add test that combines a zig platform with a dll

crates/linker/src/pe.rs

@@ -398,6 +398,8 @@ mod test {
     use object::read::pe::PeFile64;
     use object::{pe, Object};
 
+    use indoc::indoc;
+
     use super::*;
 
     #[test]
@@ -574,27 +576,23 @@ mod test {
         assert_eq!(actual, 7)
     }
 
-    #[test]
-    fn increase_number_of_sections() {
+    fn increase_number_of_sections_help(input_data: &[u8], output_file: &Path) {
         use object::read::pe::ImageNtHeaders;
 
-        let dos_header = pe::ImageDosHeader::parse(PE_DYNHOST).unwrap();
+        let dos_header = pe::ImageDosHeader::parse(input_data).unwrap();
         let mut offset = dos_header.nt_headers_offset().into();
         let header_offset = offset;
         let number_of_sections_offset = header_offset + 4 + 2;
 
         let sections_len_old = u16::from_le_bytes(
-            PE_DYNHOST[number_of_sections_offset as usize..][..2]
+            input_data[number_of_sections_offset as usize..][..2]
                 .try_into()
                 .unwrap(),
         );
 
         let new_sections = [*b"placehol", *b"aaaabbbb"];
 
-        let dir = tempfile::tempdir().unwrap();
-        let path = dir.path().join("test.exe");
-
-        let mmap = Preprocessor::preprocess(&path, PE_DYNHOST, &new_sections);
+        let mmap = Preprocessor::preprocess(output_file, input_data, &new_sections);
 
         let data = mmap.deref();
 
@@ -622,61 +620,53 @@ mod test {
         assert_eq!(new_sections, names.as_slice());
     }
 
+    #[test]
+    fn increase_number_of_sections() {
+        let dir = tempfile::tempdir().unwrap();
+        let path = dir.path().join("test.exe");
+
+        increase_number_of_sections_help(PE_DYNHOST, &path);
+    }
+
     #[test]
     fn preprocess_zig_host() {
-        let host_zig = include_str!("../trivial_host.zig");
-        let app_zig = include_str!("../trivial_app.zig");
+        let host_zig = indoc!(
+            r#"
+            extern fn double(u8) u8;
+
+            pub fn main() u8 {
+                return double(42);
+            }
+            "#
+        );
+
+        let app_zig = indoc!(
+            r#"
+            export fn double(n: u8) u8 {
+                return n + n;
+            }
+            "#
+        );
 
         let zig = std::env::var("ROC_ZIG").unwrap_or_else(|_| "zig".into());
 
         let dir = tempfile::tempdir().unwrap();
         let dir = dir.path();
 
-        std::fs::write(dir.join("trivial_host.zig"), host_zig.as_bytes()).unwrap();
-        std::fs::write(dir.join("trivial_app.zig"), app_zig.as_bytes()).unwrap();
+        std::fs::write(dir.join("host.zig"), host_zig.as_bytes()).unwrap();
+        std::fs::write(dir.join("app.zig"), app_zig.as_bytes()).unwrap();
 
-        // here we would like to do
-        //
-        // let dylib_bytes = crate::generate_dylib::synthetic_dll(&["double".into(), "triple".into()]);
-        // std::fs::write(dir.join("roc-cheaty-lib.dll"), dylib_bytes).unwrap();
-        //
-        // but on windows, this is not so simple. To link a .dll into an .exe we need an additional
-        // .lib file, a so-called "import library". These are normally generated by the linker, and
-        // based on some googling there is other tooling on windows that can also generate them
-        // from a .dll. There is however very little information on what they should contain.
-        //
-        // Jakub intends to implement generating the .lib files in pure zig in the near(ish)
-        // future, so if we can wait then we can use the zig source to create our own logic for
-        // a very simple .lib file
-
-        let output = std::process::Command::new(&zig)
-            .current_dir(dir)
-            .args(&[
-                "build-lib",
-                "trivial_app.zig",
-                "-target",
-                "x86_64-windows-gnu",
-                "--strip",
-                "-OReleaseFast",
-            ])
-            .output()
-            .unwrap();
-
-        if !output.status.success() {
-            use std::io::Write;
-
-            std::io::stdout().write_all(&output.stdout).unwrap();
-            std::io::stderr().write_all(&output.stderr).unwrap();
-
-            panic!();
-        }
+        let dylib_bytes = crate::generate_dylib::synthetic_dll(&["double".into()]);
+        std::fs::write(dir.join("libapp.obj"), dylib_bytes).unwrap();
 
         let output = std::process::Command::new(&zig)
             .current_dir(dir)
             .args(&[
                 "build-exe",
-                "trivial_host.zig",
-                "trivial_app.lib",
+                "-fPIE",
+                "libapp.obj",
+                "host.zig",
+                "-lc",
                 "-target",
                 "x86_64-windows-gnu",
                 "--strip",
@@ -691,7 +681,32 @@ mod test {
             std::io::stdout().write_all(&output.stdout).unwrap();
             std::io::stderr().write_all(&output.stderr).unwrap();
 
-            panic!();
+            panic!("zig build-exe failed");
+        }
+
+        let data = std::fs::read(dir.join("host.exe")).unwrap();
+        increase_number_of_sections_help(&data, &dir.join("dynhost.exe"));
+
+        let output = std::process::Command::new(&zig)
+            .current_dir(dir)
+            .args(&[
+                "build-obj",
+                "app.zig",
+                "-target",
+                "x86_64-windows-gnu",
+                "--strip",
+                "-OReleaseFast",
+            ])
+            .output()
+            .unwrap();
+
+        if !output.status.success() {
+            use std::io::Write;
+
+            std::io::stdout().write_all(&output.stdout).unwrap();
+            std::io::stderr().write_all(&output.stderr).unwrap();
+
+            panic!("zig build-obj failed");
         }
     }
 }