Auto merge of #77943 - est31:target_refactor, r=petrochenkov

No more target.target

Two main changes of this PR:

* Turn `target_pointer_width` into an integer and rename to `pointer_width`.
  The compiler only allowed three valid values for the width anyways.
  An integer is more natural for this value, and saves a few allocations
  and copies.
* Remove the `rustc_session::config::Config` wrapper and replace it with
  its inner member `Target`. Aka. no more `target.target`. This makes life so
  much easier, but it also causes a ton of downstream breakage.

Some changes of this PR were done using tooling. These tooling-made changes
were isolated to their own commits to make review easier.
It's best to review the PR commit-by-commit.

Miri PR: rust-lang/miri#1583

I request p=10 bors priority because of the breakage.

compiler/rustc_ast_lowering/src/expr.rs

@@ -985,7 +985,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             asm::InlineAsmReg::parse(
                                 sess.asm_arch?,
                                 |feature| sess.target_features.contains(&Symbol::intern(feature)),
-                                &sess.target.target,
+                                &sess.target,
                                 s,
                             )
                             .map_err(|e| {

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -796,7 +796,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
 
     fn visit_expr(&mut self, expr: &'a Expr) {
         match &expr.kind {
-            ExprKind::LlvmInlineAsm(..) if !self.session.target.target.options.allow_asm => {
+            ExprKind::LlvmInlineAsm(..) if !self.session.target.options.allow_asm => {
                 struct_span_err!(
                     self.session,
                     expr.span,

compiler/rustc_builtin_macros/src/test_harness.rs

@@ -37,7 +37,7 @@ struct TestCtxt<'a> {
 pub fn inject(sess: &Session, resolver: &mut dyn ResolverExpand, krate: &mut ast::Crate) {
     let span_diagnostic = sess.diagnostic();
     let panic_strategy = sess.panic_strategy();
-    let platform_panic_strategy = sess.target.target.options.panic_strategy;
+    let platform_panic_strategy = sess.target.options.panic_strategy;
 
     // Check for #![reexport_test_harness_main = "some_name"] which gives the
     // main test function the name `some_name` without hygiene. This needs to be

compiler/rustc_codegen_llvm/src/allocator.rs

@@ -16,10 +16,10 @@ pub(crate) unsafe fn codegen(
 ) {
     let llcx = &*mods.llcx;
     let llmod = mods.llmod();
-    let usize = match &tcx.sess.target.target.target_pointer_width[..] {
-        "16" => llvm::LLVMInt16TypeInContext(llcx),
-        "32" => llvm::LLVMInt32TypeInContext(llcx),
-        "64" => llvm::LLVMInt64TypeInContext(llcx),
+    let usize = match tcx.sess.target.pointer_width {
+        16 => llvm::LLVMInt16TypeInContext(llcx),
+        32 => llvm::LLVMInt32TypeInContext(llcx),
+        64 => llvm::LLVMInt64TypeInContext(llcx),
         tws => bug!("Unsupported target word size for int: {}", tws),
     };
     let i8 = llvm::LLVMInt8TypeInContext(llcx);
@@ -57,7 +57,7 @@ pub(crate) unsafe fn codegen(
         let name = format!("__rust_{}", method.name);
         let llfn = llvm::LLVMRustGetOrInsertFunction(llmod, name.as_ptr().cast(), name.len(), ty);
 
-        if tcx.sess.target.target.options.default_hidden_visibility {
+        if tcx.sess.target.options.default_hidden_visibility {
             llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
         }
         if tcx.sess.must_emit_unwind_tables() {
@@ -98,7 +98,7 @@ pub(crate) unsafe fn codegen(
     // -> ! DIFlagNoReturn
     llvm::Attribute::NoReturn.apply_llfn(llvm::AttributePlace::Function, llfn);
 
-    if tcx.sess.target.target.options.default_hidden_visibility {
+    if tcx.sess.target.options.default_hidden_visibility {
         llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
     }
     if tcx.sess.must_emit_unwind_tables() {

compiler/rustc_codegen_llvm/src/asm.rs

@@ -60,7 +60,7 @@ impl AsmBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
 
         // Default per-arch clobbers
         // Basically what clang does
-        let arch_clobbers = match &self.sess().target.target.arch[..] {
+        let arch_clobbers = match &self.sess().target.arch[..] {
             "x86" | "x86_64" => vec!["~{dirflag}", "~{fpsr}", "~{flags}"],
             "mips" | "mips64" => vec!["~{$1}"],
             _ => Vec::new(),

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -31,7 +31,7 @@ fn inline(cx: &CodegenCx<'ll, '_>, val: &'ll Value, inline: InlineAttr) {
         Hint => Attribute::InlineHint.apply_llfn(Function, val),
         Always => Attribute::AlwaysInline.apply_llfn(Function, val),
         Never => {
-            if cx.tcx().sess.target.target.arch != "amdgpu" {
+            if cx.tcx().sess.target.arch != "amdgpu" {
                 Attribute::NoInline.apply_llfn(Function, val);
             }
         }
@@ -91,8 +91,7 @@ fn set_instrument_function(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
         // The function name varies on platforms.
         // See test/CodeGen/mcount.c in clang.
         let mcount_name =
-            CString::new(cx.sess().target.target.options.target_mcount.as_str().as_bytes())
-                .unwrap();
+            CString::new(cx.sess().target.options.target_mcount.as_str().as_bytes()).unwrap();
 
         llvm::AddFunctionAttrStringValue(
             llfn,
@@ -106,7 +105,7 @@ fn set_instrument_function(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
 fn set_probestack(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
     // Only use stack probes if the target specification indicates that we
     // should be using stack probes
-    if !cx.sess().target.target.options.stack_probes {
+    if !cx.sess().target.options.stack_probes {
         return;
     }
 
@@ -175,7 +174,6 @@ pub fn llvm_target_features(sess: &Session) -> impl Iterator<Item = &str> {
         .split(',')
         .filter(|f| !RUSTC_SPECIFIC_FEATURES.iter().any(|s| f.contains(s)));
     sess.target
-        .target
         .options
         .features
         .split(',')
@@ -345,7 +343,7 @@ pub fn from_fn_attrs(cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value, instance: ty::
     // Note that currently the `wasm-import-module` doesn't do anything, but
     // eventually LLVM 7 should read this and ferry the appropriate import
     // module to the output file.
-    if cx.tcx.sess.target.target.arch == "wasm32" {
+    if cx.tcx.sess.target.arch == "wasm32" {
         if let Some(module) = wasm_import_module(cx.tcx, instance.def_id()) {
             llvm::AddFunctionAttrStringValue(
                 llfn,

compiler/rustc_codegen_llvm/src/back/archive.rs

@@ -206,7 +206,7 @@ impl<'a> LlvmArchiveBuilder<'a> {
     }
 
     fn llvm_archive_kind(&self) -> Result<ArchiveKind, &str> {
-        let kind = &*self.config.sess.target.target.options.archive_format;
+        let kind = &*self.config.sess.target.options.archive_format;
         kind.parse().map_err(|_| kind)
     }
 

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -128,40 +128,40 @@ pub fn target_machine_factory(
     let (opt_level, _) = to_llvm_opt_settings(optlvl);
     let use_softfp = sess.opts.cg.soft_float;
 
-    let ffunction_sections = sess.target.target.options.function_sections;
+    let ffunction_sections = sess.target.options.function_sections;
     let fdata_sections = ffunction_sections;
 
     let code_model = to_llvm_code_model(sess.code_model());
 
     let features = attributes::llvm_target_features(sess).collect::<Vec<_>>();
-    let mut singlethread = sess.target.target.options.singlethread;
+    let mut singlethread = sess.target.options.singlethread;
 
     // On the wasm target once the `atomics` feature is enabled that means that
     // we're no longer single-threaded, or otherwise we don't want LLVM to
     // lower atomic operations to single-threaded operations.
     if singlethread
-        && sess.target.target.llvm_target.contains("wasm32")
+        && sess.target.llvm_target.contains("wasm32")
         && sess.target_features.contains(&sym::atomics)
     {
         singlethread = false;
     }
 
-    let triple = SmallCStr::new(&sess.target.target.llvm_target);
+    let triple = SmallCStr::new(&sess.target.llvm_target);
     let cpu = SmallCStr::new(llvm_util::target_cpu(sess));
     let features = features.join(",");
     let features = CString::new(features).unwrap();
-    let abi = SmallCStr::new(&sess.target.target.options.llvm_abiname);
-    let trap_unreachable = sess.target.target.options.trap_unreachable;
+    let abi = SmallCStr::new(&sess.target.options.llvm_abiname);
+    let trap_unreachable = sess.target.options.trap_unreachable;
     let emit_stack_size_section = sess.opts.debugging_opts.emit_stack_sizes;
 
     let asm_comments = sess.asm_comments();
-    let relax_elf_relocations = sess.target.target.options.relax_elf_relocations;
+    let relax_elf_relocations = sess.target.options.relax_elf_relocations;
 
     let use_init_array = !sess
         .opts
         .debugging_opts
         .use_ctors_section
-        .unwrap_or(sess.target.target.options.use_ctors_section);
+        .unwrap_or(sess.target.options.use_ctors_section);
 
     Arc::new(move || {
         let tm = unsafe {

compiler/rustc_codegen_llvm/src/base.rs

@@ -60,7 +60,7 @@ pub fn write_compressed_metadata<'tcx>(
         unsafe { llvm::LLVMAddGlobal(metadata_llmod, common::val_ty(llconst), buf.as_ptr()) };
     unsafe {
         llvm::LLVMSetInitializer(llglobal, llconst);
-        let section_name = metadata::metadata_section_name(&tcx.sess.target.target);
+        let section_name = metadata::metadata_section_name(&tcx.sess.target);
         let name = SmallCStr::new(section_name);
         llvm::LLVMSetSection(llglobal, name.as_ptr());
 

compiler/rustc_codegen_llvm/src/builder.rs

@@ -308,8 +308,8 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         use rustc_middle::ty::{Int, Uint};
 
         let new_kind = match ty.kind() {
-            Int(t @ Isize) => Int(t.normalize(self.tcx.sess.target.ptr_width)),
-            Uint(t @ Usize) => Uint(t.normalize(self.tcx.sess.target.ptr_width)),
+            Int(t @ Isize) => Int(t.normalize(self.tcx.sess.target.pointer_width)),
+            Uint(t @ Usize) => Uint(t.normalize(self.tcx.sess.target.pointer_width)),
             t @ (Uint(_) | Int(_)) => t.clone(),
             _ => panic!("tried to get overflow intrinsic for op applied to non-int type"),
         };
@@ -541,7 +541,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     }
 
     fn range_metadata(&mut self, load: &'ll Value, range: Range<u128>) {
-        if self.sess().target.target.arch == "amdgpu" {
+        if self.sess().target.arch == "amdgpu" {
             // amdgpu/LLVM does something weird and thinks a i64 value is
             // split into a v2i32, halving the bitwidth LLVM expects,
             // tripping an assertion. So, for now, just disable this
@@ -671,7 +671,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         // WebAssembly has saturating floating point to integer casts if the
         // `nontrapping-fptoint` target feature is activated. We'll use those if
         // they are available.
-        if self.sess().target.target.arch == "wasm32"
+        if self.sess().target.arch == "wasm32"
             && self.sess().target_features.contains(&sym::nontrapping_dash_fptoint)
         {
             let src_ty = self.cx.val_ty(val);
@@ -696,7 +696,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         // WebAssembly has saturating floating point to integer casts if the
         // `nontrapping-fptoint` target feature is activated. We'll use those if
         // they are available.
-        if self.sess().target.target.arch == "wasm32"
+        if self.sess().target.arch == "wasm32"
             && self.sess().target_features.contains(&sym::nontrapping_dash_fptoint)
         {
             let src_ty = self.cx.val_ty(val);
@@ -1427,7 +1427,7 @@ impl Builder<'a, 'll, 'tcx> {
     }
 
     fn wasm_and_missing_nontrapping_fptoint(&self) -> bool {
-        self.sess().target.target.arch == "wasm32"
+        self.sess().target.arch == "wasm32"
             && !self.sess().target_features.contains(&sym::nontrapping_dash_fptoint)
     }
 }

compiler/rustc_codegen_llvm/src/callee.rs

@@ -176,7 +176,7 @@ pub fn get_fn(cx: &CodegenCx<'ll, 'tcx>, instance: Instance<'tcx>) -> &'ll Value
         // should use dllimport for functions.
         if cx.use_dll_storage_attrs
             && tcx.is_dllimport_foreign_item(instance_def_id)
-            && tcx.sess.target.target.target_env != "gnu"
+            && tcx.sess.target.target_env != "gnu"
         {
             unsafe {
                 llvm::LLVMSetDLLStorageClass(llfn, llvm::DLLStorageClass::DllImport);

compiler/rustc_codegen_llvm/src/consts.rs

@@ -92,7 +92,7 @@ fn set_global_alignment(cx: &CodegenCx<'ll, '_>, gv: &'ll Value, mut align: Alig
     // The target may require greater alignment for globals than the type does.
     // Note: GCC and Clang also allow `__attribute__((aligned))` on variables,
     // which can force it to be smaller.  Rust doesn't support this yet.
-    if let Some(min) = cx.sess().target.target.options.min_global_align {
+    if let Some(min) = cx.sess().target.options.min_global_align {
         match Align::from_bits(min) {
             Ok(min) => align = align.max(min),
             Err(err) => {
@@ -283,7 +283,7 @@ impl CodegenCx<'ll, 'tcx> {
             // argument validation.
             debug_assert!(
                 !(self.tcx.sess.opts.cg.linker_plugin_lto.enabled()
-                    && self.tcx.sess.target.target.options.is_like_windows
+                    && self.tcx.sess.target.options.is_like_windows
                     && self.tcx.sess.opts.cg.prefer_dynamic)
             );
 
@@ -437,7 +437,7 @@ impl StaticMethods for CodegenCx<'ll, 'tcx> {
                 // will use load-unaligned instructions instead, and thus avoiding the crash.
                 //
                 // We could remove this hack whenever we decide to drop macOS 10.10 support.
-                if self.tcx.sess.target.target.options.is_like_osx {
+                if self.tcx.sess.target.options.is_like_osx {
                     // The `inspect` method is okay here because we checked relocations, and
                     // because we are doing this access to inspect the final interpreter state
                     // (not as part of the interpreter execution).

compiler/rustc_codegen_llvm/src/context.rs

@@ -118,18 +118,18 @@ pub unsafe fn create_module(
     let mod_name = SmallCStr::new(mod_name);
     let llmod = llvm::LLVMModuleCreateWithNameInContext(mod_name.as_ptr(), llcx);
 
-    let mut target_data_layout = sess.target.target.data_layout.clone();
+    let mut target_data_layout = sess.target.data_layout.clone();
     if llvm_util::get_major_version() < 9 {
         target_data_layout = strip_function_ptr_alignment(target_data_layout);
     }
     if llvm_util::get_major_version() < 10 {
-        if sess.target.target.arch == "x86" || sess.target.target.arch == "x86_64" {
+        if sess.target.arch == "x86" || sess.target.arch == "x86_64" {
             target_data_layout = strip_x86_address_spaces(target_data_layout);
         }
     }
 
     // Ensure the data-layout values hardcoded remain the defaults.
-    if sess.target.target.options.is_builtin {
+    if sess.target.options.is_builtin {
         let tm = crate::back::write::create_informational_target_machine(tcx.sess);
         llvm::LLVMRustSetDataLayoutFromTargetMachine(llmod, tm);
         llvm::LLVMRustDisposeTargetMachine(tm);
@@ -160,7 +160,7 @@ pub unsafe fn create_module(
             bug!(
                 "data-layout for builtin `{}` target, `{}`, \
                   differs from LLVM default, `{}`",
-                sess.target.target.llvm_target,
+                sess.target.llvm_target,
                 target_data_layout,
                 llvm_data_layout
             );
@@ -170,7 +170,7 @@ pub unsafe fn create_module(
     let data_layout = SmallCStr::new(&target_data_layout);
     llvm::LLVMSetDataLayout(llmod, data_layout.as_ptr());
 
-    let llvm_target = SmallCStr::new(&sess.target.target.llvm_target);
+    let llvm_target = SmallCStr::new(&sess.target.llvm_target);
     llvm::LLVMRustSetNormalizedTarget(llmod, llvm_target.as_ptr());
 
     if sess.relocation_model() == RelocModel::Pic {
@@ -190,7 +190,7 @@ pub unsafe fn create_module(
     }
 
     // Control Flow Guard is currently only supported by the MSVC linker on Windows.
-    if sess.target.target.options.is_like_msvc {
+    if sess.target.options.is_like_msvc {
         match sess.opts.cg.control_flow_guard {
             CFGuard::Disabled => {}
             CFGuard::NoChecks => {
@@ -265,7 +265,7 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
         // linker will take care of everything. Fixing this problem will likely
         // require adding a few attributes to Rust itself (feature gated at the
         // start) and then strongly recommending static linkage on Windows!
-        let use_dll_storage_attrs = tcx.sess.target.target.options.is_like_windows;
+        let use_dll_storage_attrs = tcx.sess.target.options.is_like_windows;
 
         let check_overflow = tcx.sess.overflow_checks();
 
@@ -839,7 +839,7 @@ impl CodegenCx<'b, 'tcx> {
             return eh_catch_typeinfo;
         }
         let tcx = self.tcx;
-        assert!(self.sess().target.target.options.is_like_emscripten);
+        assert!(self.sess().target.options.is_like_emscripten);
         let eh_catch_typeinfo = match tcx.lang_items().eh_catch_typeinfo() {
             Some(def_id) => self.get_static(def_id),
             _ => {
@@ -878,7 +878,7 @@ impl HasDataLayout for CodegenCx<'ll, 'tcx> {
 
 impl HasTargetSpec for CodegenCx<'ll, 'tcx> {
     fn target_spec(&self) -> &Target {
-        &self.tcx.sess.target.target
+        &self.tcx.sess.target
     }
 }
 

compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs

@@ -67,5 +67,5 @@ pub fn needs_gdb_debug_scripts_section(cx: &CodegenCx<'_, '_>) -> bool {
 
     !omit_gdb_pretty_printer_section
         && cx.sess().opts.debuginfo != DebugInfo::None
-        && cx.sess().target.target.options.emit_debug_gdb_scripts
+        && cx.sess().target.options.emit_debug_gdb_scripts
 }

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -874,7 +874,7 @@ fn basic_type_metadata(cx: &CodegenCx<'ll, 'tcx>, t: Ty<'tcx>) -> &'ll DIType {
 
     // When targeting MSVC, emit MSVC style type names for compatibility with
     // .natvis visualizers (and perhaps other existing native debuggers?)
-    let msvc_like_names = cx.tcx.sess.target.target.options.is_like_msvc;
+    let msvc_like_names = cx.tcx.sess.target.options.is_like_msvc;
 
     let (name, encoding) = match t.kind() {
         ty::Never => ("!", DW_ATE_unsigned),
@@ -985,7 +985,7 @@ pub fn compile_unit_metadata(
     // if multiple object files with the same `DW_AT_name` are linked together.
     // As a workaround we generate unique names for each object file. Those do
     // not correspond to an actual source file but that should be harmless.
-    if tcx.sess.target.target.options.is_like_osx {
+    if tcx.sess.target.options.is_like_osx {
         name_in_debuginfo.push("@");
         name_in_debuginfo.push(codegen_unit_name);
     }
@@ -1401,7 +1401,7 @@ fn prepare_union_metadata(
 /// on MSVC we have to use the fallback mode, because LLVM doesn't
 /// lower variant parts to PDB.
 fn use_enum_fallback(cx: &CodegenCx<'_, '_>) -> bool {
-    cx.sess().target.target.options.is_like_msvc
+    cx.sess().target.options.is_like_msvc
 }
 
 // FIXME(eddyb) maybe precompute this? Right now it's computed once

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -120,12 +120,12 @@ pub fn finalize(cx: &CodegenCx<'_, '_>) {
         // for macOS to understand. For more info see #11352
         // This can be overridden using --llvm-opts -dwarf-version,N.
         // Android has the same issue (#22398)
-        if let Some(version) = cx.sess().target.target.options.dwarf_version {
+        if let Some(version) = cx.sess().target.options.dwarf_version {
             llvm::LLVMRustAddModuleFlag(cx.llmod, "Dwarf Version\0".as_ptr().cast(), version)
         }
 
         // Indicate that we want CodeView debug information on MSVC
-        if cx.sess().target.target.options.is_like_msvc {
+        if cx.sess().target.options.is_like_msvc {
             llvm::LLVMRustAddModuleFlag(cx.llmod, "CodeView\0".as_ptr().cast(), 1)
         }
 
@@ -346,7 +346,7 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             });
 
             // Arguments types
-            if cx.sess().target.target.options.is_like_msvc {
+            if cx.sess().target.options.is_like_msvc {
                 // FIXME(#42800):
                 // There is a bug in MSDIA that leads to a crash when it encounters
                 // a fixed-size array of `u8` or something zero-sized in a