within compilation
  > - activity on any `gccjit.Result` instances created by the context
  > - activity within any child contexts

  The precise format and kinds of information logged is subject to change.

  Unfortunately, doing so creates a leak of an underlying `FILE *` object.

  There may a performance cost for logging.

## Options

### String options

`gccjit.Context.``set_str_option`(self, opt, val)

  Set a string option of the context; see `gccjit.StrOption` for notes on the options and their meanings.

  Parameters:

  - opt (`gccjit.StrOption`) – Which option to set
  - val (str) – The new value

class `gccjit.``StrOption`
  `PROGNAME`

    The name of the program, for use as a prefix when printing error messages to stderr. If None, or default, “libgccjit.so” is used.

### Boolean options

`gccjit.Context.``set_bool_option`(self, opt, val)

  Set a boolean option of the context; see `gccjit.BoolOption` for notes on the options and their meanings.

  Parameters:

  - opt (`gccjit.BoolOption`) – Which option to set
  - val (str) – The new value

class `gccjit.``BoolOption`
  `DEBUGINFO`

    If true, `gccjit.Context.compile()` will attempt to do the right thing so that if you attach a debugger to the process, it will be able to inspect variables and step through your code.

    Note that you can’t step through code unless you set up source location information for the code (by creating and passing in gccjit.Location instances).

  `DUMP_INITIAL_TREE`

    If true, `gccjit.Context.compile()` will dump its initial “tree” representation of your code to stderr (before any optimizations).

    Here’s some sample output (from the square example):

        <statement_list 0x7f4875a62cc0
           type <void_type 0x7f4875a64bd0 VOID
               align 8 symtab 0 alias set -1 canonical type 0x7f4875a64bd0
               pointer_to_this <pointer_type 0x7f4875a64c78>>
           side-effects head 0x7f4875a761e0 tail 0x7f4875a761f8 stmts 0x7f4875a62d20 0x7f4875a62d00

           stmt <label_expr 0x7f4875a62d20 type <void_type 0x7f4875a64bd0>
               side-effects
               arg 0 <label_decl 0x7f4875a79080 entry type <void_type 0x7f4875a64bd0>
                   VOID file (null) line 0 col 0
                   align 1 context <function_decl 0x7f4875a77500 square>>>
           stmt <return_expr 0x7f4875a62d00
               type <integer_type 0x7f4875a645e8 public SI
                   size <integer_cst 0x7f4875a623a0 constant 32>
                   unit size <integer_cst 0x7f4875a623c0 constant 4>
                   align 32 symtab 0 alias set -1 canonical type 0x7f4875a645e8 precision 32 min <integer_cst 0x7f4875a62340 -2147483648> max <integer_cst 0x7f4875a62360 2147483647>
                   pointer_to_this <pointer_type 0x7f4875a6b348>>
               side-effects
               arg 0 <modify_expr 0x7f4875a72a78 type <integer_type 0x7f4875a645e8>
                   side-effects arg 0 <result_decl 0x7f4875a7a000 D.54>
                   arg 1 <mult_expr 0x7f4875a72a50 type <integer_type 0x7f4875a645e8>
                       arg 0 <parm_decl 0x7f4875a79000 i> arg 1 <parm_decl 0x7f4875a79000 i>>>>>

  `DUMP_INITIAL_GIMPLE`

    If true, `gccjit.Context.compile()` will dump the “gimple” representation of your code to stderr, before any optimizations are performed. The dump resembles C code:

        square (signed int i)
        {
          signed int D.56;

          entry:
          D.56 = i * i;
          return D.56;
        }

  `DUMP_GENERATED_CODE`

    If true, `gccjit.Context.compile()` will dump the final generated code to stderr, in the form of assembly language:

            .file    "fake.c"
            .text
            .globl    square
            .type    square, @function
        square:
        .LFB0:
            .cfi_startproc
            pushq    %rbp
            .cfi_def_cfa_offset 16
            .cfi_offset 6, -16
            movq    %rsp, %rbp
            .cfi_def_cfa_register 6
            movl    %edi, -4(%rbp)
        .L2:
            movl    -4(%rbp), %eax
            imull    -4(%rbp), %eax
            popq    %rbp
            .cfi_def_cfa 7, 8
            ret
            .cfi_endproc
        .LFE0:
            .size    square, .-square
            .ident    "GCC: (GNU) 4.9.0 20131023 (Red Hat 0.1-%{gcc_release})"
            .section    .note.GNU-stack,"",@progbits

  `DUMP_SUMMARY`

    If true, `gccjit.Context.compile()` will print information to stderr on the actions it is performing, followed by a profile showing the time taken and memory usage of each phase.

  `DUMP_EVERYTHING`

    If true, `gccjit.Context.compile()` will dump copious amount of information on what it’s doing to various files within a temporary directory. Use `gccjit.BoolOption.KEEP_INTERMEDIATES` (see below) to see the results. The files are intended to be human-readable, but the exact files and their formats are subject to change.

  `SELFCHECK_GC`

    If true, libgccjit will aggressively run its garbage collector, to shake out bugs (greatly slowing down the compile). This is likely to only be of interest to developers of the library. It is used when running the selftest suite.

  `KEEP_INTERMEDIATES`

    If true, the gccjit.Context will not clean up intermediate files written to the filesystem, and will display their location on stderr.

### Integer options

`gccjit.Context.``set_int_option`(seld, opt, val)

  Set an integer option of the context; see `gccjit.IntOption` for notes on the options and their meanings.

  Parameters:

  - opt (`gccjit.IntOption`) – Which option to set
  - val (str) – The new value

class `gccjit.``IntOption`
  `OPTIMIZATION_LEVEL`

    How much to optimize the code.

    Valid values are 0-3, corresponding to GCC’s command-line options -O0 through -O3.

    The default value is 0 (unoptimized).