Auto merge of #86922 - joshtriplett:target-abi, r=oli-obk

target abi

Implement cfg(target_abi) (RFC 2992)

Add an `abi` field to `TargetOptions`, defaulting to "". Support using
`cfg(target_abi = "...")` for conditional compilation on that field.

Gated by `feature(cfg_target_abi)`.

Add a test for `target_abi`, and a test for the feature gate.

Add `target_abi` to tidy as a platform-specific cfg.

Update targets to use `target_abi`

All eabi targets have `target_abi = "eabi".`
All eabihf targets have `target_abi = "eabihf"`.
`armv6_unknown_freebsd` and `armv7_unknown_freebsd` have `target_abi = "eabihf"`.
All abi64 targets have `target_abi = "abi64"`.
All ilp32 targets have `target_abi = "ilp32"`.
All softfloat targets have `target_abi = "softfloat"`.
All *-uwp-windows-* targets have `target_abi = "uwp"`.
All spe targets have `target_abi = "spe"`.
All macabi targets have `target_abi = "macabi"`.
aarch64-apple-ios-sim has `target_abi = "sim"`.
`x86_64-fortanix-unknown-sgx` has `target_abi = "fortanix"`.
`x86_64-unknown-linux-gnux32` has `target_abi = "x32"`.

Add FIXME entries for targets for which existing values need to change
once `cfg_target_abi` becomes stable. (All of them are tier 3 targets.)

Add a test for `target_abi` in `--print cfg`.

Author: bors

compiler/rustc_feature/src/active.rs

@@ -684,6 +684,9 @@ declare_features! (
     /// Allows qualified paths in struct expressions, struct patterns and tuple struct patterns.
     (active, more_qualified_paths, "1.54.0", Some(86935), None),
 
+    /// Allows `cfg(target_abi = "...")`.
+    (active, cfg_target_abi, "1.55.0", Some(80970), None),
+
     // -------------------------------------------------------------------------
     // feature-group-end: actual feature gates
     // -------------------------------------------------------------------------

compiler/rustc_feature/src/builtin_attrs.rs

@@ -23,6 +23,7 @@ pub type GatedCfg = (Symbol, Symbol, GateFn);
 /// `cfg(...)`'s that are feature gated.
 const GATED_CFGS: &[GatedCfg] = &[
     // (name in cfg, feature, function to check if the feature is enabled)
+    (sym::target_abi, sym::cfg_target_abi, cfg_fn!(cfg_target_abi)),
     (sym::target_thread_local, sym::cfg_target_thread_local, cfg_fn!(cfg_target_thread_local)),
     (sym::target_has_atomic, sym::cfg_target_has_atomic, cfg_fn!(cfg_target_has_atomic)),
     (sym::target_has_atomic_load_store, sym::cfg_target_has_atomic, cfg_fn!(cfg_target_has_atomic)),

compiler/rustc_session/src/config.rs

@@ -805,6 +805,7 @@ fn default_configuration(sess: &Session) -> CrateConfig {
     let wordsz = sess.target.pointer_width.to_string();
     let os = &sess.target.os;
     let env = &sess.target.env;
+    let abi = &sess.target.abi;
     let vendor = &sess.target.vendor;
     let min_atomic_width = sess.target.min_atomic_width();
     let max_atomic_width = sess.target.max_atomic_width();
@@ -814,7 +815,7 @@ fn default_configuration(sess: &Session) -> CrateConfig {
     });
 
     let mut ret = FxHashSet::default();
-    ret.reserve(6); // the minimum number of insertions
+    ret.reserve(7); // the minimum number of insertions
     // Target bindings.
     ret.insert((sym::target_os, Some(Symbol::intern(os))));
     for fam in &sess.target.families {
@@ -829,6 +830,7 @@ fn default_configuration(sess: &Session) -> CrateConfig {
     ret.insert((sym::target_endian, Some(Symbol::intern(end.as_str()))));
     ret.insert((sym::target_pointer_width, Some(Symbol::intern(&wordsz))));
     ret.insert((sym::target_env, Some(Symbol::intern(env))));
+    ret.insert((sym::target_abi, Some(Symbol::intern(abi))));
     ret.insert((sym::target_vendor, Some(Symbol::intern(vendor))));
     if sess.target.has_elf_tls {
         ret.insert((sym::target_thread_local, None));

compiler/rustc_span/src/symbol.rs

@@ -354,6 +354,7 @@ symbols! {
         cfg_eval,
         cfg_panic,
         cfg_sanitize,
+        cfg_target_abi,
         cfg_target_feature,
         cfg_target_has_atomic,
         cfg_target_thread_local,
@@ -1203,6 +1204,7 @@ symbols! {
         sync,
         sync_trait,
         t32,
+        target_abi,
         target_arch,
         target_endian,
         target_env,

compiler/rustc_target/src/spec/aarch64_be_unknown_linux_gnu_ilp32.rs

@@ -10,6 +10,11 @@ pub fn target() -> Target {
         pointer_width: 32,
         data_layout: "E-m:e-p:32:32-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),
-        options: TargetOptions { mcount: "\u{1}_mcount".to_string(), endian: Endian::Big, ..base },
+        options: TargetOptions {
+            abi: "ilp32".to_string(),
+            mcount: "\u{1}_mcount".to_string(),
+            endian: Endian::Big,
+            ..base
+        },
     }
 }

compiler/rustc_target/src/spec/aarch64_unknown_linux_gnu_ilp32.rs

@@ -7,6 +7,7 @@ pub fn target() -> Target {
         data_layout: "e-m:e-p:32:32-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),
         options: TargetOptions {
+            abi: "ilp32".to_string(),
             max_atomic_width: Some(128),
             mcount: "\u{1}_mcount".to_string(),
             ..super::linux_gnu_base::opts()

compiler/rustc_target/src/spec/aarch64_unknown_none_softfloat.rs

@@ -10,6 +10,7 @@ use super::{LinkerFlavor, LldFlavor, PanicStrategy, RelocModel, Target, TargetOp
 
 pub fn target() -> Target {
     let opts = TargetOptions {
+        abi: "softfloat".to_string(),
         linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
         linker: Some("rust-lld".to_owned()),
         features: "+strict-align,-neon,-fp-armv8".to_string(),

compiler/rustc_target/src/spec/apple_sdk_base.rs

@@ -14,6 +14,15 @@ pub enum Arch {
     Arm64_sim,
 }
 
+fn target_abi(arch: Arch) -> String {
+    match arch {
+        Armv7 | Armv7s | Arm64 | I386 | X86_64 => "",
+        X86_64_macabi | Arm64_macabi => "macabi",
+        Arm64_sim => "sim",
+    }
+    .to_string()
+}
+
 fn target_cpu(arch: Arch) -> String {
     match arch {
         Armv7 => "cortex-a8", // iOS7 is supported on iPhone 4 and higher
@@ -39,6 +48,7 @@ fn link_env_remove(arch: Arch) -> Vec<String> {
 
 pub fn opts(os: &str, arch: Arch) -> TargetOptions {
     TargetOptions {
+        abi: target_abi(arch),
         cpu: target_cpu(arch),
         dynamic_linking: false,
         executables: true,

compiler/rustc_target/src/spec/arm_linux_androideabi.rs

@@ -7,6 +7,7 @@ pub fn target() -> Target {
         data_layout: "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".to_string(),
         arch: "arm".to_string(),
         options: TargetOptions {
+            abi: "eabi".to_string(),
             // https://developer.android.com/ndk/guides/abis.html#armeabi
             features: "+strict-align,+v5te".to_string(),
             max_atomic_width: Some(32),

compiler/rustc_target/src/spec/arm_unknown_linux_gnueabi.rs

@@ -7,6 +7,7 @@ pub fn target() -> Target {
         data_layout: "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".to_string(),
         arch: "arm".to_string(),
         options: TargetOptions {
+            abi: "eabi".to_string(),
             features: "+strict-align,+v6".to_string(),
             max_atomic_width: Some(64),
             mcount: "\u{1}__gnu_mcount_nc".to_string(),