use c literals in compiler and library

Cargo.lock

@@ -869,16 +869,6 @@ 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 = "3.4.0"
@@ -3585,7 +3575,6 @@ name = "rustc_codegen_llvm"
 version = "0.0.0"
 dependencies = [
  "bitflags 1.3.2",
- "cstr",
  "itertools",
  "libc",
  "measureme",

compiler/rustc_codegen_llvm/Cargo.toml

@@ -9,7 +9,6 @@ test = false
 [dependencies]
 # tidy-alphabetical-start
 bitflags = "1.0"
-cstr = "0.2"
 itertools = "0.11"
 libc = "0.2"
 measureme = "10.0.0"

compiler/rustc_codegen_llvm/src/allocator.rs

@@ -146,7 +146,7 @@ fn create_wrapper_function(
         }
         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

@@ -631,7 +631,7 @@ 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

@@ -916,6 +916,7 @@ fn target_is_aix(cgcx: &CodegenContext<LlvmCodegenBackend>) -> bool {
     cgcx.opts.target_triple.triple().contains("-aix")
 }
 
+//FIXME use c string literals here too
 pub(crate) fn bitcode_section_name(cgcx: &CodegenContext<LlvmCodegenBackend>) -> &'static str {
     if target_is_apple(cgcx) {
         "__LLVM,__bitcode\0"
@@ -994,7 +995,7 @@ 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);
 
@@ -1007,15 +1008,15 @@ 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"
+            c"__LLVM,__cmdline"
         } else if is_aix {
-            ".info\0"
+            c".info"
         } else {
-            ".llvmcmd\0"
+            c".llvmcmd"
         };
         llvm::LLVMSetSection(llglobal, section.as_ptr().cast());
         llvm::LLVMRustSetLinkage(llglobal, llvm::Linkage::PrivateLinkage);

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

@@ -7,7 +7,6 @@ use crate::llvm_util;
 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};
@@ -27,7 +26,6 @@ use rustc_target::abi::{self, call::FnAbi, Align, Size, WrappingRange};
 use rustc_target::spec::{HasTargetSpec, SanitizerSet, Target};
 use smallvec::SmallVec;
 use std::borrow::Cow;
-use std::ffi::CStr;
 use std::iter;
 use std::ops::Deref;
 use std::ptr;
@@ -47,13 +45,10 @@ 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;
@@ -1003,14 +998,13 @@ 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"))
@@ -1024,14 +1018,13 @@ 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"))
@@ -1043,14 +1036,13 @@ 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};
@@ -476,9 +475,9 @@ 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());
                 }
@@ -507,7 +506,7 @@ 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, wants_wasm_eh};
 use rustc_codegen_ssa::errors as ssa_errors;
 use rustc_codegen_ssa::traits::*;
@@ -214,13 +213,13 @@ 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();
+        let avoid_plt = c"RtLibUseGOT".as_ptr().cast();
         llvm::LLVMRustAddModuleFlag(llmod, llvm::LLVMModFlagBehavior::Warning, avoid_plt, 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();
+        let canonical_jump_tables = c"CFI Canonical Jump Tables".as_ptr().cast();
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
@@ -231,7 +230,7 @@ pub unsafe fn create_module<'ll>(
 
     // 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();
+        let enable_split_lto_unit = c"EnableSplitLTOUnit".as_ptr().cast();
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
@@ -242,7 +241,7 @@ pub unsafe fn create_module<'ll>(
 
     // 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();
+        let kcfi = c"kcfi".as_ptr().cast();
         llvm::LLVMRustAddModuleFlag(llmod, llvm::LLVMModFlagBehavior::Override, kcfi, 1);
     }
 
@@ -255,7 +254,7 @@ 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,
                 )
             }
@@ -264,7 +263,7 @@ 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,
                 )
             }
@@ -282,26 +281,26 @@ 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 {
@@ -317,15 +316,15 @@ 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,
         )
     }
@@ -334,7 +333,7 @@ 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,
         );
     }
@@ -344,7 +343,7 @@ pub unsafe fn create_module<'ll>(
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Warning,
-            "ehcontguard\0".as_ptr() as *const _,
+            c"ehcontguard".as_ptr() as *const _,
             1,
         )
     }
@@ -362,7 +361,7 @@ pub unsafe fn create_module<'ll>(
     );
     llvm::LLVMAddNamedMetadataOperand(
         llmod,
-        cstr!("llvm.ident").as_ptr(),
+        c"llvm.ident".as_ptr(),
         llvm::LLVMMDNodeInContext(llcx, &name_metadata, 1),
     );
 
@@ -510,14 +509,13 @@ 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(), 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

@@ -30,14 +30,13 @@ pub fn insert_reference_to_gdb_debug_scripts_section_global(bx: &mut Builder<'_,
 /// Allocates the global variable responsible for the .debug_gdb_scripts binary
 /// section.
 pub fn get_or_insert_gdb_debug_scripts_section_global<'ll>(cx: &CodegenCx<'ll, '_>) -> &'ll Value {
-    let c_section_var_name = "__rustc_debug_gdb_scripts_section__\0";
-    let section_var_name = &c_section_var_name[..c_section_var_name.len() - 1];
+    let c_section_var_name = c"__rustc_debug_gdb_scripts_section__";
+    let section_var_name = c_section_var_name.to_str().unwrap();
 
     let section_var =
         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.
@@ -70,7 +69,7 @@ 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);