【问题标题】：How to solve "#error Unsupported architecture" when building Rust code with wasm-pack?使用 wasm-pack 构建 Rust 代码时如何解决“#error Unsupported architecture”？
【发布时间】：2019-09-11 12:19:43
【问题描述】：

我正在尝试通过构建一个演示应用程序来操作一些存档文件来学习 Rust 和 WebAssembly。

添加“zip”包后，我能够成功运行cargo build，但不能成功运行wasm-pack build（也不是cargo build --target wasm32-unknown-unknown）。

我在尝试构建我的文件时收到 cargo:warning=#error Unsupported architecture，而 clang 似乎对它不满意。

起初我得到一些stdio.h not found，所以我跑了

open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg

安装它们。

我现在遇到以下错误：

   Compiling bzip2-sys v0.1.7
error: failed to run custom build command for `bzip2-sys v0.1.7`
process didn't exit successfully: `/Users/projects/rust/hello-wasm/target/release/build/bzip2-sys-b7b1e1aeb1e6f42f/build-script-build` (exit code: 101)
--- stdout
TARGET = Some("wasm32-unknown-unknown")
OPT_LEVEL = Some("s")
HOST = Some("x86_64-apple-darwin")
CC_wasm32-unknown-unknown = None
CC_wasm32_unknown_unknown = None
TARGET_CC = None
CC = None
CFLAGS_wasm32-unknown-unknown = None
CFLAGS_wasm32_unknown_unknown = None
TARGET_CFLAGS = None
CFLAGS = None
CRATE_CC_NO_DEFAULTS = None
DEBUG = Some("false")
running: "clang" "-Os" "-ffunction-sections" "-fdata-sections" "-fPIC" "--target=wasm32-unknown-unknown" "-I" "bzip2-1.0.6" "-D_FILE_OFFSET_BITS=64" "-DBZ_NO_STDIO" "-o" "/Users/projects/rust/hello-wasm/target/wasm32-unknown-unknown/release/build/bzip2-sys-3be942e6fa7d3879/out/lib/bzip2-1.0.6/blocksort.o" "-c" "bzip2-1.0.6/blocksort.c"
cargo:warning=In file included from bzip2-1.0.6/blocksort.c:22:
cargo:warning=In file included from bzip2-1.0.6/bzlib_private.h:25:
cargo:warning=In file included from /usr/include/stdlib.h:62:
cargo:warning=/usr/include/sys/cdefs.h:784:2: error: Unsupported architecture
cargo:warning=#error Unsupported architecture
cargo:warning= ^
cargo:warning=In file included from bzip2-1.0.6/blocksort.c:22:
cargo:warning=In file included from bzip2-1.0.6/bzlib_private.h:25:
cargo:warning=In file included from /usr/include/stdlib.h:64:
cargo:warning=In file included from /usr/include/_types.h:27:
cargo:warning=In file included from /usr/include/sys/_types.h:33:
cargo:warning=/usr/include/machine/_types.h:34:2: error: architecture not supported
cargo:warning=#error architecture not supported
cargo:warning= ^
cargo:warning=In file included from bzip2-1.0.6/blocksort.c:22:
cargo:warning=In file included from bzip2-1.0.6/bzlib_private.h:25:
cargo:warning=In file included from /usr/include/stdlib.h:64:
cargo:warning=In file included from /usr/include/_types.h:27:
cargo:warning=/usr/include/sys/_types.h:55:9: error: unknown type name '__int64_t'; did you mean '__int128_t'?
cargo:warning=typedef __int64_t       __darwin_blkcnt_t;      /* total blocks */
cargo:warning=        ^
cargo:warning=note: '__int128_t' declared here
[...]
Internal error occurred: Command "clang" "-Os" "-ffunction-sections" "-fdata-sections" "-fPIC" "--target=wasm32-unknown-unknown" "-I" "bzip2-1.0.6" "-D_FILE_OFFSET_BITS=64" "-DBZ_NO_STDIO" "-o" "/Users/projects/rust/hello-wasm/target/wasm32-unknown-unknown/release/build/bzip2-sys-3be942e6fa7d3879/out/lib/bzip2-1.0.6/blocksort.o" "-c" "bzip2-1.0.6/blocksort.c" with args "clang" did not execute successfully (status code exit code: 1).

然后我跑了：

rustup target add wasm32-unknown-unknown --toolchain nightly
rustup default nightly

安装目标 wasm32-unknown-unknown 但我仍然收到错误。

为 wasm 编译“zip”板条箱时我缺少什么？

环境

macOS 10.14.4

gcc -v
Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 10.0.1 (clang-1001.0.46.4)
Target: x86_64-apple-darwin18.5.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

rustc --version                                             
rustc 1.36.0-nightly (31a75a172 2019-04-21)

rustup show                                                                
Default host: x86_64-apple-darwin

installed toolchains
--------------------

stable-x86_64-apple-darwin
nightly-2019-04-16-x86_64-apple-darwin
nightly-x86_64-apple-darwin (default)

installed targets for active toolchain
--------------------------------------

wasm32-unknown-unknown
x86_64-apple-darwin

active toolchain
----------------

nightly-x86_64-apple-darwin (default)
rustc 1.36.0-nightly (31a75a172 2019-04-21)

【问题讨论】：

#error Unsupported architecture 是 C 编译器错误（您可以在周围的行中看到 .c 文件）。您选择了一个实际编译 C 库以完成所有繁重的压缩工作的 crate，但该 C 库无法编译为 WASM（至少在您的配置中）。最简单的事情是找到一个纯 Rust 实现。
非常感谢。我最终从这个 crate 中禁用了 bzip 支持，因为作者在我的 Cargo.toml 中使用以下配置通过功能标志离开了这样做的可能性：zip = { version = "0.5.2", default-features = false, features = ["deflate"] }

标签： rust webassembly

【解决方案1】：

选择一个

将wasm32-unknown-unknown 替换为wasm32-unknown-emscripten
从 C 源代码中删除 #include <stdio.h>、printf 和其他标准库调用
为 wasm32-unknown-unknown 或提取和复制 emscripten 的实现实现所需的函数 (printf?)

【讨论】：