Rollup merge of #82057 - upsuper-forks:cstr, r=davidtwco,wesleywiser

Replace const_cstr with cstr crate

This PR replaces the `const_cstr` macro inside `rustc_data_structures` with `cstr` macro from [cstr](https://crates.io/crates/cstr) crate.

The two macros basically serve the same purpose, which is to generate `&'static CStr` from a string literal. `cstr` is better because it validates the literal at compile time, while the existing `const_cstr` does it at runtime when `debug_assertions` is enabled. In addition, the value `cstr` generates can be used in constant context (which is seemingly not needed anywhere currently, though).

Cargo.lock

@@ -904,6 +904,16 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[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 = "ctor"
 version = "0.1.15"
@@ -3698,6 +3708,7 @@ name = "rustc_codegen_llvm"
 version = "0.0.0"
 dependencies = [
  "bitflags",
+ "cstr",
  "libc",
  "measureme",
  "rustc-demangle",

compiler/rustc_codegen_llvm/Cargo.toml

@@ -10,6 +10,7 @@ doctest = false
 
 [dependencies]
 bitflags = "1.0"
+cstr = "0.2"
 libc = "0.2"
 measureme = "9.0.0"
 snap = "1"

compiler/rustc_codegen_llvm/src/abi.rs

@@ -554,7 +554,7 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                 llvm::AddCallSiteAttrString(
                     callsite,
                     llvm::AttributePlace::Function,
-                    rustc_data_structures::const_cstr!("cmse_nonsecure_call"),
+                    cstr::cstr!("cmse_nonsecure_call"),
                 );
             }
         }

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -2,8 +2,8 @@
 
 use std::ffi::CString;
 
+use cstr::cstr;
 use rustc_codegen_ssa::traits::*;
-use rustc_data_structures::const_cstr;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_hir::def_id::DefId;
@@ -75,8 +75,8 @@ pub fn set_frame_pointer_elimination(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value)
         llvm::AddFunctionAttrStringValue(
             llfn,
             llvm::AttributePlace::Function,
-            const_cstr!("frame-pointer"),
+            cstr!("frame-pointer"),
-            const_cstr!("all"),
+            cstr!("all"),
         );
     }
 }
@@ -95,7 +95,7 @@ fn set_instrument_function(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
         llvm::AddFunctionAttrStringValue(
             llfn,
             llvm::AttributePlace::Function,
-            const_cstr!("instrument-function-entry-inlined"),
+            cstr!("instrument-function-entry-inlined"),
             &mcount_name,
         );
     }
@@ -129,16 +129,16 @@ fn set_probestack(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
         StackProbeType::None => None,
         // Request LLVM to generate the probes inline. If the given LLVM version does not support
         // this, no probe is generated at all (even if the attribute is specified).
-        StackProbeType::Inline => Some(const_cstr!("inline-asm")),
+        StackProbeType::Inline => Some(cstr!("inline-asm")),
         // Flag our internal `__rust_probestack` function as the stack probe symbol.
         // This is defined in the `compiler-builtins` crate for each architecture.
-        StackProbeType::Call => Some(const_cstr!("__rust_probestack")),
+        StackProbeType::Call => Some(cstr!("__rust_probestack")),
         // Pick from the two above based on the LLVM version.
         StackProbeType::InlineOrCall { min_llvm_version_for_inline } => {
             if llvm_util::get_version() < min_llvm_version_for_inline {
-                Some(const_cstr!("__rust_probestack"))
+                Some(cstr!("__rust_probestack"))
             } else {
-                Some(const_cstr!("inline-asm"))
+                Some(cstr!("inline-asm"))
             }
         }
     };
@@ -146,7 +146,7 @@ fn set_probestack(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
         llvm::AddFunctionAttrStringValue(
             llfn,
             llvm::AttributePlace::Function,
-            const_cstr!("probe-stack"),
+            cstr!("probe-stack"),
             attr_value,
         );
     }
@@ -169,7 +169,7 @@ pub fn apply_target_cpu_attr(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
     llvm::AddFunctionAttrStringValue(
         llfn,
         llvm::AttributePlace::Function,
-        const_cstr!("target-cpu"),
+        cstr!("target-cpu"),
         target_cpu.as_c_str(),
     );
 }
@@ -180,7 +180,7 @@ pub fn apply_tune_cpu_attr(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
         llvm::AddFunctionAttrStringValue(
             llfn,
             llvm::AttributePlace::Function,
-            const_cstr!("tune-cpu"),
+            cstr!("tune-cpu"),
             tune_cpu.as_c_str(),
         );
     }
@@ -289,7 +289,7 @@ pub fn from_fn_attrs(cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value, instance: ty::
         Attribute::NoAlias.apply_llfn(llvm::AttributePlace::ReturnValue, llfn);
     }
     if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY) {
-        llvm::AddFunctionAttrString(llfn, Function, const_cstr!("cmse_nonsecure_entry"));
+        llvm::AddFunctionAttrString(llfn, Function, cstr!("cmse_nonsecure_entry"));
     }
     sanitize(cx, codegen_fn_attrs.no_sanitize, llfn);
 
@@ -319,7 +319,7 @@ pub fn from_fn_attrs(cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value, instance: ty::
         llvm::AddFunctionAttrStringValue(
             llfn,
             llvm::AttributePlace::Function,
-            const_cstr!("target-features"),
+            cstr!("target-features"),
             &val,
         );
     }
@@ -332,7 +332,7 @@ pub fn from_fn_attrs(cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value, instance: ty::
             llvm::AddFunctionAttrStringValue(
                 llfn,
                 llvm::AttributePlace::Function,
-                const_cstr!("wasm-import-module"),
+                cstr!("wasm-import-module"),
                 &module,
             );
 
@@ -342,7 +342,7 @@ pub fn from_fn_attrs(cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value, instance: ty::
             llvm::AddFunctionAttrStringValue(
                 llfn,
                 llvm::AttributePlace::Function,
-                const_cstr!("wasm-import-name"),
+                cstr!("wasm-import-name"),
                 &name,
             );
         }

compiler/rustc_codegen_llvm/src/builder.rs

@@ -5,13 +5,13 @@ use crate::llvm::{AtomicOrdering, AtomicRmwBinOp, SynchronizationScope};
 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, TypeKind};
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
 use rustc_codegen_ssa::mir::place::PlaceRef;
 use rustc_codegen_ssa::traits::*;
 use rustc_codegen_ssa::MemFlags;
-use rustc_data_structures::const_cstr;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::layout::TyAndLayout;
@@ -979,7 +979,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     }
 
     fn cleanup_pad(&mut self, parent: Option<&'ll Value>, args: &[&'ll Value]) -> Funclet<'ll> {
-        let name = const_cstr!("cleanuppad");
+        let name = cstr!("cleanuppad");
         let ret = unsafe {
             llvm::LLVMRustBuildCleanupPad(
                 self.llbuilder,
@@ -1003,7 +1003,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     }
 
     fn catch_pad(&mut self, parent: &'ll Value, args: &[&'ll Value]) -> Funclet<'ll> {
-        let name = const_cstr!("catchpad");
+        let name = cstr!("catchpad");
         let ret = unsafe {
             llvm::LLVMRustBuildCatchPad(
                 self.llbuilder,
@@ -1022,7 +1022,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         unwind: Option<&'ll BasicBlock>,
         num_handlers: usize,
     ) -> &'ll Value {
-        let name = const_cstr!("catchswitch");
+        let name = cstr!("catchswitch");
         let ret = unsafe {
             llvm::LLVMRustBuildCatchSwitch(
                 self.llbuilder,

compiler/rustc_codegen_llvm/src/consts.rs

@@ -5,9 +5,9 @@ use crate::llvm::{self, True};
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
+use cstr::cstr;
 use libc::c_uint;
 use rustc_codegen_ssa::traits::*;
-use rustc_data_structures::const_cstr;
 use rustc_hir::def_id::DefId;
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc_middle::mir::interpret::{
@@ -419,9 +419,9 @@ impl StaticMethods for CodegenCx<'ll, 'tcx> {
                             .all(|&byte| byte == 0);
 
                     let sect_name = if all_bytes_are_zero {
-                        const_cstr!("__DATA,__thread_bss")
+                        cstr!("__DATA,__thread_bss")
                     } else {
-                        const_cstr!("__DATA,__thread_data")
+                        cstr!("__DATA,__thread_data")
                     };
                     llvm::LLVMSetSection(g, sect_name.as_ptr());
                 }

compiler/rustc_codegen_llvm/src/context.rs

@@ -7,10 +7,10 @@ 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;
-use rustc_data_structures::const_cstr;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_middle::bug;
@@ -414,8 +414,8 @@ impl MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     }
 
     fn create_used_variable(&self) {
-        let name = const_cstr!("llvm.used");
+        let name = cstr!("llvm.used");
-        let section = const_cstr!("llvm.metadata");
+        let section = cstr!("llvm.metadata");
         let array =
             self.const_array(&self.type_ptr_to(self.type_i8()), &*self.used_statics.borrow());
 

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -18,8 +18,8 @@ use crate::llvm::debuginfo::{
 };
 use crate::value::Value;
 
+use cstr::cstr;
 use rustc_codegen_ssa::traits::*;
-use rustc_data_structures::const_cstr;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
@@ -1075,7 +1075,7 @@ pub fn compile_unit_metadata(
                 gcov_cu_info.len() as c_uint,
             );
 
-            let llvm_gcov_ident = const_cstr!("llvm.gcov");
+            let llvm_gcov_ident = cstr!("llvm.gcov");
             llvm::LLVMAddNamedMetadataOperand(
                 debug_context.llmod,
                 llvm_gcov_ident.as_ptr(),
@@ -1093,7 +1093,7 @@ pub fn compile_unit_metadata(
             );
             llvm::LLVMAddNamedMetadataOperand(
                 debug_context.llmod,
-                const_cstr!("llvm.ident").as_ptr(),
+                cstr!("llvm.ident").as_ptr(),
                 llvm::LLVMMDNodeInContext(debug_context.llcontext, &name_metadata, 1),
             );
         }

compiler/rustc_data_structures/src/const_cstr.rs

@@ -1,30 +0,0 @@
-/// This macro creates a zero-overhead &CStr by adding a NUL terminator to
-/// the string literal passed into it at compile-time. Use it like:
-///
-/// ```
-///     let some_const_cstr = const_cstr!("abc");
-/// ```
-///
-/// The above is roughly equivalent to:
-///
-/// ```
-///     let some_const_cstr = CStr::from_bytes_with_nul(b"abc\0").unwrap()
-/// ```
-///
-/// Note that macro only checks the string literal for internal NULs if
-/// debug-assertions are enabled in order to avoid runtime overhead in release
-/// builds.
-#[macro_export]
-macro_rules! const_cstr {
-    ($s:expr) => {{
-        use std::ffi::CStr;
-
-        let str_plus_nul = concat!($s, "\0");
-
-        if cfg!(debug_assertions) {
-            CStr::from_bytes_with_nul(str_plus_nul.as_bytes()).unwrap()
-        } else {
-            unsafe { CStr::from_bytes_with_nul_unchecked(str_plus_nul.as_bytes()) }
-        }
-    }};
-}

compiler/rustc_data_structures/src/lib.rs

@@ -69,7 +69,6 @@ pub mod base_n;
 pub mod binary_search_util;
 pub mod box_region;
 pub mod captures;
-pub mod const_cstr;
 pub mod flock;
 pub mod functor;
 pub mod fx;

src/tools/tidy/src/deps.rs

@@ -85,6 +85,7 @@ const PERMITTED_DEPENDENCIES: &[&str] = &[
     "crossbeam-epoch",
     "crossbeam-queue",
     "crossbeam-utils",
+    "cstr",
     "datafrog",
     "difference",
     "digest",