repl_test: update build.rs to work with Zig 0.9 (like test_gen)

compiler/gen_wasm/src/wasm_module/sections.rs

@@ -115,7 +115,7 @@ fn section_size(bytes: &[u8]) -> usize {
 }
 
 fn parse_section<'a>(id: SectionId, module_bytes: &'a [u8], cursor: &mut usize) -> (u32, &'a [u8]) {
-    if module_bytes[*cursor] != id as u8 {
+    if (*cursor >= module_bytes.len()) || (module_bytes[*cursor] != id as u8) {
         return (0, &[]);
     }
     *cursor += 1;

compiler/test_gen/build.rs

@@ -39,13 +39,13 @@ fn build_wasm() {
         &platform_path,
         &compiler_rt_path,
         "-L",
-        &libc_dir,
+        libc_dir,
         "-lc",
         "-o",
         &format!("{}/{}.o", out_dir, PLATFORM_FILENAME),
         "--export-all",
         "--no-entry",
-        // "--emit-relocs", // TODO: resize stack by relocating __heap_base (issue #2480)
+        // "--emit-relocs", // TODO: resize stack by relocating __heap_base (issue #2480) here and in repl_test build
     ];
 
     let zig = zig_executable();

repl_wasm/build.rs

@@ -1,6 +1,6 @@
 use std::env;
 use std::ffi::OsStr;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::process::Command;
 
 use roc_builtins::bitcode;
@@ -10,7 +10,8 @@ const PRE_LINKED_BINARY: &str = "data/pre_linked_binary.o";
 
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-changed=src/{}.c", PLATFORM_FILENAME);
+    let source_path = format!("src/{}.c", PLATFORM_FILENAME);
+    println!("cargo:rerun-if-changed={}", source_path);
 
     // When we build on Netlify, zig is not installed (but also not used,
     // since all we're doing is generating docs), so we can skip the steps
@@ -23,26 +24,38 @@ fn main() {
 
     std::fs::create_dir_all("./data").unwrap();
 
-    // Build a pre-linked binary with platform, builtins and all their libc dependencies
-    // This builds a library file that exports all symbols. It has no linker data but we don't need it.
-    // See discussion with Luuk de Gram (Zig contributor)
-    // https://github.com/rtfeldman/roc/pull/2181#pullrequestreview-839608063
-    let args = [
-        "build-lib",
-        "-target",
-        "wasm32-wasi",
-        "-lc",
-        "-dynamic", // -dynamic ensures libc code goes into the binary
+    // Zig can produce *either* an object containing relocations OR an object containing libc code
+    // But we want both, so we have to compile twice with different flags, then link them
+
+    // Create an object file with relocations
+    let out_dir = env::var("OUT_DIR").unwrap();
+    let platform_obj = build_wasm_platform(&out_dir, &source_path);
+
+    // Compile again to get libc path
+    let (libc_archive, compiler_rt_obj) = build_wasm_libc_compilerrt(&out_dir, &source_path);
+    let mut libc_pathbuf = PathBuf::from(&libc_archive);
+    libc_pathbuf.pop();
+    let libc_dir = libc_pathbuf.to_str().unwrap();
+
+    let args = &[
+        "wasm-ld",
         bitcode::BUILTINS_WASM32_OBJ_PATH,
-        &format!("src/{}.c", PLATFORM_FILENAME),
-        &format!("-femit-bin={}", PRE_LINKED_BINARY),
+        &platform_obj,
+        &compiler_rt_obj,
+        "-L",
+        libc_dir,
+        "-lc",
+        "-o",
+        PRE_LINKED_BINARY,
+        "--export-all",
+        "--no-entry",
     ];
 
     let zig = zig_executable();
 
     // println!("{} {}", zig, args.join(" "));
 
-    run_command(Path::new("."), &zig, args);
+    run_command(&zig, args);
 }
 
 fn zig_executable() -> String {
@@ -52,26 +65,77 @@ fn zig_executable() -> String {
     }
 }
 
-fn run_command<S, I, P: AsRef<Path>>(path: P, command_str: &str, args: I) -> String
-where
-    I: IntoIterator<Item = S>,
-    S: AsRef<OsStr>,
-{
+fn build_wasm_platform(out_dir: &str, source_path: &str) -> String {
+    let platform_obj = format!("{}/{}.o", out_dir, PLATFORM_FILENAME);
+
+    run_command(
+        &zig_executable(),
+        &[
+            "build-lib",
+            "-target",
+            "wasm32-wasi",
+            "-lc",
+            source_path,
+            &format!("-femit-bin={}", &platform_obj),
+        ],
+    );
+
+    platform_obj
+}
+
+fn build_wasm_libc_compilerrt(out_dir: &str, source_path: &str) -> (String, String) {
+    let zig_cache_dir = format!("{}/zig-cache-wasm32", out_dir);
+
+    run_command(
+        &zig_executable(),
+        &[
+            "build-lib",
+            "-dynamic", // ensure libc code is actually generated (not just linked against header)
+            "-target",
+            "wasm32-wasi",
+            "-lc",
+            source_path,
+            "-femit-bin=/dev/null",
+            "--global-cache-dir",
+            &zig_cache_dir,
+        ],
+    );
+
+    (
+        run_command("find", &[&zig_cache_dir, "-name", "libc.a"]),
+        run_command("find", &[&zig_cache_dir, "-name", "compiler_rt.o"]),
+    )
+}
+
+fn run_command(command_str: &str, args: &[&str]) -> String {
     let output_result = Command::new(OsStr::new(&command_str))
-        .current_dir(path)
+        .current_dir(Path::new("."))
         .args(args)
         .output();
+
+    let fail = |err: String| {
+        panic!(
+            "\n\nFailed command:\n\t{} {}\n\n{}",
+            command_str,
+            args.join(" "),
+            err
+        );
+    };
+
     match output_result {
         Ok(output) => match output.status.success() {
-            true => std::str::from_utf8(&output.stdout).unwrap().to_string(),
+            true => std::str::from_utf8(&output.stdout)
+                .unwrap()
+                .trim()
+                .to_string(),
             false => {
                 let error_str = match std::str::from_utf8(&output.stderr) {
                     Ok(stderr) => stderr.to_string(),
                     Err(_) => format!("Failed to run \"{}\"", command_str),
                 };
-                panic!("{} failed: {}", command_str, error_str);
+                fail(error_str)
             }
         },
-        Err(reason) => panic!("{} failed: {}", command_str, reason),
+        Err(reason) => fail(reason.to_string()),
     }
 }