cg_llvm: Avoid all remaining uses of as_c_char_ptr

compiler/rustc_codegen_llvm/src/common.rs

@@ -2,7 +2,7 @@
 
 use std::borrow::Borrow;
 
-use libc::{c_char, c_uint};
+use libc::c_uint;
 use rustc_abi::Primitive::Pointer;
 use rustc_abi::{self as abi, ExternAbi, HasDataLayout as _};
 use rustc_ast::Mutability;
@@ -511,21 +511,3 @@ pub(crate) fn get_dllimport<'tcx>(
     tcx.native_library(id)
         .and_then(|lib| lib.dll_imports.iter().find(|di| di.name.as_str() == name))
 }
-
-/// Extension trait for explicit casts to `*const c_char`.
-pub(crate) trait AsCCharPtr {
-    /// Equivalent to `self.as_ptr().cast()`, but only casts to `*const c_char`.
-    fn as_c_char_ptr(&self) -> *const c_char;
-}
-
-impl AsCCharPtr for str {
-    fn as_c_char_ptr(&self) -> *const c_char {
-        self.as_ptr().cast()
-    }
-}
-
-impl AsCCharPtr for [u8] {
-    fn as_c_char_ptr(&self) -> *const c_char {
-        self.as_ptr().cast()
-    }
-}

compiler/rustc_codegen_llvm/src/llvm/enzyme_ffi.rs

@@ -1,6 +1,6 @@
 #![expect(dead_code)]
 
-use libc::{c_char, c_uint};
+use libc::{c_char, c_uchar, c_uint};
 
 use super::MetadataKindId;
 use super::ffi::{AttributeKind, BasicBlock, Context, Metadata, Module, Type, Value};
@@ -47,10 +47,14 @@ unsafe extern "C" {
     pub(crate) fn LLVMRustGetArrayNumElements(Ty: &Type) -> u64;
     pub(crate) fn LLVMRustHasFnAttribute(
         F: &Value,
-        Name: *const c_char,
+        Name: *const c_uchar, // See "PTR_LEN_STR".
         NameLen: libc::size_t,
     ) -> bool;
-    pub(crate) fn LLVMRustRemoveFnAttribute(F: &Value, Name: *const c_char, NameLen: libc::size_t);
+    pub(crate) fn LLVMRustRemoveFnAttribute(
+        F: &Value,
+        Name: *const c_uchar, // See "PTR_LEN_STR".
+        NameLen: libc::size_t,
+    );
     pub(crate) fn LLVMGetFirstFunction(M: &Module) -> Option<&Value>;
     pub(crate) fn LLVMGetNextFunction(Fn: &Value) -> Option<&Value>;
     pub(crate) fn LLVMRustRemoveEnumAttributeAtIndex(

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -982,7 +982,11 @@ unsafe extern "C" {
     // Operations on all values
     pub(crate) fn LLVMTypeOf(Val: &Value) -> &Type;
     pub(crate) fn LLVMGetValueName2(Val: &Value, Length: *mut size_t) -> *const c_char;
-    pub(crate) fn LLVMSetValueName2(Val: &Value, Name: *const c_char, NameLen: size_t);
+    pub(crate) fn LLVMSetValueName2(
+        Val: &Value,
+        Name: *const c_uchar, // See "PTR_LEN_STR".
+        NameLen: size_t,
+    );
     pub(crate) fn LLVMReplaceAllUsesWith<'a>(OldVal: &'a Value, NewVal: &'a Value);
     pub(crate) safe fn LLVMGetMetadata<'a>(
         Val: &'a Value,
@@ -1117,9 +1121,9 @@ unsafe extern "C" {
     // Operations on attributes
     pub(crate) fn LLVMCreateStringAttribute(
         C: &Context,
-        Name: *const c_char,
+        Name: *const c_uchar, // See "PTR_LEN_STR".
         NameLen: c_uint,
-        Value: *const c_char,
+        Value: *const c_uchar, // See "PTR_LEN_STR".
         ValueLen: c_uint,
     ) -> &Attribute;
 
@@ -1139,7 +1143,10 @@ unsafe extern "C" {
     ) -> &'a Value;
 
     // Operations about llvm intrinsics
-    pub(crate) fn LLVMLookupIntrinsicID(Name: *const c_char, NameLen: size_t) -> c_uint;
+    pub(crate) fn LLVMLookupIntrinsicID(
+        Name: *const c_uchar, // See "PTR_LEN_STR".
+        NameLen: size_t,
+    ) -> c_uint;
     pub(crate) fn LLVMIntrinsicIsOverloaded(ID: NonZero<c_uint>) -> Bool;
     pub(crate) fn LLVMGetIntrinsicDeclaration<'a>(
         Mod: &'a Module,
@@ -1675,7 +1682,7 @@ unsafe extern "C" {
     pub(crate) fn LLVMSetComdat(V: &Value, C: &Comdat);
 
     pub(crate) fn LLVMCreateOperandBundle(
-        Tag: *const c_char,
+        Tag: *const c_uchar, // See "PTR_LEN_STR".
         TagLen: size_t,
         Args: *const &'_ Value,
         NumArgs: c_uint,
@@ -2186,17 +2193,17 @@ unsafe extern "C" {
     pub(crate) fn LLVMRustAddModuleFlagU32(
         M: &Module,
         MergeBehavior: ModuleFlagMergeBehavior,
-        Name: *const c_char,
+        Name: *const c_uchar, // See "PTR_LEN_STR".
         NameLen: size_t,
         Value: u32,
     );
 
     pub(crate) fn LLVMRustAddModuleFlagString(
         M: &Module,
         MergeBehavior: ModuleFlagMergeBehavior,
-        Name: *const c_char,
+        Name: *const c_uchar, // See "PTR_LEN_STR".
         NameLen: size_t,
-        Value: *const c_char,
+        Value: *const c_uchar, // See "PTR_LEN_STR".
         ValueLen: size_t,
     );
 

compiler/rustc_codegen_llvm/src/llvm/mod.rs

@@ -14,7 +14,6 @@ pub(crate) use self::CodeGenOptSize::*;
 pub(crate) use self::conversions::*;
 pub(crate) use self::ffi::*;
 pub(crate) use self::metadata_kind::*;
-use crate::common::AsCCharPtr;
 
 mod conversions;
 pub(crate) mod diagnostic;
@@ -46,11 +45,11 @@ pub(crate) fn AddFunctionAttributes<'ll>(
 }
 
 pub(crate) fn HasStringAttribute<'ll>(llfn: &'ll Value, name: &str) -> bool {
-    unsafe { LLVMRustHasFnAttribute(llfn, name.as_c_char_ptr(), name.len()) }
+    unsafe { LLVMRustHasFnAttribute(llfn, name.as_ptr(), name.len()) }
 }
 
 pub(crate) fn RemoveStringAttrFromFn<'ll>(llfn: &'ll Value, name: &str) {
-    unsafe { LLVMRustRemoveFnAttribute(llfn, name.as_c_char_ptr(), name.len()) }
+    unsafe { LLVMRustRemoveFnAttribute(llfn, name.as_ptr(), name.len()) }
 }
 
 pub(crate) fn AddCallSiteAttributes<'ll>(
@@ -71,9 +70,9 @@ pub(crate) fn CreateAttrStringValue<'ll>(
     unsafe {
         LLVMCreateStringAttribute(
             llcx,
-            attr.as_c_char_ptr(),
+            attr.as_ptr(),
             attr.len().try_into().unwrap(),
-            value.as_c_char_ptr(),
+            value.as_ptr(),
             value.len().try_into().unwrap(),
         )
     }
@@ -83,13 +82,15 @@ pub(crate) fn CreateAttrStringValueFromCStr<'ll>(
     attr: &std::ffi::CStr,
     value: &std::ffi::CStr,
 ) -> &'ll Attribute {
+    let attr = attr.to_bytes();
+    let value = value.to_bytes();
     unsafe {
         LLVMCreateStringAttribute(
             llcx,
-            (*attr).as_ptr(),
-            (*attr).to_bytes().len() as c_uint,
-            (*value).as_ptr(),
-            (*value).to_bytes().len() as c_uint,
+            attr.as_ptr(),
+            attr.len() as c_uint,
+            value.as_ptr(),
+            value.len() as c_uint,
         )
     }
 }
@@ -98,7 +99,7 @@ pub(crate) fn CreateAttrString<'ll>(llcx: &'ll Context, attr: &str) -> &'ll Attr
     unsafe {
         LLVMCreateStringAttribute(
             llcx,
-            attr.as_c_char_ptr(),
+            attr.as_ptr(),
             attr.len().try_into().unwrap(),
             std::ptr::null(),
             0,
@@ -340,7 +341,7 @@ pub(crate) struct Intrinsic {
 
 impl Intrinsic {
     pub(crate) fn lookup(name: &[u8]) -> Option<Self> {
-        let id = unsafe { LLVMLookupIntrinsicID(name.as_c_char_ptr(), name.len()) };
+        let id = unsafe { LLVMLookupIntrinsicID(name.as_ptr(), name.len()) };
         NonZero::new(id).map(|id| Self { id })
     }
 
@@ -365,10 +366,7 @@ impl Intrinsic {
 
 /// Safe wrapper for `LLVMSetValueName2` from a byte slice
 pub(crate) fn set_value_name(value: &Value, name: &[u8]) {
-    unsafe {
-        let data = name.as_c_char_ptr();
-        LLVMSetValueName2(value, data, name.len());
-    }
+    unsafe { LLVMSetValueName2(value, name.as_ptr(), name.len()) };
 }
 
 pub(crate) fn build_string(f: impl FnOnce(&RustString)) -> Result<String, FromUtf8Error> {
@@ -408,12 +406,7 @@ pub(crate) struct OperandBundleBox<'a> {
 impl<'a> OperandBundleBox<'a> {
     pub(crate) fn new(name: &str, vals: &[&'a Value]) -> Self {
         let raw = unsafe {
-            LLVMCreateOperandBundle(
-                name.as_c_char_ptr(),
-                name.len(),
-                vals.as_ptr(),
-                vals.len() as c_uint,
-            )
+            LLVMCreateOperandBundle(name.as_ptr(), name.len(), vals.as_ptr(), vals.len() as c_uint)
         };
         Self { raw: ptr::NonNull::new(raw).unwrap() }
     }
@@ -444,7 +437,7 @@ pub(crate) fn add_module_flag_u32(
     value: u32,
 ) {
     unsafe {
-        LLVMRustAddModuleFlagU32(module, merge_behavior, key.as_c_char_ptr(), key.len(), value);
+        LLVMRustAddModuleFlagU32(module, merge_behavior, key.as_ptr(), key.len(), value);
     }
 }
 
@@ -458,9 +451,9 @@ pub(crate) fn add_module_flag_str(
         LLVMRustAddModuleFlagString(
             module,
             merge_behavior,
-            key.as_c_char_ptr(),
+            key.as_ptr(),
             key.len(),
-            value.as_c_char_ptr(),
+            value.as_ptr(),
             value.len(),
         );
     }