diff options
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/back/linker.rs | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs index 4dd688c2234..b13d7d8616a 100644 --- a/compiler/rustc_codegen_ssa/src/back/linker.rs +++ b/compiler/rustc_codegen_ssa/src/back/linker.rs @@ -1302,6 +1302,8 @@ impl<'a> Linker for WasmLd<'a> { } fn optimize(&mut self) { + // The -O flag is, as of late 2023, only used for merging of strings and debuginfo, and + // only differentiates -O0 and -O1. It does not apply to LTO. self.cmd.arg(match self.sess.opts.optimize { OptLevel::No => "-O0", OptLevel::Less => "-O1", @@ -1354,7 +1356,31 @@ impl<'a> Linker for WasmLd<'a> { fn subsystem(&mut self, _subsystem: &str) {} fn linker_plugin_lto(&mut self) { - // Do nothing for now + match self.sess.opts.cg.linker_plugin_lto { + LinkerPluginLto::Disabled => { + // Nothing to do + } + LinkerPluginLto::LinkerPluginAuto => { + self.push_linker_plugin_lto_args(); + } + LinkerPluginLto::LinkerPlugin(_) => { + self.push_linker_plugin_lto_args(); + } + } + } +} + +impl<'a> WasmLd<'a> { + fn push_linker_plugin_lto_args(&mut self) { + let opt_level = match self.sess.opts.optimize { + config::OptLevel::No => "O0", + config::OptLevel::Less => "O1", + config::OptLevel::Default => "O2", + config::OptLevel::Aggressive => "O3", + // wasm-ld only handles integer LTO opt levels. Use O2 + config::OptLevel::Size | config::OptLevel::SizeMin => "O2", + }; + self.cmd.arg(&format!("--lto-{opt_level}")); } } |