Minimal AOT compiled example

For ahead-of-time (AOT) compiled programs, there are two source files involved. The first, "halide_generate.cpp", defines and builds a Halide pipeline, then compiles it into an object file. The second, "halide_run.cpp", will use this object file to run the pipeline.

halide_generate.cpp:

#include <Halide.h>
#include <stdio.h>

int main(int argc, char **argv) {
  // Define a gradient function.
  Halide::Func f;
  Halide::Var x, y;
  f(x, y) = x + y;
 
  std::vector<Halide::Argument> args(0);
  // Compile it to an object file and header.
  f.compile_to_file("gradient", args);

  return 0;
}

Compile and run it. On linux, that looks like:

% g++ halide_generate.cpp -I Halide/include -L Halide/lib -lHalide -o halide_generate -std=c++11
% LD_LIBRARY_PATH=Halide/lib ./halide_generate
% ls gradient.*
gradient.h gradient.o

(where Halide/include is the folder containing Halide.h, and Halide/lib is the folder containing libHalide.so.)

halide_run.cpp:

// Compiling and running halide_generate.cpp produced the following header:
#include "gradient.h"

// Note we don't include Halide.h. This program doesn't depend on libHalide. We will however include a Buffer helper type:
#include "HalideBuffer.h"

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv) {
    // This pipeline has no inputs. We still need to make a buffer
    // to hold the output.
    Halide::Runtime::Buffer<int> output(32, 32);

    // Run the pipeline
    f(output);

    // Print the result.
    for (int y = 0; y < 32; y++) {
        for (int x = 0; x < 32; x++) {
            printf("%3d ", output(x, y));
        }
        printf("\n");
    }

    return 0;
}

Compile and run it:

% g++ halide_run.cpp gradient.o -lpthread -o halide_run
% ./halide_run
  0   1   2   3 ....

For a more complete example of AOT compilation, see tutorial lesson 10. For more complex examples, browse the static tests, and the apps in the repository.