cg_llvm: Avoid some explicit casts to *const c_char

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -312,11 +312,7 @@ fn fat_lto(
             let data = bc_decoded.data();
 
             unsafe {
-                if !llvm::LLVMRustLinkerAdd(
-                    linker,
-                    data.as_ptr() as *const libc::c_char,
-                    data.len(),
-                ) {
+                if !llvm::LLVMRustLinkerAdd(linker, data.as_ptr(), data.len()) {
                     llvm::LLVMRustLinkerFree(linker);
                     write::llvm_err(dcx, LlvmError::LoadBitcode { name })
                 }
@@ -327,10 +323,9 @@ fn fat_lto(
 
         // Internalize everything below threshold to help strip out more modules and such.
         unsafe {
-            let ptr = symbols_below_threshold.as_ptr();
             llvm::LLVMRustRunRestrictionPass(
                 llmod,
-                ptr as *const *const libc::c_char,
+                symbols_below_threshold.as_ptr(),
                 symbols_below_threshold.len() as libc::size_t,
             );
         }

compiler/rustc_codegen_llvm/src/common.rs

@@ -470,20 +470,14 @@ pub(crate) fn val_ty(v: &Value) -> &Type {
 }
 
 pub(crate) fn bytes_in_context<'ll>(llcx: &'ll llvm::Context, bytes: &[u8]) -> &'ll Value {
-    unsafe {
-        let ptr = bytes.as_ptr() as *const c_char;
-        llvm::LLVMConstStringInContext2(llcx, ptr, bytes.len(), TRUE)
-    }
+    unsafe { llvm::LLVMConstStringInContext2(llcx, bytes.as_ptr(), bytes.len(), TRUE) }
 }
 
 pub(crate) fn null_terminate_bytes_in_context<'ll>(
     llcx: &'ll llvm::Context,
     bytes: &[u8],
 ) -> &'ll Value {
-    unsafe {
-        let ptr = bytes.as_ptr() as *const c_char;
-        llvm::LLVMConstStringInContext2(llcx, ptr, bytes.len(), FALSE)
-    }
+    unsafe { llvm::LLVMConstStringInContext2(llcx, bytes.as_ptr(), bytes.len(), FALSE) }
 }
 
 pub(crate) fn named_struct<'ll>(ty: &'ll Type, elts: &[&'ll Value]) -> &'ll Value {

compiler/rustc_codegen_llvm/src/context.rs

@@ -1,6 +1,6 @@
 use std::borrow::{Borrow, Cow};
 use std::cell::{Cell, RefCell};
-use std::ffi::{CStr, c_char, c_uint};
+use std::ffi::{CStr, c_uint};
 use std::marker::PhantomData;
 use std::ops::{Deref, DerefMut};
 use std::str;
@@ -911,19 +911,11 @@ impl<'ll, CX: Borrow<SCx<'ll>>> GenericCx<'ll, CX> {
     }
 
     pub(crate) fn get_md_kind_id(&self, name: &str) -> llvm::MetadataKindId {
-        unsafe {
-            llvm::LLVMGetMDKindIDInContext(
-                self.llcx(),
-                name.as_ptr() as *const c_char,
-                name.len() as c_uint,
-            )
-        }
+        unsafe { llvm::LLVMGetMDKindIDInContext(self.llcx(), name.as_ptr(), name.len() as c_uint) }
     }
 
     pub(crate) fn create_metadata(&self, name: &[u8]) -> &'ll Metadata {
-        unsafe {
-            llvm::LLVMMDStringInContext2(self.llcx(), name.as_ptr() as *const c_char, name.len())
-        }
+        unsafe { llvm::LLVMMDStringInContext2(self.llcx(), name.as_ptr(), name.len()) }
     }
 
     pub(crate) fn get_functions(&self) -> Vec<&'ll Value> {

compiler/rustc_codegen_llvm/src/llvm/enzyme_ffi.rs

@@ -329,10 +329,7 @@ pub(crate) mod Enzyme_AD {
             let c_fun_name = std::ffi::CString::new(fun_name)
                 .unwrap_or_else(|err| bug!("failed to set_print_type_fun: {err}"));
             unsafe {
-                (self.EnzymeSetCLString)(
-                    self.EnzymeFunctionToAnalyze,
-                    c_fun_name.as_ptr() as *const c_char,
-                );
+                (self.EnzymeSetCLString)(self.EnzymeFunctionToAnalyze, c_fun_name.as_ptr());
             }
         }
 

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -890,7 +890,7 @@ unsafe extern "C" {
     pub(crate) fn LLVMContextSetDiscardValueNames(C: &Context, Discard: Bool);
     pub(crate) fn LLVMGetMDKindIDInContext(
         C: &Context,
-        Name: *const c_char,
+        Name: *const c_uchar, // See "PTR_LEN_STR".
         SLen: c_uint,
     ) -> MetadataKindId;
 
@@ -1009,7 +1009,7 @@ unsafe extern "C" {
     // Operations on metadata
     pub(crate) fn LLVMMDStringInContext2(
         C: &Context,
-        Str: *const c_char,
+        Str: *const c_uchar, // See "PTR_LEN_STR".
         SLen: size_t,
     ) -> &Metadata;
     pub(crate) fn LLVMMDNodeInContext2<'a>(
@@ -1042,7 +1042,7 @@ unsafe extern "C" {
     pub(crate) fn LLVMArrayType2(ElementType: &Type, ElementCount: u64) -> &Type;
     pub(crate) fn LLVMConstStringInContext2(
         C: &Context,
-        Str: *const c_char,
+        Str: *const c_uchar, // See "PTR_LEN_STR".
         Length: size_t,
         DontNullTerminate: Bool,
     ) -> &Value;
@@ -2561,7 +2561,7 @@ unsafe extern "C" {
     pub(crate) fn LLVMRustLinkerNew(M: &Module) -> &mut Linker<'_>;
     pub(crate) fn LLVMRustLinkerAdd(
         linker: &Linker<'_>,
-        bytecode: *const c_char,
+        bytecode: *const c_uchar, // See "PTR_LEN_STR".
         bytecode_len: usize,
     ) -> bool;
     pub(crate) fn LLVMRustLinkerFree<'a>(linker: &'a mut Linker<'a>);