enzyme/test/Integration/ReverseMode/customalloc.c

// This should work on LLVM 7, 8, 9, however in CI the version of clang installed on Ubuntu 18.04 cannot load
// a clang plugin properly without segfaulting on exit. This is fine on Ubuntu 20.04 or later LLVM versions...
// New PM doesn't work on O0 until LLVM12
// RUN: if [ %llvmver -ge 10 ]; then %clang -std=c11 -O0 %s -S -emit-llvm -o - %loadClangEnzyme | %lli - ; fi
// RUN: if [ %llvmver -ge 10 ]; then %clang -std=c11 -O1 %s -S -emit-llvm -o - %loadClangEnzyme | %lli - ; fi
// RUN: if [ %llvmver -ge 10 ]; then %clang -std=c11 -O2 %s -S -emit-llvm -o - %loadClangEnzyme | %lli - ; fi
// RUN: if [ %llvmver -ge 10 ]; then %clang -std=c11 -O3 %s -S -emit-llvm -o - %loadClangEnzyme | %lli - ; fi
// RUN: if [ %llvmver -ge 10 ]; then %clang -std=c11 -O0 %s -S -emit-llvm -o - %loadClangEnzyme -mllvm -enzyme-inline=1 -S | %lli - ; fi
// RUN: if [ %llvmver -ge 10 ]; then %clang -std=c11 -O1 %s -S -emit-llvm -o - %loadClangEnzyme -mllvm -enzyme-inline=1 -S | %lli - ; fi
// RUN: if [ %llvmver -ge 10 ]; then %clang -std=c11 -O2 %s -S -emit-llvm -o - %loadClangEnzyme -mllvm -enzyme-inline=1 -S | %lli - ; fi
// RUN: if [ %llvmver -ge 10 ]; then %clang -std=c11 -O3 %s -S -emit-llvm -o - %loadClangEnzyme -mllvm -enzyme-inline=1 -S | %lli - ; fi
// RUN: if [ %llvmver -ge 12 ]; then %clang -std=c11 -O0 %s -S -emit-llvm -o - %newLoadClangEnzyme | %lli - ; fi
// RUN: if [ %llvmver -ge 12 ]; then %clang -std=c11 -O1 %s -S -emit-llvm -o - %newLoadClangEnzyme | %lli - ; fi
// RUN: if [ %llvmver -ge 12 ]; then %clang -std=c11 -O2 %s -S -emit-llvm -o - %newLoadClangEnzyme | %lli - ; fi
// RUN: if [ %llvmver -ge 12 ]; then %clang -std=c11 -O3 %s -S -emit-llvm -o - %newLoadClangEnzyme | %lli - ; fi
// RUN: if [ %llvmver -ge 12 ]; then %clang -std=c11 -O0 %s -S -emit-llvm -o - %newLoadClangEnzyme -mllvm -enzyme-inline=1 -S | %lli - ; fi
// RUN: if [ %llvmver -ge 12 ]; then %clang -std=c11 -O1 %s -S -emit-llvm -o - %newLoadClangEnzyme -mllvm -enzyme-inline=1 -S | %lli - ; fi
// RUN: if [ %llvmver -ge 12 ]; then %clang -std=c11 -O2 %s -S -emit-llvm -o - %newLoadClangEnzyme -mllvm -enzyme-inline=1 -S | %lli - ; fi
// RUN: if [ %llvmver -ge 12 ]; then %clang -std=c11 -O3 %s -S -emit-llvm -o - %newLoadClangEnzyme -mllvm -enzyme-inline=1 -S | %lli - ; fi

#include <stdio.h>
#include <math.h>
#include <assert.h>

#include "../test_utils.h"

double __enzyme_autodiff(void*, ...);


char buffer[1024];
int offset = 0;
void* myallocator(void* buffer, int size, int* off) {
    char* cur = (char*)buffer;
    int prev = *off;
    *off += size;
    return &cur[prev];
}

static void myfree(int* off, void* tofree) {
    printf("freeing %p and %d\n", tofree, *off);
}

__attribute__((noinline))
double* set(double x) {
    double* m = (double*)myallocator(buffer, sizeof(double), &offset);
    *m = x;
    return m;
}

double test(double a) {
  double* t = set(a);
  return *t;
}

void* __enzyme_allocation_like[4] = {(void*)myallocator, (void*)1, (void*)"2,-1", (void*)myfree}; 

int main(int argc, char** argv) {
  double out = __enzyme_autodiff(test, 2.0); 
  APPROX_EQ(out, 1.0, 1e-10); 
  return 0;
}