From 715e5d8035659bfa91ddc4805748d05744bf6553 Mon Sep 17 00:00:00 2001
From: Thomas Lively <tlively@google.com>
Date: Thu, 3 Oct 2019 16:42:23 -0700
Subject: [PATCH] Mark Emscripten's .wasm files auxiliary

This fixes #7471 and fixes #7255 by preventing the .wasm file from
being treated as an executable binary, so `cargo test` and `cargo run`
will no longer try to execute it directly. This change is only made
for emscripten, which outputs a .js file as the primary executable
entry point, as opposed to other WebAssembly targets for which the
.wasm file is the only output.
---
 src/cargo/core/compiler/build_context/target_info.rs | 9 ++++++++-
 src/cargo/core/compiler/context/mod.rs               | 3 ++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/cargo/core/compiler/build_context/target_info.rs b/src/cargo/core/compiler/build_context/target_info.rs
index 926a1ca9664..61bbb365dfc 100644
--- a/src/cargo/core/compiler/build_context/target_info.rs
+++ b/src/cargo/core/compiler/build_context/target_info.rs
@@ -42,6 +42,8 @@ pub struct TargetInfo {
 pub enum FileFlavor {
     /// Not a special file type.
     Normal,
+    /// Like `Normal`, but not directly executable
+    Auxiliary,
     /// Something you can link against (e.g., a library).
     Linkable { rmeta: bool },
     /// Piece of external debug information (e.g., `.dSYM`/`.pdb` file).
@@ -253,10 +255,15 @@ impl TargetInfo {
 
         // See rust-lang/cargo#4535.
         if target_triple.starts_with("wasm32-") && crate_type == "bin" && suffix == ".js" {
+            let flavor = if target_triple.contains("emscripten") {
+                FileFlavor::Auxiliary
+            } else {
+                FileFlavor::Normal
+            };
             ret.push(FileType {
                 suffix: ".wasm".to_string(),
                 prefix: prefix.clone(),
-                flavor: FileFlavor::Normal,
+                flavor,
                 should_replace_hyphens: true,
             })
         }
diff --git a/src/cargo/core/compiler/context/mod.rs b/src/cargo/core/compiler/context/mod.rs
index db5ea9eca17..55f2a4fb354 100644
--- a/src/cargo/core/compiler/context/mod.rs
+++ b/src/cargo/core/compiler/context/mod.rs
@@ -167,7 +167,8 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
 
         for unit in units.iter() {
             for output in self.outputs(unit)?.iter() {
-                if output.flavor == FileFlavor::DebugInfo {
+                if output.flavor == FileFlavor::DebugInfo ||
+                    output.flavor == FileFlavor::Auxiliary {
                     continue;
                 }