11use std:: borrow:: Borrow ;
2- use std:: cmp;
2+ use std:: { cmp, iter } ;
33
44use libc:: c_uint;
55use rustc_abi:: {
@@ -308,8 +308,37 @@ impl<'ll, 'tcx> ArgAbiBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
308308 }
309309}
310310
311+ pub ( crate ) enum FunctionSignature < ' ll > {
312+ /// The signature is obtained directly from LLVM, and **may not match the Rust signature**
313+ Intrinsic ( & ' ll Type ) ,
314+ /// The name starts with `llvm.`, but can't obtain the intrinsic ID. May be invalid or upgradable
315+ MaybeInvalidIntrinsic ( & ' ll Type ) ,
316+ /// Just the Rust signature
317+ Rust ( & ' ll Type ) ,
318+ }
319+
320+ impl < ' ll > FunctionSignature < ' ll > {
321+ pub ( crate ) fn fn_ty ( & self ) -> & ' ll Type {
322+ match self {
323+ FunctionSignature :: Intrinsic ( fn_ty)
324+ | FunctionSignature :: MaybeInvalidIntrinsic ( fn_ty)
325+ | FunctionSignature :: Rust ( fn_ty) => fn_ty,
326+ }
327+ }
328+ }
329+
311330pub ( crate ) trait FnAbiLlvmExt < ' ll , ' tcx > {
312- fn llvm_type ( & self , cx : & CodegenCx < ' ll , ' tcx > ) -> & ' ll Type ;
331+ fn llvm_return_type ( & self , cx : & CodegenCx < ' ll , ' tcx > ) -> & ' ll Type ;
332+ fn llvm_argument_types ( & self , cx : & CodegenCx < ' ll , ' tcx > ) -> Vec < & ' ll Type > ;
333+ fn llvm_type (
334+ & self ,
335+ cx : & CodegenCx < ' ll , ' tcx > ,
336+ name : & [ u8 ] ,
337+ do_verify : bool ,
338+ ) -> FunctionSignature < ' ll > ;
339+ /// **If this function is an LLVM intrinsic** checks if the LLVM signature provided matches with this
340+ fn verify_intrinsic_signature ( & self , cx : & CodegenCx < ' ll , ' tcx > , llvm_ty : & ' ll Type ) -> bool ;
341+
313342 fn ptr_to_llvm_type ( & self , cx : & CodegenCx < ' ll , ' tcx > ) -> & ' ll Type ;
314343 fn llvm_cconv ( & self , cx : & CodegenCx < ' ll , ' tcx > ) -> llvm:: CallConv ;
315344
@@ -322,30 +351,39 @@ pub(crate) trait FnAbiLlvmExt<'ll, 'tcx> {
322351 ) ;
323352
324353 /// Apply attributes to a function call.
325- fn apply_attrs_callsite ( & self , bx : & mut Builder < ' _ , ' ll , ' tcx > , callsite : & ' ll Value ) ;
354+ fn apply_attrs_callsite (
355+ & self ,
356+ bx : & mut Builder < ' _ , ' ll , ' tcx > ,
357+ callsite : & ' ll Value ,
358+ llfn : & ' ll Value ,
359+ ) ;
326360}
327361
328362impl < ' ll , ' tcx > FnAbiLlvmExt < ' ll , ' tcx > for FnAbi < ' tcx , Ty < ' tcx > > {
329- fn llvm_type ( & self , cx : & CodegenCx < ' ll , ' tcx > ) -> & ' ll Type {
363+ fn llvm_return_type ( & self , cx : & CodegenCx < ' ll , ' tcx > ) -> & ' ll Type {
364+ match & self . ret . mode {
365+ PassMode :: Ignore => cx. type_void ( ) ,
366+ PassMode :: Direct ( _) | PassMode :: Pair ( ..) => self . ret . layout . immediate_llvm_type ( cx) ,
367+ PassMode :: Cast { cast, pad_i32 : _ } => cast. llvm_type ( cx) ,
368+ PassMode :: Indirect { .. } => cx. type_void ( ) ,
369+ }
370+ }
371+
372+ fn llvm_argument_types ( & self , cx : & CodegenCx < ' ll , ' tcx > ) -> Vec < & ' ll Type > {
373+ let indirect_return = matches ! ( self . ret. mode, PassMode :: Indirect { .. } ) ;
374+
330375 // Ignore "extra" args from the call site for C variadic functions.
331376 // Only the "fixed" args are part of the LLVM function signature.
332377 let args =
333378 if self . c_variadic { & self . args [ ..self . fixed_count as usize ] } else { & self . args } ;
334379
335380 // This capacity calculation is approximate.
336- let mut llargument_tys = Vec :: with_capacity (
337- self . args . len ( ) + if let PassMode :: Indirect { .. } = self . ret . mode { 1 } else { 0 } ,
338- ) ;
381+ let mut llargument_tys =
382+ Vec :: with_capacity ( args. len ( ) + if indirect_return { 1 } else { 0 } ) ;
339383
340- let llreturn_ty = match & self . ret . mode {
341- PassMode :: Ignore => cx. type_void ( ) ,
342- PassMode :: Direct ( _) | PassMode :: Pair ( ..) => self . ret . layout . immediate_llvm_type ( cx) ,
343- PassMode :: Cast { cast, pad_i32 : _ } => cast. llvm_type ( cx) ,
344- PassMode :: Indirect { .. } => {
345- llargument_tys. push ( cx. type_ptr ( ) ) ;
346- cx. type_void ( )
347- }
348- } ;
384+ if indirect_return {
385+ llargument_tys. push ( cx. type_ptr ( ) ) ;
386+ }
349387
350388 for arg in args {
351389 // Note that the exact number of arguments pushed here is carefully synchronized with
@@ -392,10 +430,72 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
392430 llargument_tys. push ( llarg_ty) ;
393431 }
394432
395- if self . c_variadic {
396- cx. type_variadic_func ( & llargument_tys, llreturn_ty)
433+ llargument_tys
434+ }
435+
436+ fn verify_intrinsic_signature ( & self , cx : & CodegenCx < ' ll , ' tcx > , llvm_fn_ty : & ' ll Type ) -> bool {
437+ let rust_return_ty = self . llvm_return_type ( cx) ;
438+ let rust_argument_tys = self . llvm_argument_types ( cx) ;
439+
440+ let llvm_return_ty = cx. get_return_type ( llvm_fn_ty) ;
441+ let llvm_argument_tys = cx. func_params_types ( llvm_fn_ty) ;
442+ let llvm_is_variadic = cx. func_is_variadic ( llvm_fn_ty) ;
443+
444+ if self . c_variadic != llvm_is_variadic || rust_argument_tys. len ( ) != llvm_argument_tys. len ( )
445+ {
446+ return false ;
447+ }
448+
449+ iter:: once ( ( rust_return_ty, llvm_return_ty) )
450+ . chain ( iter:: zip ( rust_argument_tys, llvm_argument_tys) )
451+ . all ( |( rust_ty, llvm_ty) | rust_ty == llvm_ty)
452+ }
453+
454+ fn llvm_type (
455+ & self ,
456+ cx : & CodegenCx < ' ll , ' tcx > ,
457+ name : & [ u8 ] ,
458+ do_verify : bool ,
459+ ) -> FunctionSignature < ' ll > {
460+ let mut maybe_invalid = false ;
461+
462+ if name. starts_with ( b"llvm." ) {
463+ if let Some ( intrinsic) = llvm:: Intrinsic :: lookup ( name) {
464+ if !intrinsic. is_overloaded ( ) {
465+ // FIXME: also do this for overloaded intrinsics
466+ let llvm_fn_ty = intrinsic. get_type ( cx. llcx , & [ ] ) ;
467+ if do_verify {
468+ if !self . verify_intrinsic_signature ( cx, llvm_fn_ty) {
469+ cx. tcx . dcx ( ) . fatal ( format ! (
470+ "Intrinsic signature mismatch for `{}`: expected signature `{llvm_fn_ty:?}`" ,
471+ str :: from_utf8( name) . unwrap( )
472+ ) ) ;
473+ }
474+ }
475+ return FunctionSignature :: Intrinsic ( llvm_fn_ty) ;
476+ }
477+ } else {
478+ // it's one of 2 cases,
479+ // - either the base name is invalid
480+ // - it has been superseded by something else, so the intrinsic was removed entirely
481+ // to check for upgrades, we need the `llfn`, so we defer it for now
482+ maybe_invalid = true ;
483+ }
484+ }
485+
486+ let return_ty = self . llvm_return_type ( cx) ;
487+ let argument_tys = self . llvm_argument_types ( cx) ;
488+
489+ let fn_ty = if self . c_variadic {
490+ cx. type_variadic_func ( & argument_tys, return_ty)
397491 } else {
398- cx. type_func ( & llargument_tys, llreturn_ty)
492+ cx. type_func ( & argument_tys, return_ty)
493+ } ;
494+
495+ if maybe_invalid {
496+ FunctionSignature :: MaybeInvalidIntrinsic ( fn_ty)
497+ } else {
498+ FunctionSignature :: Rust ( fn_ty)
399499 }
400500 }
401501
@@ -547,7 +647,23 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
547647 }
548648 }
549649
550- fn apply_attrs_callsite ( & self , bx : & mut Builder < ' _ , ' ll , ' tcx > , callsite : & ' ll Value ) {
650+ fn apply_attrs_callsite (
651+ & self ,
652+ bx : & mut Builder < ' _ , ' ll , ' tcx > ,
653+ callsite : & ' ll Value ,
654+ llfn : & ' ll Value ,
655+ ) {
656+ // if we are using the LLVM signature, use the LLVM attributes otherwise it might be problematic
657+ let name = llvm:: get_value_name ( llfn) ;
658+ if name. starts_with ( b"llvm." )
659+ && let Some ( intrinsic) = llvm:: Intrinsic :: lookup ( & name)
660+ {
661+ // FIXME: also do this for overloaded intrinsics
662+ if !intrinsic. is_overloaded ( ) {
663+ return ;
664+ }
665+ }
666+
551667 let mut func_attrs = SmallVec :: < [ _ ; 2 ] > :: new ( ) ;
552668 if self . ret . layout . is_uninhabited ( ) {
553669 func_attrs. push ( llvm:: AttributeKind :: NoReturn . create_attr ( bx. cx . llcx ) ) ;
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