fix: calculate windows dll symbols from prebuilt shared library

crates/cli/src/main.rs

@@ -169,11 +169,6 @@ fn main() -> io::Result<()> {
 
             let verbose_and_time = matches.get_one::<bool>(roc_cli::FLAG_VERBOSE).unwrap();
 
-            #[cfg(target_os = "windows")]
-            {
-                internal_error!("TODO populate stub_dll_symbols for Windows");
-            }
-
             roc_linker::preprocess_host(
                 target,
                 host_path,

crates/linker/src/elf.rs

@@ -15,9 +15,10 @@ use std::{
     io::{BufReader, BufWriter},
     mem,
     path::Path,
-    time::{Duration, Instant},
+    time::Instant,
 };
 
+use crate::util::{is_roc_definition, is_roc_undefined, report_timing};
 use crate::{
     align_by_constraint, align_to_offset_by_constraint, load_struct_inplace,
     load_struct_inplace_mut, load_structs_inplace_mut, open_mmap, open_mmap_mut,
@@ -103,26 +104,6 @@ impl Metadata {
     }
 }
 
-fn report_timing(label: &str, duration: Duration) {
-    println!("\t{:9.3} ms   {}", duration.as_secs_f64() * 1000.0, label,);
-}
-
-fn is_roc_symbol(sym: &object::Symbol) -> bool {
-    if let Ok(name) = sym.name() {
-        name.trim_start_matches('_').starts_with("roc_")
-    } else {
-        false
-    }
-}
-
-fn is_roc_definition(sym: &object::Symbol) -> bool {
-    sym.is_definition() && is_roc_symbol(sym)
-}
-
-fn is_roc_undefined(sym: &object::Symbol) -> bool {
-    sym.is_undefined() && is_roc_symbol(sym)
-}
-
 fn collect_roc_definitions<'a>(object: &object::File<'a, &'a [u8]>) -> MutMap<String, u64> {
     let mut vaddresses = MutMap::default();
 

crates/linker/src/lib.rs

@@ -19,6 +19,7 @@ use std::path::{Path, PathBuf};
 mod elf;
 mod macho;
 mod pe;
+mod util;
 
 mod generate_dylib;
 
@@ -380,7 +381,6 @@ pub fn preprocess_host(
         &metadata_path,
         preprocessed_path.as_path(),
         dylib_path,
-        &[],
         verbose,
         time,
     )
@@ -394,7 +394,6 @@ fn preprocess(
     metadata_path: &Path,
     preprocessed_path: &Path,
     shared_lib: &Path,
-    stub_dll_symbols: &[String],
     verbose: bool,
     time: bool,
 ) {
@@ -430,7 +429,7 @@ fn preprocess(
                 host_exe_path,
                 metadata_path,
                 preprocessed_path,
-                stub_dll_symbols,
+                shared_lib,
                 verbose,
                 time,
             )

crates/linker/src/pe.rs

@@ -11,7 +11,7 @@ use object::{
         ImageSectionHeader, ImageThunkData64,
     },
     read::pe::ImportTable,
-    LittleEndian as LE, Object, RelocationTarget, SectionIndex,
+    LittleEndian as LE, Object, ObjectSection, ObjectSymbol, RelocationTarget, SectionIndex,
 };
 use serde::{Deserialize, Serialize};
 
@@ -19,8 +19,10 @@ use roc_collections::{MutMap, VecMap};
 use roc_error_macros::internal_error;
 
 use crate::{
-    generate_dylib::APP_DLL, load_struct_inplace, load_struct_inplace_mut,
-    load_structs_inplace_mut, open_mmap, open_mmap_mut,
+    generate_dylib::APP_DLL,
+    load_struct_inplace, load_struct_inplace_mut, load_structs_inplace_mut, open_mmap,
+    open_mmap_mut,
+    util::is_roc_definition,
 };
 
 /// The metadata stores information about/from the host .exe because
@@ -95,8 +97,6 @@ impl PeMetadata {
     }
 
     fn from_preprocessed_host(preprocessed_data: &[u8], new_sections: &[[u8; 8]]) -> Self {
-        use object::ObjectSection;
-
         let dynhost_obj = object::read::pe::PeFile64::parse(preprocessed_data)
             .unwrap_or_else(|err| internal_error!("Failed to parse executable file: {}", err));
 
@@ -183,17 +183,26 @@ pub(crate) fn preprocess_windows(
     host_exe_filename: &Path,
     metadata_filename: &Path,
     preprocessed_filename: &Path,
-    dummy_dll_symbols: &[String],
+    shared_lib: &Path,
     _verbose: bool,
     _time: bool,
 ) -> object::read::Result<()> {
-    let data = open_mmap(host_exe_filename);
+    let exec_data = open_mmap(host_exe_filename);
+    let shared_lib_data = &*open_mmap(shared_lib);
+    let shared_lib_obj = match object::File::parse(shared_lib_data) {
+        Ok(obj) => obj,
+        Err(e) => internal_error!("Failed to parse shared library file: {e}"),
+    };
+    let dummy_dll_symbols = shared_lib_obj
+        .dynamic_symbols()
+        .filter(is_roc_definition)
+        .count();
 
     let new_sections = [*b".text\0\0\0", *b".rdata\0\0"];
     let mut preprocessed = Preprocessor::preprocess(
         preprocessed_filename,
-        &data,
-        dummy_dll_symbols.len(),
+        &exec_data,
+        dummy_dll_symbols,
         &new_sections,
     );
 
@@ -1164,8 +1173,6 @@ fn process_internal_relocations(
 
 impl<'a> AppSections<'a> {
     fn from_data(data: &'a [u8]) -> Self {
-        use object::ObjectSection;
-
         let file = object::File::parse(data).unwrap();
 
         let mut sections = Vec::new();
@@ -1193,8 +1200,6 @@ impl<'a> AppSections<'a> {
             for (offset_in_section, relocation) in section.relocations() {
                 match relocation.target() {
                     RelocationTarget::Symbol(symbol_index) => {
-                        use object::ObjectSymbol;
-
                         let symbol = file.symbol_by_index(symbol_index);
 
                         let address = symbol.as_ref().map(|s| s.address()).unwrap_or_default();
@@ -1252,8 +1257,6 @@ impl<'a> AppSections<'a> {
         let mut other_symbols = Vec::new();
 
         for symbol in file.symbols() {
-            use object::ObjectSymbol;
-
             if symbol.name_bytes().unwrap_or_default().starts_with(b"roc") {
                 if let object::SymbolSection::Section(index) = symbol.section() {
                     let (kind, offset_in_host_section) = section_starts[&index];
@@ -1801,7 +1804,7 @@ mod test {
             &dir.join("host.exe"),
             &dir.join("metadata"),
             &preprocessed_host_filename,
-            &names,
+            &dir.join("libapp.dll"),
             false,
             false,
         )

crates/linker/src/util.rs

@@ -0,0 +1,23 @@
+use std::time::Duration;
+
+use object::ObjectSymbol;
+
+pub(crate) fn report_timing(label: &str, duration: Duration) {
+    println!("\t{:9.3} ms   {}", duration.as_secs_f64() * 1000.0, label,);
+}
+
+fn is_roc_symbol(sym: &object::Symbol) -> bool {
+    if let Ok(name) = sym.name() {
+        name.trim_start_matches('_').starts_with("roc_")
+    } else {
+        false
+    }
+}
+
+pub(crate) fn is_roc_definition(sym: &object::Symbol) -> bool {
+    sym.is_definition() && is_roc_symbol(sym)
+}
+
+pub(crate) fn is_roc_undefined(sym: &object::Symbol) -> bool {
+    sym.is_undefined() && is_roc_symbol(sym)
+}