Extern functions and basic C ABI support

src/LLVM.zig

@@ -677,6 +677,8 @@ pub const Builder = opaque {
     pub fn create_sign_extend(builder: *Builder, value: *Value, destination_type: *Type) *Value {
         return api.LLVMBuildSExt(builder, value, destination_type, "");
     }
+
+    pub const create_unreachable = api.LLVMBuildUnreachable;
 };
 
 pub const GlobalValue = opaque {

src/converter_test.zig

@@ -58,6 +58,7 @@ fn unit_test(allocator: std.mem.Allocator, options: InvokeWrapper) !void {
         .build_mode = options.build_mode,
         .name = options.name,
         .has_debug_info = options.has_debug_info,
+        .target = converter.Target.get_native(),
     });
     const run_result = std.process.Child.run(.{
         .allocator = allocator,
@@ -172,3 +173,7 @@ test "bits" {
 test "basic_array" {
     try invsrc(@src());
 }
+
+test "extern" {
+    try invsrc(@src());
+}

src/llvm_api.zig

@@ -57,6 +57,7 @@ pub extern fn LLVMBuildInBoundsGEP2(builder: *llvm.Builder, ty: *llvm.Type, aggr
 pub extern fn LLVMBuildInsertValue(builder: *llvm.Builder, aggregate: *llvm.Value, element: *llvm.Value, index: c_uint, name: [*:0]const u8) *llvm.Value;
 pub extern fn LLVMBuildZExt(builder: *llvm.Builder, value: *llvm.Value, destination_type: *llvm.Type, name: [*:0]const u8) *llvm.Value;
 pub extern fn LLVMBuildSExt(builder: *llvm.Builder, value: *llvm.Value, destination_type: *llvm.Type, name: [*:0]const u8) *llvm.Value;
+pub extern fn LLVMBuildUnreachable(builder: *llvm.Builder) *llvm.Value;
 
 pub extern fn LLVMSetCurrentDebugLocation2(builder: *llvm.Builder, location: ?*llvm.DI.Location) void;
 

src/main.zig

@@ -182,6 +182,7 @@ pub fn main(argc: c_int, argv: [*:null]const ?[*:0]const u8) callconv(.C) c_int
         .content = file_content,
         .path = file_path,
         .has_debug_info = true,
+        .target = converter.Target.get_native(),
     });
     return 0;
 }

tests/extern.bbb

@@ -0,0 +1,5 @@
+[extern] exit = fn [cc(c)] (exit_code: s32) noreturn;
+[export] main = fn [cc(c)] () s32
+{
+    exit(0);
+}