Auto merge of #131958 - Zalathar:rollup-gkuk3n1, r=Zalathar

Rollup of 4 pull requests

Successful merges:

 - #131876 (compiler: Use LLVM's Comdat support)
 - #131941 (compiletest: disambiguate html-tidy from rust tidy tool)
 - #131942 (compiler: Adopt rust-analyzer impls for `LayoutCalculatorError`)
 - #131945 (rustdoc: Clean up footnote handling)

r? `@ghost`
`@rustbot` modify labels: rollup

2 files changed, 16 insertions, 9 deletions

diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 661debbb9f1..d0034de06c7 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -646,6 +646,7 @@ unsafe extern "C" {
     pub type Attribute;
     pub type Metadata;
     pub type BasicBlock;
+    pub type Comdat;
 }
 #[repr(C)]
 pub struct Builder<'a>(InvariantOpaque<'a>);
@@ -1490,6 +1491,9 @@ unsafe extern "C" {
     pub fn LLVMSetUnnamedAddress(Global: &Value, UnnamedAddr: UnnamedAddr);
 
     pub fn LLVMIsAConstantInt(value_ref: &Value) -> Option<&ConstantInt>;
+
+    pub fn LLVMGetOrInsertComdat(M: &Module, Name: *const c_char) -> &Comdat;
+    pub fn LLVMSetComdat(V: &Value, C: &Comdat);
 }
 
 #[link(name = "llvm-wrapper", kind = "static")]
@@ -2320,7 +2324,6 @@ unsafe extern "C" {
 
     pub fn LLVMRustPositionBuilderAtStart<'a>(B: &Builder<'a>, BB: &'a BasicBlock);
 
-    pub fn LLVMRustSetComdat<'a>(M: &'a Module, V: &'a Value, Name: *const c_char, NameLen: size_t);
     pub fn LLVMRustSetModulePICLevel(M: &Module);
     pub fn LLVMRustSetModulePIELevel(M: &Module);
     pub fn LLVMRustSetModuleCodeModel(M: &Module, Model: CodeModel);
diff --git a/compiler/rustc_codegen_llvm/src/llvm/mod.rs b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
index d0db350a149..b306396e15a 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
@@ -178,10 +178,10 @@ pub fn SetFunctionCallConv(fn_: &Value, cc: CallConv) {
 // function.
 // For more details on COMDAT sections see e.g., https://www.airs.com/blog/archives/52
 pub fn SetUniqueComdat(llmod: &Module, val: &Value) {
-    unsafe {
-        let name = get_value_name(val);
-        LLVMRustSetComdat(llmod, val, name.as_ptr().cast(), name.len());
-    }
+    let name_buf = get_value_name(val).to_vec();
+    let name =
+        CString::from_vec_with_nul(name_buf).or_else(|buf| CString::new(buf.into_bytes())).unwrap();
+    set_comdat(llmod, val, &name);
 }
 
 pub fn SetUnnamedAddress(global: &Value, unnamed: UnnamedAddr) {
@@ -217,8 +217,7 @@ pub fn set_section(llglobal: &Value, section_name: &str) {
     }
 }
 
-pub fn add_global<'a>(llmod: &'a Module, ty: &'a Type, name: &str) -> &'a Value {
-    let name_cstr = CString::new(name).expect("unexpected CString error");
+pub fn add_global<'a>(llmod: &'a Module, ty: &'a Type, name_cstr: &CStr) -> &'a Value {
     unsafe { LLVMAddGlobal(llmod, ty, name_cstr.as_ptr()) }
 }
 
@@ -252,9 +251,14 @@ pub fn set_alignment(llglobal: &Value, align: Align) {
     }
 }
 
-pub fn set_comdat(llmod: &Module, llglobal: &Value, name: &str) {
+/// Get the `name`d comdat from `llmod` and assign it to `llglobal`.
+///
+/// Inserts the comdat into `llmod` if it does not exist.
+/// It is an error to call this if the target does not support comdat.
+pub fn set_comdat(llmod: &Module, llglobal: &Value, name: &CStr) {
     unsafe {
-        LLVMRustSetComdat(llmod, llglobal, name.as_ptr().cast(), name.len());
+        let comdat = LLVMGetOrInsertComdat(llmod, name.as_ptr());
+        LLVMSetComdat(llglobal, comdat);
     }
 }