Rollup merge of rust-lang#153857 - RalfJung:cfg-abi, r=Mark-Simulacrum

Rename `target.abi` to `target.cfg_abi` and enum-ify llvm_abiname

See [Zulip](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/De-spaghettifying.20ABI.20controls/with/578893542) for more context. Discussed a bit in rust-lang#153769 (comment) too.

This renames `target.abi` to `target.cfg_abi` to make it less likely that someone will use it to determine things about the actual ccABI, i.e. the calling convention used on the target. `target.abi` does not control that calling convention, it just *sometimes* informs the user about that calling convention (and also about other aspects of the ABI).

Also turn llvm_abiname into an enum to make it more natural to match on.
Cc @workingjubilee @madsmtm

Author: JonathanBrouwer

compiler/rustc_codegen_cranelift/src/lib.rs

@@ -46,7 +46,7 @@ use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_session::Session;
 use rustc_session::config::OutputFilenames;
 use rustc_span::{Symbol, sym};
-use rustc_target::spec::{Abi, Arch, Env, Os};
+use rustc_target::spec::{Arch, CfgAbi, Env, Os};
 
 pub use crate::config::*;
 use crate::prelude::*;
@@ -178,7 +178,7 @@ impl CodegenBackend for CraneliftCodegenBackend {
         let has_reliable_f16_f128 = !(sess.target.arch == Arch::X86_64
             && sess.target.os == Os::Windows
             && sess.target.env == Env::Gnu
-            && sess.target.abi != Abi::Llvm);
+            && sess.target.cfg_abi != CfgAbi::Llvm);
 
         // FIXME(f128): f128 math operations need f128 math symbols, which currently aren't always
         // filled in by compiler-builtins. The only libc that provides these currently is glibc.

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -225,7 +225,7 @@ pub(crate) fn target_machine_factory(
     let triple = SmallCStr::new(&versioned_llvm_target(sess));
     let cpu = SmallCStr::new(llvm_util::target_cpu(sess));
     let features = CString::new(target_features.join(",")).unwrap();
-    let abi = SmallCStr::new(&sess.target.llvm_abiname);
+    let abi = SmallCStr::new(sess.target.llvm_abiname.desc());
     let trap_unreachable =
         sess.opts.unstable_opts.trap_unreachable.unwrap_or(sess.target.trap_unreachable);
     let emit_stack_size_section = sess.opts.unstable_opts.emit_stack_sizes;

compiler/rustc_codegen_llvm/src/context.rs

@@ -28,7 +28,7 @@ use rustc_session::config::{
 use rustc_span::{DUMMY_SP, Span, Spanned, Symbol};
 use rustc_symbol_mangling::mangle_internal_symbol;
 use rustc_target::spec::{
-    Abi, Arch, Env, HasTargetSpec, Os, RelocModel, SmallDataThresholdSupport, Target, TlsModel,
+    Arch, CfgAbi, Env, HasTargetSpec, Os, RelocModel, SmallDataThresholdSupport, Target, TlsModel,
 };
 use smallvec::SmallVec;
 
@@ -344,7 +344,7 @@ pub(crate) unsafe fn create_module<'ll>(
     if sess.target.is_like_msvc
         || (sess.target.options.os == Os::Windows
             && sess.target.options.env == Env::Gnu
-            && sess.target.options.abi == Abi::Llvm)
+            && sess.target.options.cfg_abi == CfgAbi::Llvm)
     {
         match sess.opts.cg.control_flow_guard {
             CFGuard::Disabled => {}
@@ -509,14 +509,13 @@ pub(crate) unsafe fn create_module<'ll>(
     // to workaround lld as the LTO plugin not
     // correctly setting target-abi for the LTO object
     // FIXME: https://github.com/llvm/llvm-project/issues/50591
-    // If llvm_abiname is empty, emit nothing.
     let llvm_abiname = &sess.target.options.llvm_abiname;
-    if matches!(sess.target.arch, Arch::RiscV32 | Arch::RiscV64) && !llvm_abiname.is_empty() {
+    if matches!(sess.target.arch, Arch::RiscV32 | Arch::RiscV64) {
         llvm::add_module_flag_str(
             llmod,
             llvm::ModuleFlagMergeBehavior::Error,
             "target-abi",
-            llvm_abiname,
+            llvm_abiname.desc(),
         );
     }
 

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -16,7 +16,7 @@ use rustc_middle::bug;
 use rustc_session::Session;
 use rustc_session::config::{PrintKind, PrintRequest};
 use rustc_target::spec::{
-    Abi, Arch, Env, MergeFunctions, Os, PanicStrategy, SmallDataThresholdSupport,
+    Arch, CfgAbi, Env, MergeFunctions, Os, PanicStrategy, SmallDataThresholdSupport,
 };
 use smallvec::{SmallVec, smallvec};
 
@@ -362,7 +362,7 @@ fn update_target_reliable_float_cfg(sess: &Session, cfg: &mut TargetConfig) {
     let target_arch = &sess.target.arch;
     let target_os = &sess.target.options.os;
     let target_env = &sess.target.options.env;
-    let target_abi = &sess.target.options.abi;
+    let target_abi = &sess.target.options.cfg_abi;
     let target_pointer_width = sess.target.pointer_width;
     let version = get_version();
     let (major, _, _) = version;
@@ -371,7 +371,9 @@ fn update_target_reliable_float_cfg(sess: &Session, cfg: &mut TargetConfig) {
         // Unsupported <https://github.com/llvm/llvm-project/issues/94434> (fixed in llvm22)
         (Arch::Arm64EC, _) if major < 22 => false,
         // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
-        (Arch::X86_64, Os::Windows) if *target_env == Env::Gnu && *target_abi != Abi::Llvm => false,
+        (Arch::X86_64, Os::Windows) if *target_env == Env::Gnu && *target_abi != CfgAbi::Llvm => {
+            false
+        }
         // Infinite recursion <https://github.com/llvm/llvm-project/issues/97981>
         (Arch::CSky, _) if major < 22 => false, // (fixed in llvm22)
         (Arch::PowerPC | Arch::PowerPC64, _) if major < 22 => false, // (fixed in llvm22)
@@ -397,7 +399,9 @@ fn update_target_reliable_float_cfg(sess: &Session, cfg: &mut TargetConfig) {
         // ABI unsupported  <https://github.com/llvm/llvm-project/issues/41838> (fixed in llvm22)
         (Arch::Sparc, _) if major < 22 => false,
         // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
-        (Arch::X86_64, Os::Windows) if *target_env == Env::Gnu && *target_abi != Abi::Llvm => false,
+        (Arch::X86_64, Os::Windows) if *target_env == Env::Gnu && *target_abi != CfgAbi::Llvm => {
+            false
+        }
         // There are no known problems on other platforms, so the only requirement is that symbols
         // are available. `compiler-builtins` provides all symbols required for core `f128`
         // support, so this should work for everything else.

compiler/rustc_codegen_llvm/src/va_arg.rs

@@ -8,7 +8,7 @@ use rustc_codegen_ssa::traits::{
 use rustc_middle::bug;
 use rustc_middle::ty::Ty;
 use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, TyAndLayout};
-use rustc_target::spec::{Arch, Env, RustcAbi};
+use rustc_target::spec::{Arch, Env, LlvmAbi, RustcAbi};
 
 use crate::builder::Builder;
 use crate::llvm::{Type, Value};
@@ -1077,7 +1077,7 @@ pub(super) fn emit_va_arg<'ll, 'tcx>(
             AllowHigherAlign::Yes,
             ForceRightAdjust::Yes,
         ),
-        Arch::RiscV32 if target.llvm_abiname == "ilp32e" => {
+        Arch::RiscV32 if target.llvm_abiname == LlvmAbi::Ilp32e => {
             // FIXME: clang manually adjusts the alignment for this ABI. It notes:
             //
             // > To be compatible with GCC's behaviors, we force arguments with

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -47,7 +47,7 @@ use rustc_session::{Session, filesearch};
 use rustc_span::Symbol;
 use rustc_target::spec::crt_objects::CrtObjects;
 use rustc_target::spec::{
-    Abi, BinaryFormat, Cc, Env, LinkOutputKind, LinkSelfContainedComponents,
+    BinaryFormat, Cc, CfgAbi, Env, LinkOutputKind, LinkSelfContainedComponents,
     LinkSelfContainedDefault, LinkerFeatures, LinkerFlavor, LinkerFlavorCli, Lld, Os, RelocModel,
     RelroLevel, SanitizerSet, SplitDebuginfo,
 };
@@ -1917,7 +1917,7 @@ fn self_contained_components(
                 LinkSelfContainedDefault::InferredForMusl => sess.crt_static(Some(crate_type)),
                 LinkSelfContainedDefault::InferredForMingw => {
                     sess.host == sess.target
-                        && sess.target.abi != Abi::Uwp
+                        && sess.target.cfg_abi != CfgAbi::Uwp
                         && detect_self_contained_mingw(sess, linker)
                 }
             }

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -18,7 +18,7 @@ use rustc_middle::middle::exported_symbols::{
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::config::{self, CrateType, DebugInfo, LinkerPluginLto, Lto, OptLevel, Strip};
-use rustc_target::spec::{Abi, Arch, Cc, LinkOutputKind, LinkerFlavor, Lld, Os};
+use rustc_target::spec::{Arch, Cc, CfgAbi, LinkOutputKind, LinkerFlavor, Lld, Os};
 use tracing::{debug, warn};
 
 use super::command::Command;
@@ -84,7 +84,7 @@ pub(crate) fn get_linker<'a>(
     // To comply with the Windows App Certification Kit,
     // MSVC needs to link with the Store versions of the runtime libraries (vcruntime, msvcrt, etc).
     let t = &sess.target;
-    if matches!(flavor, LinkerFlavor::Msvc(..)) && t.abi == Abi::Uwp {
+    if matches!(flavor, LinkerFlavor::Msvc(..)) && t.cfg_abi == CfgAbi::Uwp {
         if let Some(ref tool) = msvc_tool {
             let original_path = tool.path();
             if let Some(root_lib_path) = original_path.ancestors().nth(4) {
@@ -135,7 +135,7 @@ pub(crate) fn get_linker<'a>(
 
     // FIXME: Move `/LIBPATH` addition for uwp targets from the linker construction
     // to the linker args construction.
-    assert!(cmd.get_args().is_empty() || sess.target.abi == Abi::Uwp);
+    assert!(cmd.get_args().is_empty() || sess.target.cfg_abi == CfgAbi::Uwp);
     match flavor {
         LinkerFlavor::Unix(Cc::No) if sess.target.os == Os::L4Re => {
             Box::new(L4Bender::new(cmd, sess)) as Box<dyn Linker>

compiler/rustc_codegen_ssa/src/back/metadata.rs

@@ -20,7 +20,7 @@ use rustc_metadata::fs::METADATA_FILENAME;
 use rustc_middle::bug;
 use rustc_session::Session;
 use rustc_span::sym;
-use rustc_target::spec::{Abi, Os, RelocModel, Target, ef_avr_arch};
+use rustc_target::spec::{CfgAbi, LlvmAbi, Os, RelocModel, Target, ef_avr_arch};
 use tracing::debug;
 
 use super::apple;
@@ -295,10 +295,10 @@ pub(super) fn elf_e_flags(architecture: Architecture, sess: &Session) -> u32 {
             };
 
             // Use the explicitly given ABI.
-            match sess.target.options.llvm_abiname.as_ref() {
-                "o32" if is_32bit => e_flags |= elf::EF_MIPS_ABI_O32,
-                "n32" if !is_32bit => e_flags |= elf::EF_MIPS_ABI2,
-                "n64" if !is_32bit => {}
+            match &sess.target.options.llvm_abiname {
+                LlvmAbi::O32 if is_32bit => e_flags |= elf::EF_MIPS_ABI_O32,
+                LlvmAbi::N32 if !is_32bit => e_flags |= elf::EF_MIPS_ABI2,
+                LlvmAbi::N64 if !is_32bit => {}
                 // The rest is invalid (which is already ensured by the target spec check).
                 s => bug!("invalid LLVM ABI `{}` for MIPS target", s),
             };
@@ -336,12 +336,12 @@ pub(super) fn elf_e_flags(architecture: Architecture, sess: &Session) -> u32 {
 
             // Set the appropriate flag based on ABI
             // This needs to match LLVM `RISCVELFStreamer.cpp`
-            match &*sess.target.llvm_abiname {
-                "ilp32" | "lp64" => (),
-                "ilp32f" | "lp64f" => e_flags |= elf::EF_RISCV_FLOAT_ABI_SINGLE,
-                "ilp32d" | "lp64d" => e_flags |= elf::EF_RISCV_FLOAT_ABI_DOUBLE,
+            match &sess.target.llvm_abiname {
+                LlvmAbi::Ilp32 | LlvmAbi::Lp64 => (),
+                LlvmAbi::Ilp32f | LlvmAbi::Lp64f => e_flags |= elf::EF_RISCV_FLOAT_ABI_SINGLE,
+                LlvmAbi::Ilp32d | LlvmAbi::Lp64d => e_flags |= elf::EF_RISCV_FLOAT_ABI_DOUBLE,
                 // Note that the `lp64e` is still unstable as it's not (yet) part of the ELF psABI.
-                "ilp32e" | "lp64e" => e_flags |= elf::EF_RISCV_RVE,
+                LlvmAbi::Ilp32e | LlvmAbi::Lp64e => e_flags |= elf::EF_RISCV_RVE,
                 _ => bug!("unknown RISC-V ABI name"),
             }
 
@@ -353,10 +353,10 @@ pub(super) fn elf_e_flags(architecture: Architecture, sess: &Session) -> u32 {
 
             // Set the appropriate flag based on ABI
             // This needs to match LLVM `LoongArchELFStreamer.cpp`
-            match &*sess.target.llvm_abiname {
-                "ilp32s" | "lp64s" => e_flags |= elf::EF_LARCH_ABI_SOFT_FLOAT,
-                "ilp32f" | "lp64f" => e_flags |= elf::EF_LARCH_ABI_SINGLE_FLOAT,
-                "ilp32d" | "lp64d" => e_flags |= elf::EF_LARCH_ABI_DOUBLE_FLOAT,
+            match &sess.target.llvm_abiname {
+                LlvmAbi::Ilp32s | LlvmAbi::Lp64s => e_flags |= elf::EF_LARCH_ABI_SOFT_FLOAT,
+                LlvmAbi::Ilp32f | LlvmAbi::Lp64f => e_flags |= elf::EF_LARCH_ABI_SINGLE_FLOAT,
+                LlvmAbi::Ilp32d | LlvmAbi::Lp64d => e_flags |= elf::EF_LARCH_ABI_DOUBLE_FLOAT,
                 _ => bug!("unknown LoongArch ABI name"),
             }
 
@@ -372,7 +372,7 @@ pub(super) fn elf_e_flags(architecture: Architecture, sess: &Session) -> u32 {
             }
         }
         Architecture::Csky => {
-            if matches!(sess.target.options.abi, Abi::AbiV2) {
+            if matches!(sess.target.options.cfg_abi, CfgAbi::AbiV2) {
                 elf::EF_CSKY_ABIV2
             } else {
                 elf::EF_CSKY_ABIV1
@@ -383,14 +383,14 @@ pub(super) fn elf_e_flags(architecture: Architecture, sess: &Session) -> u32 {
             const EF_PPC64_ABI_ELF_V1: u32 = 1;
             const EF_PPC64_ABI_ELF_V2: u32 = 2;
 
-            match sess.target.options.llvm_abiname.as_ref() {
+            match sess.target.options.llvm_abiname {
                 // If the flags do not correctly indicate the ABI,
                 // linkers such as ld.lld assume that the ppc64 object files are always ELFv2
                 // which leads to broken binaries if ELFv1 is used for the object files.
-                "elfv1" => EF_PPC64_ABI_ELF_V1,
-                "elfv2" => EF_PPC64_ABI_ELF_V2,
-                "" if sess.target.options.binary_format.to_object() == BinaryFormat::Elf => {
-                    bug!("No ABI specified for this PPC64 ELF target");
+                LlvmAbi::ElfV1 => EF_PPC64_ABI_ELF_V1,
+                LlvmAbi::ElfV2 => EF_PPC64_ABI_ELF_V2,
+                _ if sess.target.options.binary_format.to_object() == BinaryFormat::Elf => {
+                    bug!("invalid ABI specified for this PPC64 ELF target");
                 }
                 // Fall back
                 _ => EF_PPC64_ABI_UNKNOWN,

compiler/rustc_codegen_ssa/src/common.rs

@@ -7,7 +7,7 @@ use rustc_middle::ty::{self, Instance, TyCtxt};
 use rustc_middle::{bug, mir, span_bug};
 use rustc_session::cstore::{DllCallingConvention, DllImport, DllImportSymbolType};
 use rustc_span::Span;
-use rustc_target::spec::{Abi, Env, Os, Target};
+use rustc_target::spec::{CfgAbi, Env, Os, Target};
 
 use crate::traits::*;
 
@@ -171,7 +171,7 @@ pub fn asm_const_to_str<'tcx>(
 }
 
 pub fn is_mingw_gnu_toolchain(target: &Target) -> bool {
-    target.os == Os::Windows && target.env == Env::Gnu && target.abi == Abi::Unspecified
+    target.os == Os::Windows && target.env == Env::Gnu && target.cfg_abi == CfgAbi::Unspecified
 }
 
 pub fn i686_decorated_name(

compiler/rustc_metadata/src/native_libs.rs

@@ -19,7 +19,7 @@ use rustc_session::cstore::{
 use rustc_session::search_paths::PathKind;
 use rustc_span::Symbol;
 use rustc_span::def_id::{DefId, LOCAL_CRATE};
-use rustc_target::spec::{Abi, Arch, BinaryFormat, Env, LinkSelfContainedComponents, Os};
+use rustc_target::spec::{Arch, BinaryFormat, CfgAbi, Env, LinkSelfContainedComponents, Os};
 
 use crate::errors;
 
@@ -73,14 +73,14 @@ pub fn walk_native_lib_search_dirs<R>(
     // FIXME: On AIX this also has the side-effect of making the list of library search paths
     // non-empty, which is needed or the linker may decide to record the LIBPATH env, if
     // defined, as the search path instead of appending the default search paths.
-    if sess.target.abi == Abi::Fortanix
+    if sess.target.cfg_abi == CfgAbi::Fortanix
         || sess.target.os == Os::Linux
         || sess.target.os == Os::Fuchsia
         || sess.target.is_like_aix
         || sess.target.is_like_darwin && !sess.sanitizers().is_empty()
         || sess.target.os == Os::Windows
             && sess.target.env == Env::Gnu
-            && sess.target.abi == Abi::Llvm
+            && sess.target.cfg_abi == CfgAbi::Llvm
     {
         f(&sess.target_tlib_path.dir, false)?;
     }