diff --git a/compiler/rustc_codegen_gcc/src/builder.rs b/compiler/rustc_codegen_gcc/src/builder.rs
index f5cda81f6ab86..3cfc308c54638 100644
--- a/compiler/rustc_codegen_gcc/src/builder.rs
+++ b/compiler/rustc_codegen_gcc/src/builder.rs
@@ -31,7 +31,7 @@ use rustc_span::Span;
use rustc_target::abi::{
self, call::FnAbi, Align, HasDataLayout, Size, TargetDataLayout, WrappingRange,
};
-use rustc_target::spec::{HasTargetSpec, Target};
+use rustc_target::spec::{HasTargetSpec, HasWasmCAbiOpt, Target, WasmCAbi};
use crate::common::{type_is_pointer, SignType, TypeReflection};
use crate::context::CodegenCx;
@@ -2349,6 +2349,12 @@ impl<'tcx> HasTargetSpec for Builder<'_, '_, 'tcx> {
}
}
+impl<'tcx> HasWasmCAbiOpt for Builder<'_, '_, 'tcx> {
+ fn wasm_c_abi_opt(&self) -> WasmCAbi {
+ self.cx.wasm_c_abi_opt()
+ }
+}
+
pub trait ToGccComp {
fn to_gcc_comparison(&self) -> ComparisonOp;
}
diff --git a/compiler/rustc_codegen_gcc/src/context.rs b/compiler/rustc_codegen_gcc/src/context.rs
index bc3d62f2679d9..99c079f40e03b 100644
--- a/compiler/rustc_codegen_gcc/src/context.rs
+++ b/compiler/rustc_codegen_gcc/src/context.rs
@@ -20,7 +20,7 @@ use rustc_span::{source_map::respan, Span};
use rustc_target::abi::{
call::FnAbi, HasDataLayout, PointeeInfo, Size, TargetDataLayout, VariantIdx,
};
-use rustc_target::spec::{HasTargetSpec, Target, TlsModel};
+use rustc_target::spec::{HasTargetSpec, HasWasmCAbiOpt, Target, TlsModel, WasmCAbi};
use crate::callee::get_fn;
use crate::common::SignType;
@@ -555,6 +555,12 @@ impl<'gcc, 'tcx> HasTargetSpec for CodegenCx<'gcc, 'tcx> {
}
}
+impl<'gcc, 'tcx> HasWasmCAbiOpt for CodegenCx<'gcc, 'tcx> {
+ fn wasm_c_abi_opt(&self) -> WasmCAbi {
+ self.tcx.sess.opts.unstable_opts.wasm_c_abi
+ }
+}
+
impl<'gcc, 'tcx> LayoutOfHelpers<'tcx> for CodegenCx<'gcc, 'tcx> {
type LayoutOfResult = TyAndLayout<'tcx>;
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 4f15d1c1d3a0b..758118cb38beb 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -17,7 +17,9 @@ use rustc_session::{build_session, getopts, CompilerIO, EarlyDiagCtxt, Session};
use rustc_span::edition::{Edition, DEFAULT_EDITION};
use rustc_span::symbol::sym;
use rustc_span::{FileName, SourceFileHashAlgorithm};
-use rustc_target::spec::{CodeModel, LinkerFlavorCli, MergeFunctions, PanicStrategy, RelocModel};
+use rustc_target::spec::{
+ CodeModel, LinkerFlavorCli, MergeFunctions, PanicStrategy, RelocModel, WasmCAbi,
+};
use rustc_target::spec::{RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TlsModel};
use std::collections::{BTreeMap, BTreeSet};
use std::num::NonZero;
@@ -836,6 +838,7 @@ fn test_unstable_options_tracking_hash() {
tracked!(verify_llvm_ir, true);
tracked!(virtual_function_elimination, true);
tracked!(wasi_exec_model, Some(WasiExecModel::Reactor));
+ tracked!(wasm_c_abi, WasmCAbi::Spec);
// tidy-alphabetical-end
macro_rules! tracked_no_crate_hash {
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index b1bfd2f1105a8..e7ef7e381c2f8 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -15,7 +15,9 @@ use rustc_span::symbol::{sym, Symbol};
use rustc_span::{ErrorGuaranteed, Span, DUMMY_SP};
use rustc_target::abi::call::FnAbi;
use rustc_target::abi::*;
-use rustc_target::spec::{abi::Abi as SpecAbi, HasTargetSpec, PanicStrategy, Target};
+use rustc_target::spec::{
+ abi::Abi as SpecAbi, HasTargetSpec, HasWasmCAbiOpt, PanicStrategy, Target, WasmCAbi,
+};
use std::borrow::Cow;
use std::cmp;
@@ -539,6 +541,12 @@ impl<'tcx> HasTargetSpec for TyCtxt<'tcx> {
}
}
+impl<'tcx> HasWasmCAbiOpt for TyCtxt<'tcx> {
+ fn wasm_c_abi_opt(&self) -> WasmCAbi {
+ self.sess.opts.unstable_opts.wasm_c_abi
+ }
+}
+
impl<'tcx> HasTyCtxt<'tcx> for TyCtxt<'tcx> {
#[inline]
fn tcx(&self) -> TyCtxt<'tcx> {
@@ -584,6 +592,12 @@ impl<'tcx, T: HasTargetSpec> HasTargetSpec for LayoutCx<'tcx, T> {
}
}
+impl<'tcx, T: HasWasmCAbiOpt> HasWasmCAbiOpt for LayoutCx<'tcx, T> {
+ fn wasm_c_abi_opt(&self) -> WasmCAbi {
+ self.tcx.wasm_c_abi_opt()
+ }
+}
+
impl<'tcx, T: HasTyCtxt<'tcx>> HasTyCtxt<'tcx> for LayoutCx<'tcx, T> {
fn tcx(&self) -> TyCtxt<'tcx> {
self.tcx.tcx()
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 61a220428b03b..2213a626d4fef 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -3227,7 +3227,7 @@ pub(crate) mod dep_tracking {
use rustc_feature::UnstableFeatures;
use rustc_span::edition::Edition;
use rustc_span::RealFileName;
- use rustc_target::spec::{CodeModel, MergeFunctions, PanicStrategy, RelocModel};
+ use rustc_target::spec::{CodeModel, MergeFunctions, PanicStrategy, RelocModel, WasmCAbi};
use rustc_target::spec::{
RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TargetTriple, TlsModel,
};
@@ -3324,6 +3324,7 @@ pub(crate) mod dep_tracking {
Polonius,
InliningThreshold,
FunctionReturn,
+ WasmCAbi,
);
impl<T1, T2> DepTrackingHash for (T1, T2)
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 93bef82e4ba15..75f3130a8bd57 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -8,7 +8,9 @@ use rustc_data_structures::profiling::TimePassesFormat;
use rustc_data_structures::stable_hasher::Hash64;
use rustc_errors::ColorConfig;
use rustc_errors::{LanguageIdentifier, TerminalUrl};
-use rustc_target::spec::{CodeModel, LinkerFlavorCli, MergeFunctions, PanicStrategy, SanitizerSet};
+use rustc_target::spec::{
+ CodeModel, LinkerFlavorCli, MergeFunctions, PanicStrategy, SanitizerSet, WasmCAbi,
+};
use rustc_target::spec::{
RelocModel, RelroLevel, SplitDebuginfo, StackProtector, TargetTriple, TlsModel,
};
@@ -437,6 +439,7 @@ mod desc {
"either a boolean (`yes`, `no`, `on`, `off`, etc), or a non-negative number";
pub const parse_llvm_module_flag: &str = "<key>:<type>:<value>:<behavior>. Type must currently be `u32`. Behavior should be one of (`error`, `warning`, `require`, `override`, `append`, `appendunique`, `max`, `min`)";
pub const parse_function_return: &str = "`keep` or `thunk-extern`";
+ pub const parse_wasm_c_abi: &str = "`legacy` or `spec`";
}
mod parse {
@@ -1402,6 +1405,15 @@ mod parse {
}
true
}
+
+ pub(crate) fn parse_wasm_c_abi(slot: &mut WasmCAbi, v: Option<&str>) -> bool {
+ match v {
+ Some("spec") => *slot = WasmCAbi::Spec,
+ Some("legacy") => *slot = WasmCAbi::Legacy,
+ _ => return false,
+ }
+ true
+ }
}
options! {
@@ -2021,6 +2033,8 @@ written to standard error output)"),
Requires `-Clto[=[fat,yes]]`"),
wasi_exec_model: Option<WasiExecModel> = (None, parse_wasi_exec_model, [TRACKED],
"whether to build a wasi command or reactor"),
+ wasm_c_abi: WasmCAbi = (WasmCAbi::Legacy, parse_wasm_c_abi, [TRACKED],
+ "use spec-compliant C ABI for `wasm32-unknown-unknown` (default: legacy)"),
write_long_types_to_disk: bool = (true, parse_bool, [UNTRACKED],
"whether long type names should be written to files instead of being printed in errors"),
// tidy-alphabetical-end
diff --git a/compiler/rustc_target/src/abi/call/mod.rs b/compiler/rustc_target/src/abi/call/mod.rs
index f4967b94e930a..930edfe1f0df3 100644
--- a/compiler/rustc_target/src/abi/call/mod.rs
+++ b/compiler/rustc_target/src/abi/call/mod.rs
@@ -1,6 +1,6 @@
use crate::abi::{self, Abi, Align, FieldsShape, Size};
use crate::abi::{HasDataLayout, TyAbiInterface, TyAndLayout};
-use crate::spec::{self, HasTargetSpec};
+use crate::spec::{self, HasTargetSpec, HasWasmCAbiOpt};
use rustc_span::Symbol;
use std::fmt;
use std::str::FromStr;
@@ -782,7 +782,7 @@ impl<'a, Ty> FnAbi<'a, Ty> {
) -> Result<(), AdjustForForeignAbiError>
where
Ty: TyAbiInterface<'a, C> + Copy,
- C: HasDataLayout + HasTargetSpec,
+ C: HasDataLayout + HasTargetSpec + HasWasmCAbiOpt,
{
if abi == spec::abi::Abi::X86Interrupt {
if let Some(arg) = self.args.first_mut() {
@@ -839,7 +839,9 @@ impl<'a, Ty> FnAbi<'a, Ty> {
"sparc" => sparc::compute_abi_info(cx, self),
"sparc64" => sparc64::compute_abi_info(cx, self),
"nvptx64" => {
- if cx.target_spec().adjust_abi(abi, self.c_variadic) == spec::abi::Abi::PtxKernel {
+ if cx.target_spec().adjust_abi(cx, abi, self.c_variadic)
+ == spec::abi::Abi::PtxKernel
+ {
nvptx64::compute_ptx_kernel_abi_info(cx, self)
} else {
nvptx64::compute_abi_info(self)
@@ -848,7 +850,7 @@ impl<'a, Ty> FnAbi<'a, Ty> {
"hexagon" => hexagon::compute_abi_info(self),
"riscv32" | "riscv64" => riscv::compute_abi_info(cx, self),
"wasm32" | "wasm64" => {
- if cx.target_spec().adjust_abi(abi, self.c_variadic) == spec::abi::Abi::Wasm {
+ if cx.target_spec().adjust_abi(cx, abi, self.c_variadic) == spec::abi::Abi::Wasm {
wasm::compute_wasm_abi_info(self)
} else {
wasm::compute_c_abi_info(cx, self)
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 3b6e15fad4661..578faf3f93534 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -37,7 +37,7 @@
use crate::abi::call::Conv;
use crate::abi::{Endian, Integer, Size, TargetDataLayout, TargetDataLayoutErrors};
use crate::json::{Json, ToJson};
-use crate::spec::abi::{lookup as lookup_abi, Abi};
+use crate::spec::abi::Abi;
use crate::spec::crt_objects::CrtObjects;
use rustc_fs_util::try_canonicalize;
use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
@@ -1807,6 +1807,19 @@ impl HasTargetSpec for Target {
}
}
+/// Which C ABI to use for `wasm32-unknown-unknown`.
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+pub enum WasmCAbi {
+ /// Spec-compliant C ABI.
+ Spec,
+ /// Legacy ABI. Which is non-spec-compliant.
+ Legacy,
+}
+
+pub trait HasWasmCAbiOpt {
+ fn wasm_c_abi_opt(&self) -> WasmCAbi;
+}
+
type StaticCow<T> = Cow<'static, T>;
/// Optional aspects of a target specification.
@@ -2154,9 +2167,6 @@ pub struct TargetOptions {
/// distributed with the target, the sanitizer should still appear in this list for the target.
pub supported_sanitizers: SanitizerSet,
- /// If present it's a default value to use for adjusting the C ABI.
- pub default_adjusted_cabi: Option<Abi>,
-
/// Minimum number of bits in #[repr(C)] enum. Defaults to the size of c_int
pub c_enum_min_bits: Option<u64>,
@@ -2386,7 +2396,6 @@ impl Default for TargetOptions {
// `Off` is supported by default, but targets can remove this manually, e.g. Windows.
supported_split_debuginfo: Cow::Borrowed(&[SplitDebuginfo::Off]),
supported_sanitizers: SanitizerSet::empty(),
- default_adjusted_cabi: None,
c_enum_min_bits: None,
generate_arange_section: true,
supports_stack_protector: true,
@@ -2417,9 +2426,21 @@ impl DerefMut for Target {
impl Target {
/// Given a function ABI, turn it into the correct ABI for this target.
- pub fn adjust_abi(&self, abi: Abi, c_variadic: bool) -> Abi {
+ pub fn adjust_abi<C>(&self, cx: &C, abi: Abi, c_variadic: bool) -> Abi
+ where
+ C: HasWasmCAbiOpt,
+ {
match abi {
- Abi::C { .. } => self.default_adjusted_cabi.unwrap_or(abi),
+ Abi::C { .. } => {
+ if self.arch == "wasm32"
+ && self.os == "unknown"
+ && cx.wasm_c_abi_opt() == WasmCAbi::Legacy
+ {
+ Abi::Wasm
+ } else {
+ abi
+ }
+ }
// On Windows, `extern "system"` behaves like msvc's `__stdcall`.
// `__stdcall` only applies on x86 and on non-variadic functions:
@@ -2942,16 +2963,6 @@ impl Target {
}
}
} );
- ($key_name:ident, Option<Abi>) => ( {
- let name = (stringify!($key_name)).replace("_", "-");
- obj.remove(&name).and_then(|o| o.as_str().and_then(|s| {
- match lookup_abi(s) {
- Ok(abi) => base.$key_name = Some(abi),
- _ => return Some(Err(format!("'{}' is not a valid value for abi", s))),
- }
- Some(Ok(()))
- })).unwrap_or(Ok(()))
- } );
($key_name:ident, TargetFamilies) => ( {
if let Some(value) = obj.remove("target-family") {
if let Some(v) = value.as_array() {
@@ -3101,7 +3112,6 @@ impl Target {
key!(split_debuginfo, SplitDebuginfo)?;
key!(supported_split_debuginfo, fallible_list)?;
key!(supported_sanitizers, SanitizerSet)?;
- key!(default_adjusted_cabi, Option<Abi>)?;
key!(generate_arange_section, bool);
key!(supports_stack_protector, bool);
key!(entry_name);
@@ -3365,10 +3375,6 @@ impl ToJson for Target {
target_option_val!(entry_abi);
target_option_val!(supports_xray);
- if let Some(abi) = self.default_adjusted_cabi {
- d.insert("default-adjusted-cabi".into(), Abi::name(abi).to_json());
- }
-
// Serializing `-Clink-self-contained` needs a dynamic key to support the
// backwards-compatible variants.
d.insert(self.link_self_contained.json_key().into(), self.link_self_contained.to_json());
diff --git a/compiler/rustc_target/src/spec/targets/wasm32_unknown_unknown.rs b/compiler/rustc_target/src/spec/targets/wasm32_unknown_unknown.rs
index 94ded57d2f0cd..7db4d8aca5628 100644
--- a/compiler/rustc_target/src/spec/targets/wasm32_unknown_unknown.rs
+++ b/compiler/rustc_target/src/spec/targets/wasm32_unknown_unknown.rs
@@ -10,23 +10,12 @@
//! This target is more or less managed by the Rust and WebAssembly Working
//! Group nowadays at <https://github.com/rustwasm>.
-use crate::spec::abi::Abi;
use crate::spec::{base, Cc, LinkerFlavor, Target};
pub fn target() -> Target {
let mut options = base::wasm::options();
options.os = "unknown".into();
- // This is a default for backwards-compatibility with the original
- // definition of this target oh-so-long-ago. Once the "wasm" ABI is
- // stable and the wasm-bindgen project has switched to using it then there's
- // no need for this and it can be removed.
- //
- // Currently this is the reason that this target's ABI is mismatched with
- // clang's ABI. This means that, in the limit, you can't merge C and Rust
- // code on this target due to this ABI mismatch.
- options.default_adjusted_cabi = Some(Abi::Wasm);
-
options.add_pre_link_args(
LinkerFlavor::WasmLld(Cc::No),
&[
diff --git a/compiler/rustc_ty_utils/src/abi.rs b/compiler/rustc_ty_utils/src/abi.rs
index a5328baadb5fc..71bcf898ceab2 100644
--- a/compiler/rustc_ty_utils/src/abi.rs
+++ b/compiler/rustc_ty_utils/src/abi.rs
@@ -311,7 +311,7 @@ fn fn_sig_for_fn_abi<'tcx>(
#[inline]
fn conv_from_spec_abi(tcx: TyCtxt<'_>, abi: SpecAbi, c_variadic: bool) -> Conv {
use rustc_target::spec::abi::Abi::*;
- match tcx.sess.target.adjust_abi(abi, c_variadic) {
+ match tcx.sess.target.adjust_abi(&tcx, abi, c_variadic) {
RustIntrinsic | Rust | RustCall => Conv::Rust,
// This is intentionally not using `Conv::Cold`, as that has to preserve
diff --git a/src/doc/unstable-book/src/compiler-flags/wasm-c-abi.md b/src/doc/unstable-book/src/compiler-flags/wasm-c-abi.md
new file mode 100644
index 0000000000000..138a98dbe3dcd
--- /dev/null
+++ b/src/doc/unstable-book/src/compiler-flags/wasm-c-abi.md
@@ -0,0 +1,10 @@
+# `wasm-c-abi`
+
+This option controls whether Rust uses the spec-compliant C ABI when compiling
+for the `wasm32-unknown-unknown` target.
+
+This makes it possible to be ABI-compatible with all other spec-compliant Wasm
+like Rusts `wasm32-wasi`.
+
+This compiler flag is perma-unstable, as it will be enabled by default in the
+future with no option to fall back to the old non-spec-compliant ABI.