Rollup merge of #111647 - klensy:cstr, r=oli-obk

use c literals in compiler and library

Use c literals #108801 in compiler and library

currently blocked on:
* <strike>rustfmt: don't know how to format c literals</strike> nope, nightly one works.
* <strike>bootstrap</strike>

r? `@ghost`
`@rustbot` blocked

Author: matthiaskrgr

Cargo.lock

@@ -871,16 +871,6 @@ dependencies = [
  "typenum",
 ]
 
-[[package]]
-name = "cstr"
-version = "0.2.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c11a39d776a3b35896711da8a04dc1835169dcd36f710878187637314e47941b"
-dependencies = [
- "proc-macro2",
- "quote",
-]
-
 [[package]]
 name = "ctrlc"
 version = "3.3.1"
@@ -3179,7 +3169,6 @@ name = "rustc_codegen_llvm"
 version = "0.0.0"
 dependencies = [
  "bitflags",
- "cstr",
  "libc",
  "measureme",
  "object 0.31.1",

compiler/rustc_codegen_llvm/Cargo.toml

@@ -8,7 +8,6 @@ test = false
 
 [dependencies]
 bitflags = "1.0"
-cstr = "0.2"
 libc = "0.2"
 measureme = "10.0.0"
 object = { version = "0.31.1", default-features = false, features = [

compiler/rustc_codegen_llvm/src/allocator.rs

@@ -77,7 +77,7 @@ pub(crate) unsafe fn codegen(
                 llvm::LLVMRustGetOrInsertFunction(llmod, callee.as_ptr().cast(), callee.len(), ty);
             llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden);
 
-            let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, "entry\0".as_ptr().cast());
+            let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, c"entry".as_ptr().cast());
 
             let llbuilder = llvm::LLVMCreateBuilderInContext(llcx);
             llvm::LLVMPositionBuilderAtEnd(llbuilder, llbb);
@@ -129,7 +129,7 @@ pub(crate) unsafe fn codegen(
     attributes::apply_to_llfn(callee, llvm::AttributePlace::Function, &[no_return]);
     llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden);
 
-    let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, "entry\0".as_ptr().cast());
+    let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, c"entry".as_ptr().cast());
 
     let llbuilder = llvm::LLVMCreateBuilderInContext(llcx);
     llvm::LLVMPositionBuilderAtEnd(llbuilder, llbb);

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -595,7 +595,7 @@ pub(crate) fn run_pass_manager(
             llvm::LLVMRustAddModuleFlag(
                 module.module_llvm.llmod(),
                 llvm::LLVMModFlagBehavior::Error,
-                "LTOPostLink\0".as_ptr().cast(),
+                c"LTOPostLink".as_ptr().cast(),
                 1,
             );
         }

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -891,11 +891,11 @@ unsafe fn embed_bitcode(
         let llglobal = llvm::LLVMAddGlobal(
             llmod,
             common::val_ty(llconst),
-            "rustc.embedded.module\0".as_ptr().cast(),
+            c"rustc.embedded.module".as_ptr().cast(),
         );
         llvm::LLVMSetInitializer(llglobal, llconst);
 
-        let section = if is_apple { "__LLVM,__bitcode\0" } else { ".llvmbc\0" };
+        let section = if is_apple { c"__LLVM,__bitcode" } else { c".llvmbc" };
         llvm::LLVMSetSection(llglobal, section.as_ptr().cast());
         llvm::LLVMRustSetLinkage(llglobal, llvm::Linkage::PrivateLinkage);
         llvm::LLVMSetGlobalConstant(llglobal, llvm::True);
@@ -904,10 +904,10 @@ unsafe fn embed_bitcode(
         let llglobal = llvm::LLVMAddGlobal(
             llmod,
             common::val_ty(llconst),
-            "rustc.embedded.cmdline\0".as_ptr().cast(),
+            c"rustc.embedded.cmdline".as_ptr().cast(),
         );
         llvm::LLVMSetInitializer(llglobal, llconst);
-        let section = if is_apple { "__LLVM,__cmdline\0" } else { ".llvmcmd\0" };
+        let section = if is_apple { c"__LLVM,__cmdline" } else { c".llvmcmd" };
         llvm::LLVMSetSection(llglobal, section.as_ptr().cast());
         llvm::LLVMRustSetLinkage(llglobal, llvm::Linkage::PrivateLinkage);
     } else {

compiler/rustc_codegen_llvm/src/base.rs

@@ -19,8 +19,6 @@ use crate::context::CodegenCx;
 use crate::llvm;
 use crate::value::Value;
 
-use cstr::cstr;
-
 use rustc_codegen_ssa::base::maybe_create_entry_wrapper;
 use rustc_codegen_ssa::mono_item::MonoItemExt;
 use rustc_codegen_ssa::traits::*;
@@ -110,11 +108,11 @@ pub fn compile_codegen_unit(tcx: TyCtxt<'_>, cgu_name: Symbol) -> (ModuleCodegen
 
             // Create the llvm.used and llvm.compiler.used variables.
             if !cx.used_statics.borrow().is_empty() {
-                cx.create_used_variable_impl(cstr!("llvm.used"), &*cx.used_statics.borrow());
+                cx.create_used_variable_impl(c"llvm.used", &*cx.used_statics.borrow());
             }
             if !cx.compiler_used_statics.borrow().is_empty() {
                 cx.create_used_variable_impl(
-                    cstr!("llvm.compiler.used"),
+                    c"llvm.compiler.used",
                     &*cx.compiler_used_statics.borrow(),
                 );
             }

compiler/rustc_codegen_llvm/src/builder.rs

@@ -6,7 +6,6 @@ use crate::llvm::{self, AtomicOrdering, AtomicRmwBinOp, BasicBlock, False, True}
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
-use cstr::cstr;
 use libc::{c_char, c_uint};
 use rustc_codegen_ssa::common::{IntPredicate, RealPredicate, SynchronizationScope, TypeKind};
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
@@ -25,7 +24,6 @@ use rustc_symbol_mangling::typeid::{kcfi_typeid_for_fnabi, typeid_for_fnabi, Typ
 use rustc_target::abi::{self, call::FnAbi, Align, Size, WrappingRange};
 use rustc_target::spec::{HasTargetSpec, SanitizerSet, Target};
 use std::borrow::Cow;
-use std::ffi::CStr;
 use std::iter;
 use std::ops::Deref;
 use std::ptr;
@@ -45,13 +43,10 @@ impl Drop for Builder<'_, '_, '_> {
     }
 }
 
-// FIXME(eddyb) use a checked constructor when they become `const fn`.
-const EMPTY_C_STR: &CStr = unsafe { CStr::from_bytes_with_nul_unchecked(b"\0") };
-
 /// Empty string, to be used where LLVM expects an instruction name, indicating
 /// that the instruction is to be left unnamed (i.e. numbered, in textual IR).
 // FIXME(eddyb) pass `&CStr` directly to FFI once it's a thin pointer.
-const UNNAMED: *const c_char = EMPTY_C_STR.as_ptr();
+const UNNAMED: *const c_char = c"".as_ptr();
 
 impl<'ll, 'tcx> BackendTypes for Builder<'_, 'll, 'tcx> {
     type Value = <CodegenCx<'ll, 'tcx> as BackendTypes>::Value;
@@ -1010,14 +1005,13 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     }
 
     fn cleanup_pad(&mut self, parent: Option<&'ll Value>, args: &[&'ll Value]) -> Funclet<'ll> {
-        let name = cstr!("cleanuppad");
         let ret = unsafe {
             llvm::LLVMBuildCleanupPad(
                 self.llbuilder,
                 parent,
                 args.as_ptr(),
                 args.len() as c_uint,
-                name.as_ptr(),
+                c"cleanuppad".as_ptr(),
             )
         };
         Funclet::new(ret.expect("LLVM does not have support for cleanuppad"))
@@ -1031,14 +1025,13 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     }
 
     fn catch_pad(&mut self, parent: &'ll Value, args: &[&'ll Value]) -> Funclet<'ll> {
-        let name = cstr!("catchpad");
         let ret = unsafe {
             llvm::LLVMBuildCatchPad(
                 self.llbuilder,
                 parent,
                 args.as_ptr(),
                 args.len() as c_uint,
-                name.as_ptr(),
+                c"catchpad".as_ptr(),
             )
         };
         Funclet::new(ret.expect("LLVM does not have support for catchpad"))
@@ -1050,14 +1043,13 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         unwind: Option<&'ll BasicBlock>,
         handlers: &[&'ll BasicBlock],
     ) -> &'ll Value {
-        let name = cstr!("catchswitch");
         let ret = unsafe {
             llvm::LLVMBuildCatchSwitch(
                 self.llbuilder,
                 parent,
                 unwind,
                 handlers.len() as c_uint,
-                name.as_ptr(),
+                c"catchswitch".as_ptr(),
             )
         };
         let ret = ret.expect("LLVM does not have support for catchswitch");

compiler/rustc_codegen_llvm/src/consts.rs

@@ -8,7 +8,6 @@ use crate::llvm::{self, True};
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
-use cstr::cstr;
 use rustc_codegen_ssa::traits::*;
 use rustc_hir::def_id::DefId;
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
@@ -482,9 +481,9 @@ impl<'ll> StaticMethods for CodegenCx<'ll, '_> {
                             .all(|&byte| byte == 0);
 
                     let sect_name = if all_bytes_are_zero {
-                        cstr!("__DATA,__thread_bss")
+                        c"__DATA,__thread_bss"
                     } else {
-                        cstr!("__DATA,__thread_data")
+                        c"__DATA,__thread_data"
                     };
                     llvm::LLVMSetSection(g, sect_name.as_ptr());
                 }
@@ -513,7 +512,7 @@ impl<'ll> StaticMethods for CodegenCx<'ll, '_> {
                     let val = llvm::LLVMMetadataAsValue(self.llcx, meta);
                     llvm::LLVMAddNamedMetadataOperand(
                         self.llmod,
-                        "wasm.custom_sections\0".as_ptr().cast(),
+                        c"wasm.custom_sections".as_ptr().cast(),
                         val,
                     );
                 }

compiler/rustc_codegen_llvm/src/context.rs

@@ -8,7 +8,6 @@ use crate::llvm_util;
 use crate::type_::Type;
 use crate::value::Value;
 
-use cstr::cstr;
 use rustc_codegen_ssa::base::wants_msvc_seh;
 use rustc_codegen_ssa::traits::*;
 use rustc_data_structures::base_n;
@@ -224,36 +223,42 @@ pub unsafe fn create_module<'ll>(
     // If skipping the PLT is enabled, we need to add some module metadata
     // to ensure intrinsic calls don't use it.
     if !sess.needs_plt() {
-        let avoid_plt = "RtLibUseGOT\0".as_ptr().cast();
-        llvm::LLVMRustAddModuleFlag(llmod, llvm::LLVMModFlagBehavior::Warning, avoid_plt, 1);
+        llvm::LLVMRustAddModuleFlag(
+            llmod,
+            llvm::LLVMModFlagBehavior::Warning,
+            c"RtLibUseGOT".as_ptr().cast(),
+            1,
+        );
     }
 
     // Enable canonical jump tables if CFI is enabled. (See https://reviews.llvm.org/D65629.)
     if sess.is_sanitizer_cfi_canonical_jump_tables_enabled() && sess.is_sanitizer_cfi_enabled() {
-        let canonical_jump_tables = "CFI Canonical Jump Tables\0".as_ptr().cast();
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
-            canonical_jump_tables,
+            c"CFI Canonical Jump Tables".as_ptr().cast(),
             1,
         );
     }
 
     // Enable LTO unit splitting if specified or if CFI is enabled. (See https://reviews.llvm.org/D53891.)
     if sess.is_split_lto_unit_enabled() || sess.is_sanitizer_cfi_enabled() {
-        let enable_split_lto_unit = "EnableSplitLTOUnit\0".as_ptr().cast();
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
-            enable_split_lto_unit,
+            c"EnableSplitLTOUnit".as_ptr().cast(),
             1,
         );
     }
 
     // Add "kcfi" module flag if KCFI is enabled. (See https://reviews.llvm.org/D119296.)
     if sess.is_sanitizer_kcfi_enabled() {
-        let kcfi = "kcfi\0".as_ptr().cast();
-        llvm::LLVMRustAddModuleFlag(llmod, llvm::LLVMModFlagBehavior::Override, kcfi, 1);
+        llvm::LLVMRustAddModuleFlag(
+            llmod,
+            llvm::LLVMModFlagBehavior::Override,
+            c"kcfi".as_ptr().cast(),
+            1,
+        );
     }
 
     // Control Flow Guard is currently only supported by the MSVC linker on Windows.
@@ -265,7 +270,7 @@ pub unsafe fn create_module<'ll>(
                 llvm::LLVMRustAddModuleFlag(
                     llmod,
                     llvm::LLVMModFlagBehavior::Warning,
-                    "cfguard\0".as_ptr() as *const _,
+                    c"cfguard".as_ptr() as *const _,
                     1,
                 )
             }
@@ -274,7 +279,7 @@ pub unsafe fn create_module<'ll>(
                 llvm::LLVMRustAddModuleFlag(
                     llmod,
                     llvm::LLVMModFlagBehavior::Warning,
-                    "cfguard\0".as_ptr() as *const _,
+                    c"cfguard".as_ptr() as *const _,
                     2,
                 )
             }
@@ -292,26 +297,26 @@ pub unsafe fn create_module<'ll>(
             llvm::LLVMRustAddModuleFlag(
                 llmod,
                 behavior,
-                "branch-target-enforcement\0".as_ptr().cast(),
+                c"branch-target-enforcement".as_ptr().cast(),
                 bti.into(),
             );
             llvm::LLVMRustAddModuleFlag(
                 llmod,
                 behavior,
-                "sign-return-address\0".as_ptr().cast(),
+                c"sign-return-address".as_ptr().cast(),
                 pac_ret.is_some().into(),
             );
             let pac_opts = pac_ret.unwrap_or(PacRet { leaf: false, key: PAuthKey::A });
             llvm::LLVMRustAddModuleFlag(
                 llmod,
                 behavior,
-                "sign-return-address-all\0".as_ptr().cast(),
+                c"sign-return-address-all".as_ptr().cast(),
                 pac_opts.leaf.into(),
             );
             llvm::LLVMRustAddModuleFlag(
                 llmod,
                 behavior,
-                "sign-return-address-with-bkey\0".as_ptr().cast(),
+                c"sign-return-address-with-bkey".as_ptr().cast(),
                 u32::from(pac_opts.key == PAuthKey::B),
             );
         } else {
@@ -327,15 +332,15 @@ pub unsafe fn create_module<'ll>(
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
-            "cf-protection-branch\0".as_ptr().cast(),
+            c"cf-protection-branch".as_ptr().cast(),
             1,
         )
     }
     if let CFProtection::Return | CFProtection::Full = sess.opts.unstable_opts.cf_protection {
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
-            "cf-protection-return\0".as_ptr().cast(),
+            c"cf-protection-return".as_ptr().cast(),
             1,
         )
     }
@@ -344,7 +349,7 @@ pub unsafe fn create_module<'ll>(
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Error,
-            "Virtual Function Elim\0".as_ptr().cast(),
+            c"Virtual Function Elim".as_ptr().cast(),
             1,
         );
     }
@@ -476,14 +481,13 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
     }
 
     pub(crate) fn create_used_variable_impl(&self, name: &'static CStr, values: &[&'ll Value]) {
-        let section = cstr!("llvm.metadata");
         let array = self.const_array(self.type_ptr_to(self.type_i8()), values);
 
         unsafe {
             let g = llvm::LLVMAddGlobal(self.llmod, self.val_ty(array), name.as_ptr());
             llvm::LLVMSetInitializer(g, array);
             llvm::LLVMRustSetLinkage(g, llvm::Linkage::AppendingLinkage);
-            llvm::LLVMSetSection(g, section.as_ptr());
+            llvm::LLVMSetSection(g, c"llvm.metadata".as_ptr());
         }
     }
 }

compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs

@@ -38,7 +38,6 @@ pub fn get_or_insert_gdb_debug_scripts_section_global<'ll>(cx: &CodegenCx<'ll, '
         unsafe { llvm::LLVMGetNamedGlobal(cx.llmod, c_section_var_name.as_ptr().cast()) };
 
     section_var.unwrap_or_else(|| {
-        let section_name = b".debug_gdb_scripts\0";
         let mut section_contents = Vec::new();
 
         // Add the pretty printers for the standard library first.
@@ -71,7 +70,7 @@ pub fn get_or_insert_gdb_debug_scripts_section_global<'ll>(cx: &CodegenCx<'ll, '
             let section_var = cx
                 .define_global(section_var_name, llvm_type)
                 .unwrap_or_else(|| bug!("symbol `{}` is already defined", section_var_name));
-            llvm::LLVMSetSection(section_var, section_name.as_ptr().cast());
+            llvm::LLVMSetSection(section_var, c".debug_gdb_scripts".as_ptr().cast());
             llvm::LLVMSetInitializer(section_var, cx.const_bytes(section_contents));
             llvm::LLVMSetGlobalConstant(section_var, llvm::True);
             llvm::LLVMSetUnnamedAddress(section_var, llvm::UnnamedAddr::Global);

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -20,7 +20,6 @@ use crate::llvm::debuginfo::{
 };
 use crate::value::Value;
 
-use cstr::cstr;
 use rustc_codegen_ssa::debuginfo::type_names::cpp_like_debuginfo;
 use rustc_codegen_ssa::debuginfo::type_names::VTableNameKind;
 use rustc_codegen_ssa::traits::*;
@@ -812,7 +811,6 @@ pub fn build_compile_unit_di_node<'ll, 'tcx>(
 
     let name_in_debuginfo = name_in_debuginfo.to_string_lossy();
     let work_dir = tcx.sess.opts.working_dir.to_string_lossy(FileNameDisplayPreference::Remapped);
-    let flags = "\0";
     let output_filenames = tcx.output_filenames(());
     let split_name = if tcx.sess.target_can_use_split_dwarf() {
         output_filenames
@@ -849,7 +847,7 @@ pub fn build_compile_unit_di_node<'ll, 'tcx>(
             producer.as_ptr().cast(),
             producer.len(),
             tcx.sess.opts.optimize != config::OptLevel::No,
-            flags.as_ptr().cast(),
+            c"".as_ptr().cast(),
             0,
             // NB: this doesn't actually have any perceptible effect, it seems. LLVM will instead
             // put the path supplied to `MCSplitDwarfFile` into the debug info of the final
@@ -878,8 +876,7 @@ pub fn build_compile_unit_di_node<'ll, 'tcx>(
             );
             let val = llvm::LLVMMetadataAsValue(debug_context.llcontext, gcov_metadata);
 
-            let llvm_gcov_ident = cstr!("llvm.gcov");
-            llvm::LLVMAddNamedMetadataOperand(debug_context.llmod, llvm_gcov_ident.as_ptr(), val);
+            llvm::LLVMAddNamedMetadataOperand(debug_context.llmod, c"llvm.gcov".as_ptr(), val);
         }
 
         // Insert `llvm.ident` metadata on the wasm targets since that will
@@ -892,7 +889,7 @@ pub fn build_compile_unit_di_node<'ll, 'tcx>(
             );
             llvm::LLVMAddNamedMetadataOperand(
                 debug_context.llmod,
-                cstr!("llvm.ident").as_ptr(),
+                c"llvm.ident".as_ptr(),
                 llvm::LLVMMDNodeInContext(debug_context.llcontext, &name_metadata, 1),
             );
         }

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -113,25 +113,24 @@ impl<'ll, 'tcx> CodegenUnitDebugContext<'ll, 'tcx> {
                 llvm::LLVMRustAddModuleFlag(
                     self.llmod,
                     llvm::LLVMModFlagBehavior::Warning,
-                    "Dwarf Version\0".as_ptr().cast(),
+                    c"Dwarf Version".as_ptr().cast(),
                     dwarf_version,
                 );
             } else {
                 // Indicate that we want CodeView debug information on MSVC
                 llvm::LLVMRustAddModuleFlag(
                     self.llmod,
                     llvm::LLVMModFlagBehavior::Warning,
-                    "CodeView\0".as_ptr().cast(),
+                    c"CodeView".as_ptr().cast(),
                     1,
                 )
             }
 
             // Prevent bitcode readers from deleting the debug info.
-            let ptr = "Debug Info Version\0".as_ptr();
             llvm::LLVMRustAddModuleFlag(
                 self.llmod,
                 llvm::LLVMModFlagBehavior::Warning,
-                ptr.cast(),
+                c"Debug Info Version".as_ptr().cast(),
                 llvm::LLVMRustDebugMetadataVersion(),
             );
         }

compiler/rustc_codegen_llvm/src/lib.rs

@@ -11,6 +11,7 @@
 #![feature(let_chains)]
 #![feature(never_type)]
 #![feature(impl_trait_in_assoc_type)]
+#![feature(c_str_literals)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]

library/std/src/lib.rs

@@ -240,6 +240,7 @@
 #![feature(allocator_internals)]
 #![feature(allow_internal_unsafe)]
 #![feature(allow_internal_unstable)]
+#![feature(c_str_literals)]
 #![feature(c_unwind)]
 #![feature(cfg_target_thread_local)]
 #![feature(concat_idents)]

library/std/src/sys/unix/args.rs

@@ -242,13 +242,15 @@ mod imp {
         let mut res = Vec::new();
 
         unsafe {
-            let process_info_sel = sel_registerName("processInfo\0".as_ptr());
-            let arguments_sel = sel_registerName("arguments\0".as_ptr());
-            let utf8_sel = sel_registerName("UTF8String\0".as_ptr());
-            let count_sel = sel_registerName("count\0".as_ptr());
-            let object_at_sel = sel_registerName("objectAtIndex:\0".as_ptr());
-
-            let klass = objc_getClass("NSProcessInfo\0".as_ptr());
+            let process_info_sel =
+                sel_registerName(c"processInfo".as_ptr() as *const libc::c_uchar);
+            let arguments_sel = sel_registerName(c"arguments".as_ptr() as *const libc::c_uchar);
+            let utf8_sel = sel_registerName(c"UTF8String".as_ptr() as *const libc::c_uchar);
+            let count_sel = sel_registerName(c"count".as_ptr() as *const libc::c_uchar);
+            let object_at_sel =
+                sel_registerName(c"objectAtIndex:".as_ptr() as *const libc::c_uchar);
+
+            let klass = objc_getClass(c"NSProcessInfo".as_ptr() as *const libc::c_uchar);
             let info = objc_msgSend(klass, process_info_sel);
             let args = objc_msgSend(info, arguments_sel);
 

library/std/src/sys/unix/fs.rs

@@ -1063,7 +1063,7 @@ impl File {
         cfg_has_statx! {
             if let Some(ret) = unsafe { try_statx(
                 fd,
-                b"\0" as *const _ as *const c_char,
+                c"".as_ptr() as *const c_char,
                 libc::AT_EMPTY_PATH | libc::AT_STATX_SYNC_AS_STAT,
                 libc::STATX_ALL,
             ) } {

library/std/src/sys/unix/mod.rs

@@ -1,6 +1,5 @@
 #![allow(missing_docs, nonstandard_style)]
 
-use crate::ffi::CStr;
 use crate::io::ErrorKind;
 
 pub use self::rand::hashmap_random_keys;
@@ -75,7 +74,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
     // thread-id for the main thread and so renaming the main thread will rename the
     // process and we only want to enable this on platforms we've tested.
     if cfg!(target_os = "macos") {
-        thread::Thread::set_name(&CStr::from_bytes_with_nul_unchecked(b"main\0"));
+        thread::Thread::set_name(&c"main");
     }
 
     unsafe fn sanitize_standard_fds() {
@@ -121,7 +120,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
                 if pfd.revents & libc::POLLNVAL == 0 {
                     continue;
                 }
-                if open64("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
+                if open64(c"/dev/null".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
                     // If the stream is closed but we failed to reopen it, abort the
                     // process. Otherwise we wouldn't preserve the safety of
                     // operations on the corresponding Rust object Stdin, Stdout, or
@@ -151,7 +150,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
             use libc::open64;
             for fd in 0..3 {
                 if libc::fcntl(fd, libc::F_GETFD) == -1 && errno() == libc::EBADF {
-                    if open64("/dev/null\0".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
+                    if open64(c"/dev/null".as_ptr().cast(), libc::O_RDWR, 0) == -1 {
                         // If the stream is closed but we failed to reopen it, abort the
                         // process. Otherwise we wouldn't preserve the safety of
                         // operations on the corresponding Rust object Stdin, Stdout, or

library/std/src/sys/unix/process/process_common.rs

@@ -24,11 +24,11 @@ cfg_if::cfg_if! {
     if #[cfg(target_os = "fuchsia")] {
         // fuchsia doesn't have /dev/null
     } else if #[cfg(target_os = "redox")] {
-        const DEV_NULL: &str = "null:\0";
+        const DEV_NULL: &CStr = c"null:";
     } else if #[cfg(target_os = "vxworks")] {
-        const DEV_NULL: &str = "/null\0";
+        const DEV_NULL: &CStr = c"/null";
     } else {
-        const DEV_NULL: &str = "/dev/null\0";
+        const DEV_NULL: &CStr = c"/dev/null";
     }
 }
 
@@ -474,8 +474,7 @@ impl Stdio {
                 let mut opts = OpenOptions::new();
                 opts.read(readable);
                 opts.write(!readable);
-                let path = unsafe { CStr::from_ptr(DEV_NULL.as_ptr() as *const _) };
-                let fd = File::open_c(&path, &opts)?;
+                let fd = File::open_c(DEV_NULL, &opts)?;
                 Ok((ChildStdio::Owned(fd.into_inner()), None))
             }
 

library/std/src/sys/unix/thread.rs

@@ -163,10 +163,9 @@ impl Thread {
     #[cfg(target_os = "netbsd")]
     pub fn set_name(name: &CStr) {
         unsafe {
-            let cname = CStr::from_bytes_with_nul_unchecked(b"%s\0".as_slice());
             let res = libc::pthread_setname_np(
                 libc::pthread_self(),
-                cname.as_ptr(),
+                c"%s".as_ptr(),
                 name.as_ptr() as *mut libc::c_void,
             );
             debug_assert_eq!(res, 0);

library/std/src/sys/windows/c.rs

@@ -317,7 +317,7 @@ pub unsafe fn NtWriteFile(
 // Functions that aren't available on every version of Windows that we support,
 // but we still use them and just provide some form of a fallback implementation.
 compat_fn_with_fallback! {
-    pub static KERNEL32: &CStr = ansi_str!("kernel32");
+    pub static KERNEL32: &CStr = c"kernel32";
 
     // >= Win10 1607
     // https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-setthreaddescription
@@ -350,7 +350,7 @@ compat_fn_optional! {
 }
 
 compat_fn_with_fallback! {
-    pub static NTDLL: &CStr = ansi_str!("ntdll");
+    pub static NTDLL: &CStr = c"ntdll";
 
     pub fn NtCreateKeyedEvent(
         KeyedEventHandle: LPHANDLE,

library/std/src/sys/windows/compat.rs

@@ -228,9 +228,9 @@ macro_rules! compat_fn_optional {
 /// Load all needed functions from "api-ms-win-core-synch-l1-2-0".
 pub(super) fn load_synch_functions() {
     fn try_load() -> Option<()> {
-        const MODULE_NAME: &CStr = ansi_str!("api-ms-win-core-synch-l1-2-0");
-        const WAIT_ON_ADDRESS: &CStr = ansi_str!("WaitOnAddress");
-        const WAKE_BY_ADDRESS_SINGLE: &CStr = ansi_str!("WakeByAddressSingle");
+        const MODULE_NAME: &CStr = c"api-ms-win-core-synch-l1-2-0";
+        const WAIT_ON_ADDRESS: &CStr = c"WaitOnAddress";
+        const WAKE_BY_ADDRESS_SINGLE: &CStr = c"WakeByAddressSingle";
 
         // Try loading the library and all the required functions.
         // If any step fails, then they all fail.

library/std/src/sys/windows/mod.rs

@@ -1,6 +1,6 @@
 #![allow(missing_docs, nonstandard_style)]
 
-use crate::ffi::{CStr, OsStr, OsString};
+use crate::ffi::{OsStr, OsString};
 use crate::io::ErrorKind;
 use crate::mem::MaybeUninit;
 use crate::os::windows::ffi::{OsStrExt, OsStringExt};
@@ -51,7 +51,7 @@ pub unsafe fn init(_argc: isize, _argv: *const *const u8, _sigpipe: u8) {
 
     // Normally, `thread::spawn` will call `Thread::set_name` but since this thread already
     // exists, we have to call it ourselves.
-    thread::Thread::set_name(&CStr::from_bytes_with_nul_unchecked(b"main\0"));
+    thread::Thread::set_name(&c"main");
 }
 
 // SAFETY: must be called only once during runtime cleanup.

src/tools/tidy/src/deps.rs

@@ -132,7 +132,6 @@ const PERMITTED_RUSTC_DEPENDENCIES: &[&str] = &[
     "crossbeam-epoch",
     "crossbeam-utils",
     "crypto-common",
-    "cstr",
     "datafrog",
     "derive_more",
     "digest",