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feat: handle -fopenmp #75

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Merged
Arshia001 merged 1 commit into from
Aug 7, 2026
+142 −8
Merged

feat: handle -fopenmp #75

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103 changes: 95 additions & 8 deletions src/compiler.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -96,6 +96,7 @@ pub(crate) struct BuildSettings {
opt_level: OptLevel,
debug_level: DebugLevel,
use_wasm_opt: bool,
openmp: bool,
}

/// A single user-supplied token destined for the link stage. Flags (`-Wl`,
Expand Down Expand Up @@ -266,6 +267,7 @@ pub(crate) fn link_only(args: Vec<String>, mut user_settings: UserSettings) -> R
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: user_settings.run_wasm_opt.unwrap_or(true),
openmp: false,
};

let state = State {
Expand Down Expand Up @@ -553,20 +555,30 @@ fn build_link_args(
push("-lm");
push("-lpthread");
push("-lutil");

if state.cxx || state.user_settings.include_cpp_symbols {
push("-lc++");
push("-lc++abi");
if state.user_settings.wasm_exceptions.is_enabled() {
push("-lunwind");
}
}
}

if matches!(module_kind, ModuleKind::DynamicMain) {
push("--no-whole-archive");
}

// -fopenmp is a compiler-driver flag and cannot be forwarded to wasm-ld.
// The caller supplies libomp's search path just like any other -L path.
if state.build_settings.openmp {
push("-lomp");
}

// The WASIX libomp archive references the C++ runtime. Shared modules do
// not otherwise receive it, and executables should receive only one copy.
if state.build_settings.openmp
|| (module_kind.is_executable() && (state.cxx || state.user_settings.include_cpp_symbols))
{
push("-lc++");
push("-lc++abi");
if state.user_settings.wasm_exceptions.is_enabled() {
push("-lunwind");
}
}

// Link as much as needed out of libclang_rt.builtins regardless of module kind.
push("-lclang_rt.builtins-wasm32");

Expand Down Expand Up @@ -880,6 +892,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
},
args: PreparedArgs {
compiler_args: Vec::new(),
Expand Down Expand Up @@ -907,6 +920,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
},
args: PreparedArgs {
compiler_args: Vec::new(),
Expand Down Expand Up @@ -934,6 +948,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
},
args: PreparedArgs {
compiler_args: Vec::new(),
Expand Down Expand Up @@ -962,6 +977,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
},
args: PreparedArgs {
compiler_args: Vec::new(),
Expand Down Expand Up @@ -989,6 +1005,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
},
args: PreparedArgs {
compiler_args: Vec::new(),
Expand Down Expand Up @@ -1017,6 +1034,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
},
args: PreparedArgs {
compiler_args: Vec::new(),
Expand Down Expand Up @@ -1045,6 +1063,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
},
args: PreparedArgs {
compiler_args: Vec::new(),
Expand Down Expand Up @@ -1076,6 +1095,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
},
args: PreparedArgs {
compiler_args: Vec::new(),
Expand Down Expand Up @@ -1137,6 +1157,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
},
args: PreparedArgs {
compiler_args: Vec::new(),
Expand Down Expand Up @@ -1235,6 +1256,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: false,
openmp: false,
},
args: PreparedArgs {
compiler_args: Vec::new(),
Expand All @@ -1260,6 +1282,23 @@ mod tests {
.collect()
}

fn compiler_args_state(args: &[&str], cxx: bool) -> State {
let mut user_settings = UserSettings::default();
let (args, build_settings) = prepare_compiler_args(
args.iter().map(|arg| (*arg).to_owned()),
&mut user_settings,
cxx,
)
.unwrap();
State {
user_settings,
build_settings,
args,
cxx,
temp_dir: PathBuf::from("/tmp"),
}
}

#[test]
fn test_dynamic_main_user_lib_emitted_after_whole_archive_block() {
// Regression: for DynamicMain, wasixcc force-includes the sysroot libs via
Expand Down Expand Up @@ -1296,6 +1335,54 @@ mod tests {
);
}

#[test]
fn test_openmp_links_runtime_for_shared_module() {
let state = compiler_args_state(&["-fopenmp", "-shared", "ext.o", "-o", "out.wasm"], false);
assert!(state.build_settings.openmp);
let args = rendered_link_args(&state);

for library in ["-lomp", "-lc++", "-lc++abi", "-lunwind"] {
assert_eq!(
args.iter().filter(|arg| arg.as_str() == library).count(),
1,
"OpenMP should link {library} once, got {args:?}"
);
}
}

#[test]
fn test_openmp_cxx_executable_does_not_duplicate_cpp_runtime() {
let mut state = link_args_state(
ModuleKind::StaticMain,
vec![LinkToken::Input(PathBuf::from("main.o"))],
);
state.build_settings.openmp = true;
state.cxx = true;
let args = rendered_link_args(&state);

for library in ["-lomp", "-lc++", "-lc++abi", "-lunwind"] {
assert_eq!(
args.iter().filter(|arg| arg.as_str() == library).count(),
1,
"OpenMP C++ executables should link {library} once, got {args:?}"
);
}
}

#[test]
fn test_no_openmp_leaves_runtime_out() {
let state = link_args_state(
ModuleKind::SharedLibrary,
vec![LinkToken::Input(PathBuf::from("ext.o"))],
);
let args = rendered_link_args(&state);

assert!(
!args.iter().any(|arg| arg == "-lomp"),
"libomp must not be linked without OpenMP, got {args:?}"
);
}

#[test]
fn test_user_whole_archive_bracket_contiguous_in_link_args() {
// A user --whole-archive <archive> --no-whole-archive must reach wasm-ld
Expand Down
47 changes: 47 additions & 0 deletions src/compiler/flags.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -185,6 +185,10 @@ fn update_build_settings_from_compiler_flag(
user_settings.wasm_exceptions = WasmExceptionStyle::Exnref
}
Flag::Simple("-fno-exceptions") => user_settings.wasm_exceptions = WasmExceptionStyle::Off,
// The link stage invokes wasm-ld directly, so remember the compiler
// driver's OpenMP runtime request and translate it in build_link_args.
Flag::Simple("-fopenmp" | "-fopenmp=libomp") => build_settings.openmp = true,
Flag::Simple("-fno-openmp") => build_settings.openmp = false,
Flag::Simple("-fPIC") => user_settings.pic = true,
Flag::Simple("-fno-PIC") => user_settings.pic = false,
Flag::Simple("--wasm-opt") => build_settings.use_wasm_opt = true,
Expand Down Expand Up @@ -455,6 +459,7 @@ pub(super) fn prepare_compiler_args(
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
};

let args = DEFAULT_WASM_CLANG_FLAGS
Expand Down Expand Up @@ -557,6 +562,7 @@ mod tests {
opt_level: OptLevel::O0,
debug_level: DebugLevel::G0,
use_wasm_opt: true,
openmp: false,
};
let mut us = UserSettings::default();
update_build_settings_from_compiler_flag(Flag::Simple("-O3"), &mut bs, &mut us);
Expand All @@ -572,6 +578,11 @@ mod tests {
assert_eq!(us.wasm_exceptions, WasmExceptionStyle::Exnref);
update_build_settings_from_compiler_flag(Flag::Simple("-fno-exceptions"), &mut bs, &mut us);
assert_eq!(us.wasm_exceptions, WasmExceptionStyle::Off);
assert!(!bs.openmp);
update_build_settings_from_compiler_flag(Flag::Simple("-fopenmp"), &mut bs, &mut us);
assert!(bs.openmp);
update_build_settings_from_compiler_flag(Flag::Simple("-fno-openmp"), &mut bs, &mut us);
assert!(!bs.openmp);
us = UserSettings::default();
update_build_settings_from_compiler_flag(
Flag::Simple("-fwasm-exceptions"),
Expand Down Expand Up @@ -643,6 +654,42 @@ mod tests {
assert!(pa.linker_inputs().is_empty());
}

#[test]
fn test_openmp_flags_flow_through_compiler_arg_processing() {
for enable_flag in ["-fopenmp", "-fopenmp=libomp"] {
let mut us = UserSettings::default();
let args = vec![enable_flag.to_string(), "input.o".to_string()];
let (prepared, settings) = prepare_compiler_args(args, &mut us, false).unwrap();

assert!(
settings.openmp,
"{enable_flag} should request the OpenMP runtime"
);
assert!(
prepared.compiler_args.iter().any(|arg| arg == enable_flag),
"{enable_flag} must still reach the compiler frontend"
);
assert_eq!(prepared.linker_inputs(), vec![PathBuf::from("input.o")]);
}

let mut us = UserSettings::default();
let (_, settings) = prepare_compiler_args(
["-fopenmp", "-fno-openmp", "input.o"].map(str::to_string),
&mut us,
false,
)
.unwrap();
assert!(!settings.openmp, "the last OpenMP flag should win");

let (_, settings) = prepare_compiler_args(
["-fno-openmp", "-fopenmp", "input.o"].map(str::to_string),
&mut us,
false,
)
.unwrap();
assert!(settings.openmp, "the last OpenMP flag should win");
}

#[test]
fn test_prepare_compiler_args_lib_flag() {
let mut us = UserSettings::default();
Expand Down
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