Rollup merge of #132340 - Zalathar:set-section, r=compiler-errors

cg_llvm: Consistently use safe wrapper function `set_section`

Follow-up to #131962 and https://github.com/rust-lang/rust/pull/132260#discussion_r1821626260.

To avoid too much scope creep, I've deliberately kept the changes to `LLVMRustGetSliceFromObjectDataByName` as minimal as possible.

2 files changed, 9 insertions, 10 deletions

diff --git a/compiler/rustc_codegen_llvm/src/back/lto.rs b/compiler/rustc_codegen_llvm/src/back/lto.rs
index 02149e176ea..48beb9be2b2 100644
--- a/compiler/rustc_codegen_llvm/src/back/lto.rs
+++ b/compiler/rustc_codegen_llvm/src/back/lto.rs
@@ -165,13 +165,14 @@ fn get_bitcode_slice_from_object_data<'a>(
     // We drop the "__LLVM," prefix here because on Apple platforms there's a notion of "segment
     // name" which in the public API for sections gets treated as part of the section name, but
     // internally in MachOObjectFile.cpp gets treated separately.
-    let section_name = bitcode_section_name(cgcx).trim_start_matches("__LLVM,");
+    let section_name = bitcode_section_name(cgcx).to_str().unwrap().trim_start_matches("__LLVM,");
     let mut len = 0;
     let data = unsafe {
         llvm::LLVMRustGetSliceFromObjectDataByName(
             obj.as_ptr(),
             obj.len(),
             section_name.as_ptr(),
+            section_name.len(),
             &mut len,
         )
     };
diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs
index e68ba96f14f..bfa9e8b82a0 100644
--- a/compiler/rustc_codegen_llvm/src/back/write.rs
+++ b/compiler/rustc_codegen_llvm/src/back/write.rs
@@ -1,4 +1,4 @@
-use std::ffi::CString;
+use std::ffi::{CStr, CString};
 use std::io::{self, Write};
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
@@ -958,14 +958,13 @@ 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 {
+pub(crate) fn bitcode_section_name(cgcx: &CodegenContext<LlvmCodegenBackend>) -> &'static CStr {
     if target_is_apple(cgcx) {
-        "__LLVM,__bitcode\0"
+        c"__LLVM,__bitcode"
     } else if target_is_aix(cgcx) {
-        ".ipa\0"
+        c".ipa"
     } else {
-        ".llvmbc\0"
+        c".llvmbc"
     }
 }
 
@@ -1042,8 +1041,7 @@ unsafe fn embed_bitcode(
             );
             llvm::LLVMSetInitializer(llglobal, llconst);
 
-            let section = bitcode_section_name(cgcx);
-            llvm::LLVMSetSection(llglobal, section.as_c_char_ptr());
+            llvm::set_section(llglobal, bitcode_section_name(cgcx));
             llvm::set_linkage(llglobal, llvm::Linkage::PrivateLinkage);
             llvm::LLVMSetGlobalConstant(llglobal, llvm::True);
 
@@ -1061,7 +1059,7 @@ unsafe fn embed_bitcode(
             } else {
                 c".llvmcmd"
             };
-            llvm::LLVMSetSection(llglobal, section.as_ptr());
+            llvm::set_section(llglobal, section);
             llvm::set_linkage(llglobal, llvm::Linkage::PrivateLinkage);
         } else {
             // We need custom section flags, so emit module-level inline assembly.