fix: Fix compilation issues with PIE

xmnlab · xmnlab · commit 97de020dadf2 · 2026-03-06T17:00:52.000Z
diff --git a/README.md b/README.md
@@ -11,3 +11,30 @@ Arx is a prototype that should replace the current Arx compiler in c++.
 
 If you want more information about ArxLang, please check the original project in
 c++: https://github.com/arxlang/arx
+
+## Link Modes
+
+Arx supports explicit executable link modes:
+
+```bash
+arx program.x --link-mode auto    # default, use toolchain default
+arx program.x --link-mode pie     # force PIE executable
+arx program.x --link-mode no-pie  # force non-PIE executable
+```
+
+## Troubleshooting (PIE / Colab / Conda)
+
+If you hit an error like:
+
+```text
+relocation R_X86_64_32 ... can not be used when making a PIE object
+```
+
+use:
+
+```bash
+arx program.x --link-mode no-pie
+```
+
+This typically happens on environments where the linker defaults to PIE while
+objects were not compiled in a PIE-compatible mode.
diff --git a/docs/getting-started.md b/docs/getting-started.md
@@ -72,6 +72,14 @@ arx --show-llvm-ir hello.x
 arx hello.x --output-file hello
 ```
 
+### Control executable link mode
+
+```bash
+arx examples/print-star.x --link-mode auto
+arx examples/print-star.x --link-mode pie
+arx examples/print-star.x --link-mode no-pie
+```
+
 ## Examples
 
 The `examples/` directory contains several sample programs:
@@ -193,16 +201,40 @@ arx run examples/print-star.x
 arx [input_files] [options]
 ```
 
-| Option           | Description                                      |
-| ---------------- | ------------------------------------------------ |
-| `--version`      | Show the installed version                       |
-| `--output-file`  | Specify the output file path                     |
-| `--lib`          | Build source code as a library                   |
-| `--show-ast`     | Print the AST for the input source code          |
-| `--show-tokens`  | Print the tokens for the input source            |
-| `--show-llvm-ir` | Print the LLVM IR for the input source           |
-| `--run`          | Build and execute the compiled binary            |
-| `--shell`        | Open Arx in a shell prompt (not yet implemented) |
+| Option           | Description                                       |
+| ---------------- | ------------------------------------------------- |
+| `--version`      | Show the installed version                        |
+| `--output-file`  | Specify the output file path                      |
+| `--lib`          | Build source code as a library                    |
+| `--show-ast`     | Print the AST for the input source code           |
+| `--show-tokens`  | Print the tokens for the input source             |
+| `--show-llvm-ir` | Print the LLVM IR for the input source            |
+| `--run`          | Build and execute the compiled binary             |
+| `--shell`        | Open Arx in a shell prompt (not yet implemented)  |
+| `--link-mode`    | Set executable link mode: `auto`, `pie`, `no-pie` |
+
+## Troubleshooting
+
+### PIE linker error in Colab or Conda
+
+If the build fails with an error similar to:
+
+```text
+relocation R_X86_64_32 against `.rodata' can not be used when making a PIE object
+```
+
+run the compile step with:
+
+```bash
+arx average.x --link-mode no-pie
+```
+
+If you need a manual fallback:
+
+```bash
+arx --lib average.x --output-file average.o
+clang -no-pie average.o -o average
+```
 
 ## Language Basics
 
diff --git a/src/arx/cli.py b/src/arx/cli.py
@@ -108,6 +108,16 @@ def get_args() -> argparse.ArgumentParser:
         action="store_true",
         help="Build and run the compiled binary.",
     )
+    parser.add_argument(
+        "--link-mode",
+        type=str,
+        choices=("auto", "pie", "no-pie"),
+        default="auto",
+        help=(
+            "Set executable link mode: auto (toolchain default), "
+            "pie, or no-pie."
+        ),
+    )
 
     return parser
 
diff --git a/src/arx/codegen.py b/src/arx/codegen.py
@@ -7,7 +7,7 @@
 import os
 import tempfile
 
-from typing import Any, Callable
+from typing import Any, Callable, Literal
 
 import astx
 import xh
@@ -37,6 +37,8 @@ class LLVMLiteIR(BaseLLVMLiteIR):
         type: ArxLLVMLiteIRVisitor
     """
 
+    LINK_MODES = {"auto", "pie", "no-pie"}
+
     def __init__(self) -> None:
         """
         title: Initialize LLVMIR.
@@ -45,7 +47,11 @@ def __init__(self) -> None:
         self.translator: ArxLLVMLiteIRVisitor = ArxLLVMLiteIRVisitor()
 
     def build(
-        self, node: astx.AST, output_file: str, link: bool = True
+        self,
+        node: astx.AST,
+        output_file: str,
+        link: bool = True,
+        link_mode: Literal["auto", "pie", "no-pie"] = "auto",
     ) -> None:
         """
         title: >-
@@ -57,6 +63,8 @@ def build(
             type: str
           link:
             type: bool
+          link_mode:
+            type: Literal[auto, pie, no-pie]
         """
         self.translator = ArxLLVMLiteIRVisitor()
         result = self.translator.translate(node)
@@ -78,11 +86,18 @@ def build(
                 file_handler.write(result_object)
             return
 
+        if link_mode not in self.LINK_MODES:
+            raise ValueError(
+                "Invalid link mode. Expected one of: auto, pie, no-pie."
+            )
+
         # fix xh typing
         clang: Callable[..., Any] = xh.clang
-        clang(
-            file_path_o,
-            "-o",
-            self.output_file,
-        )
+        clang_args = [file_path_o]
+        if link_mode == "pie":
+            clang_args.append("-pie")
+        elif link_mode == "no-pie":
+            clang_args.append("-no-pie")
+        clang_args.extend(["-o", self.output_file])
+        clang(*clang_args)
         os.chmod(self.output_file, 0o755)
diff --git a/src/arx/main.py b/src/arx/main.py
@@ -7,7 +7,7 @@
 
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import Any
+from typing import Any, Literal, cast
 
 import astx
 
@@ -40,11 +40,14 @@ class ArxMain:
         type: str
       is_lib:
         type: bool
+      link_mode:
+        type: Literal[auto, pie, no-pie]
     """
 
     input_files: list[str] = field(default_factory=list)
     output_file: str = ""
     is_lib: bool = False
+    link_mode: Literal["auto", "pie", "no-pie"] = "auto"
 
     def _format_ast_fallback(self, node: object) -> str:
         lines: list[str] = []
@@ -181,6 +184,15 @@ def run(self, **kwargs: Any) -> None:
         output_file = kwargs.get("output_file")
         self.output_file = output_file.strip() if output_file else ""
         self.is_lib = kwargs.get("is_lib", False)
+        link_mode = str(kwargs.get("link_mode", "auto")).strip().lower()
+        if link_mode not in {"auto", "pie", "no-pie"}:
+            raise ValueError(
+                "Invalid link mode. Expected one of: auto, pie, no-pie."
+            )
+        self.link_mode = cast(
+            Literal["auto", "pie", "no-pie"],
+            link_mode,
+        )
 
         if kwargs.get("show_ast"):
             return self.show_ast()
@@ -278,5 +290,6 @@ def compile(self, show_llvm_ir: bool = False) -> bool:
             tree_ast,
             output_file=self.output_file,
             link=emits_executable,
+            link_mode=self.link_mode,
         )
         return emits_executable
diff --git a/tests/test_app_paths.py b/tests/test_app_paths.py
@@ -158,13 +158,16 @@ def test_cli_get_args_parsing() -> None:
             "out.o",
             "--lib",
             "--show-tokens",
+            "--link-mode",
+            "no-pie",
         ]
     )
 
     assert args.input_files == ["examples/sum.x"]
     assert args.output_file == "out.o"
     assert args.is_lib is True
     assert args.show_tokens is True
+    assert args.link_mode == "no-pie"
     assert args.run is False
 
 
@@ -194,6 +197,7 @@ def parse_args(self) -> Namespace:
                 version=True,
                 output_file="",
                 is_lib=False,
+                link_mode="auto",
                 show_ast=False,
                 show_tokens=False,
                 show_llvm_ir=False,
@@ -231,6 +235,7 @@ def parse_args(self) -> Namespace:
                 version=False,
                 output_file="out.o",
                 is_lib=True,
+                link_mode="auto",
                 show_ast=False,
                 show_tokens=True,
                 show_llvm_ir=False,
@@ -270,6 +275,7 @@ def parse_args(self) -> Namespace:
                 version=False,
                 output_file="",
                 is_lib=True,
+                link_mode="auto",
                 show_ast=False,
                 show_tokens=False,
                 show_llvm_ir=False,
@@ -508,23 +514,27 @@ class DummyIRBuild:
         built_tree: object | None = None
         built_out: str | None = None
         built_link: bool | None = None
+        built_link_mode: str | None = None
 
         def build(
             self,
             tree: object,
             output_file: str = "",
             link: bool = True,
+            link_mode: str = "auto",
         ) -> None:
             DummyIRBuild.built_tree = tree
             DummyIRBuild.built_out = output_file
             DummyIRBuild.built_link = link
+            DummyIRBuild.built_link_mode = link_mode
 
     monkeypatch.setattr(main_module, "LLVMLiteIR", DummyIRBuild)
     monkeypatch.setattr(app, "_get_astx", fake_get_astx_tree)
     app.compile()
     assert DummyIRBuild.built_tree is not None
     assert DummyIRBuild.built_out == "out.o"
     assert DummyIRBuild.built_link is False
+    assert DummyIRBuild.built_link_mode == "auto"
 
 
 def test_arxmain_compile_default_output_name(
@@ -544,16 +554,19 @@ def fake_get_astx_tree() -> object:
     class DummyIRBuild:
         built_out: str | None = None
         built_link: bool | None = None
+        built_link_mode: str | None = None
 
         def build(
             self,
             tree: object,
             output_file: str = "",
             link: bool = True,
+            link_mode: str = "auto",
         ) -> None:
             del tree
             DummyIRBuild.built_out = output_file
             DummyIRBuild.built_link = link
+            DummyIRBuild.built_link_mode = link_mode
 
     monkeypatch.setattr(app, "_get_astx", fake_get_astx_tree)
     monkeypatch.setattr(main_module, "LLVMLiteIR", DummyIRBuild)
@@ -562,6 +575,7 @@ def build(
 
     assert DummyIRBuild.built_out == "print-star"
     assert DummyIRBuild.built_link is False
+    assert DummyIRBuild.built_link_mode == "auto"
     assert app.output_file == "print-star"
 
 
@@ -581,15 +595,18 @@ def fake_get_astx_tree() -> object:
 
     class DummyIRBuild:
         built_link: bool | None = None
+        built_link_mode: str | None = None
 
         def build(
             self,
             tree: object,
             output_file: str = "",
             link: bool = True,
+            link_mode: str = "auto",
         ) -> None:
             del tree, output_file
             DummyIRBuild.built_link = link
+            DummyIRBuild.built_link_mode = link_mode
 
     def fake_has_main_entry(node: object) -> bool:
         del node
@@ -602,6 +619,7 @@ def fake_has_main_entry(node: object) -> bool:
     app.compile()
 
     assert DummyIRBuild.built_link is True
+    assert DummyIRBuild.built_link_mode == "auto"
 
 
 def test_arxmain_run_requires_executable_for_run_flag(
