Auto merge of #90382 - alexcrichton:wasm64-libstd, r=joshtriplett

std: Get the standard library compiling for wasm64

This commit goes through and updates various `#[cfg]` as appropriate to
get the wasm64-unknown-unknown target behaving similarly to the
wasm32-unknown-unknown target. Most of this is just updating various
conditions for `target_arch = "wasm32"` to also account for `target_arch
= "wasm64"` where appropriate. This commit also lists `wasm64` as an
allow-listed architecture to not have the `restricted_std` feature
enabled, enabling experimentation with `-Z build-std` externally.

The main goal of this commit is to enable playing around with
`wasm64-unknown-unknown` externally via `-Z build-std` in a way that's
similar to the `wasm32-unknown-unknown` target. These targets are
effectively the same and only differ in their pointer size, but wasm64
is much newer and has much less ecosystem/library support so it'll still
take time to get wasm64 fully-fledged.

compiler/rustc_codegen_llvm/src/asm.rs

@@ -320,7 +320,7 @@ impl AsmBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
                 InlineAsmArch::Mips | InlineAsmArch::Mips64 => {}
                 InlineAsmArch::S390x => {}
                 InlineAsmArch::SpirV => {}
-                InlineAsmArch::Wasm32 => {}
+                InlineAsmArch::Wasm32 | InlineAsmArch::Wasm64 => {}
                 InlineAsmArch::Bpf => {}
             }
         }

compiler/rustc_codegen_llvm/src/builder.rs

@@ -769,7 +769,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         // we like. To ensure that LLVM picks the right instruction we choose
         // the raw wasm intrinsic functions which avoid LLVM inserting all the
         // other control flow automatically.
-        if self.sess().target.arch == "wasm32" {
+        if self.sess().target.is_like_wasm {
             let src_ty = self.cx.val_ty(val);
             if self.cx.type_kind(src_ty) != TypeKind::Vector {
                 let float_width = self.cx.float_width(src_ty);
@@ -791,7 +791,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
 
     fn fptosi(&mut self, val: &'ll Value, dest_ty: &'ll Type) -> &'ll Value {
         // see `fptoui` above for why wasm is different here
-        if self.sess().target.arch == "wasm32" {
+        if self.sess().target.is_like_wasm {
             let src_ty = self.cx.val_ty(val);
             if self.cx.type_kind(src_ty) != TypeKind::Vector {
                 let float_width = self.cx.float_width(src_ty);

compiler/rustc_codegen_llvm/src/consts.rs

@@ -490,7 +490,7 @@ impl StaticMethods for CodegenCx<'ll, 'tcx> {
 
             // Wasm statics with custom link sections get special treatment as they
             // go into custom sections of the wasm executable.
-            if self.tcx.sess.opts.target_triple.triple().starts_with("wasm32") {
+            if self.tcx.sess.target.is_like_wasm {
                 if let Some(section) = attrs.link_section {
                     let section = llvm::LLVMMDStringInContext(
                         self.llcx,

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -75,7 +75,9 @@ unsafe fn configure_llvm(sess: &Session) {
         if sess.print_llvm_passes() {
             add("-debug-pass=Structure", false);
         }
-        if !sess.opts.debugging_opts.no_generate_arange_section {
+        if sess.target.generate_arange_section
+            && !sess.opts.debugging_opts.no_generate_arange_section
+        {
             add("-generate-arange-section", false);
         }