Explain why we're sorting the modules.

Joel Galenson · Joel Galenson · commit 3e6a9273057a · 2019-08-08T10:51:52.000-07:00
diff --git a/src/librustc_codegen_llvm/back/lto.rs b/src/librustc_codegen_llvm/back/lto.rs
@@ -278,6 +278,7 @@ fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
                 }
             }
         }).collect::<Vec<_>>();
+        // Sort the modules to ensure we produce deterministic results.
         new_modules.sort_by(|module1, module2| module1.1.partial_cmp(&module2.1).unwrap());
         serialized_modules.extend(new_modules);
         serialized_modules.extend(cached_modules.into_iter().map(|(buffer, wp)| {

Original file line number	Diff line number	Diff line change
`@@ -278,6 +278,7 @@ fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,`
`278`	`278`	`}`
`279`	`279`	`}`
`280`	`280`	`}).collect::<Vec<_>>();`
	`281`	`+ // Sort the modules to ensure we produce deterministic results.`
`281`	`282`	`new_modules.sort_by(\|module1, module2\| module1.1.partial_cmp(&module2.1).unwrap());`
`282`	`283`	`serialized_modules.extend(new_modules);`
`283`	`284`	`serialized_modules.extend(cached_modules.into_iter().map(\|(buffer, wp)\| {`