Merge branch 'master' into rusty-hermit

src/librustc_target/abi/mod.rs

@@ -738,7 +738,11 @@ impl FieldPlacement {
 
     pub fn offset(&self, i: usize) -> Size {
         match *self {
-            FieldPlacement::Union(_) => Size::ZERO,
+            FieldPlacement::Union(count) => {
+                assert!(i < count,
+                        "Tried to access field {} of union with {} fields", i, count);
+                Size::ZERO
+            },
             FieldPlacement::Array { stride, count } => {
                 let i = i as u64;
                 assert!(i < count);

src/librustc_target/spec/mod.rs

@@ -691,6 +691,9 @@ pub struct TargetOptions {
     /// defined in libgcc. If this option is enabled, the target must provide
     /// `eh_unwind_resume` lang item.
     pub custom_unwind_resume: bool,
+    /// Whether the runtime startup code requires the `main` function be passed
+    /// `argc` and `argv` values.
+    pub main_needs_argc_argv: bool,
 
     /// Flag indicating whether ELF TLS (e.g., #[thread_local]) is available for
     /// this target.
@@ -849,6 +852,7 @@ impl Default for TargetOptions {
             link_env_remove: Vec::new(),
             archive_format: "gnu".to_string(),
             custom_unwind_resume: false,
+            main_needs_argc_argv: true,
             allow_asm: true,
             has_elf_tls: false,
             obj_is_bitcode: false,
@@ -1159,6 +1163,7 @@ impl Target {
         key!(archive_format);
         key!(allow_asm, bool);
         key!(custom_unwind_resume, bool);
+        key!(main_needs_argc_argv, bool);
         key!(has_elf_tls, bool);
         key!(obj_is_bitcode, bool);
         key!(no_integrated_as, bool);
@@ -1376,6 +1381,7 @@ impl ToJson for Target {
         target_option_val!(archive_format);
         target_option_val!(allow_asm);
         target_option_val!(custom_unwind_resume);
+        target_option_val!(main_needs_argc_argv);
         target_option_val!(has_elf_tls);
         target_option_val!(obj_is_bitcode);
         target_option_val!(no_integrated_as);

src/librustc_target/spec/wasm32_wasi.rs

@@ -101,6 +101,10 @@ pub fn target() -> Result<Target, String> {
     // without a main function.
     options.crt_static_allows_dylibs = true;
 
+    // WASI's `sys::args::init` function ignores its arguments; instead,
+    // `args::args()` makes the WASI API calls itself.
+    options.main_needs_argc_argv = false;
+
     Ok(Target {
         llvm_target: "wasm32-wasi".to_string(),
         target_endian: "little".to_string(),