Get lib example working, create build script (#55104)

Note this is a PR against #55047

Co-authored by: Gabriel Baraldi <baraldigabriel@gmail.com>

juliac/lib_examples/linsolve/Project.toml

@@ -0,0 +1,9 @@
+[deps]
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
+OpenBLAS_jll = "4536629a-c528-5b80-bd46-f80d51c5b363"
+PrecompileTools = "aea7be01-6a6a-4083-8856-8a6e6704d82a"
+RecursiveFactorization = "f2c3362d-daeb-58d1-803e-2bc74f2840b4"
+SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
+Static = "aedffcd0-7271-4cad-89d0-dc628f76c6d3"
+StrideArraysCore = "7792a7ef-975c-4747-a70f-980b88e8d1da"

juliac/lib_examples/linsolve/build.sh

@@ -0,0 +1,12 @@
+#! /bin/bash
+if [ ! -f Manifest.toml ]; then
+    echo "Instantiating package environment..."
+    ../../../julia --project -e 'using Pkg; Pkg.instantiate()'
+    echo "done"
+fi
+echo "Building library..."
+../../../julia --project ../../juliac.jl --output-lib liblinsolve --compile-ccallable --static-call-graph liblinsolve.jl
+echo "done"
+echo "Linking C main..."
+gcc -o linsolve10 -L. -Wl,-rpath,\$ORIGIN ../../test/test.c -llinsolve
+echo "done"

juliac/lib_examples/linsolve/liblinsolve.jl

@@ -0,0 +1,13 @@
+module Lib
+
+using LinearAlgebra
+
+Base.@ccallable function linsolve10(A_ptr::Ptr{Float64}, b_ptr::Ptr{Float64}, N::Csize_t)::Ptr{Float64}
+    A = unsafe_wrap(Array, A_ptr, (N,N)) 
+    b = unsafe_wrap(Array, b_ptr, N)    
+    F = lu!(A)
+    ldiv!(F, b)
+    return b_ptr
+end
+
+end

juliac/test/test.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 
-double* linsolve10(double *A, double *b);
+double* linsolve10(double * A, double * b, size_t N);
+
 int main() {
     // Declare a 10x10 matrix
     double A[10][10] = {
@@ -27,7 +28,7 @@ int main() {
  -10.107200370651855,
    0.8478731362967014};
 
-    linsolve10(A, b);
+    linsolve10((double*)A, (double*)b, 10);
     for (int i = 0; i < 10; i++) {
         printf("%f\n", b[i]);
     }