cg_llvm: remove pointee types and pointercast/bitcast-of-ptr

Author: erikdesjardins

compiler/rustc_codegen_llvm/src/abi.rs

@@ -216,9 +216,7 @@ impl<'ll, 'tcx> ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
             // uses it for i16 -> {i8, i8}, but not for i24 -> {i8, i8, i8}.
             let can_store_through_cast_ptr = false;
             if can_store_through_cast_ptr {
-                let cast_ptr_llty = bx.type_ptr_to(cast.llvm_type(bx));
-                let cast_dst = bx.pointercast(dst.llval, cast_ptr_llty);
-                bx.store(val, cast_dst, self.layout.align.abi);
+                bx.store(val, dst.llval, self.layout.align.abi);
             } else {
                 // The actual return type is a struct, but the ABI
                 // adaptation code has cast it into some scalar type. The
@@ -336,7 +334,7 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             PassMode::Direct(_) | PassMode::Pair(..) => self.ret.layout.immediate_llvm_type(cx),
             PassMode::Cast(cast, _) => cast.llvm_type(cx),
             PassMode::Indirect { .. } => {
-                llargument_tys.push(cx.type_ptr_to(self.ret.memory_ty(cx)));
+                llargument_tys.push(cx.type_ptr());
                 cx.type_void()
             }
         };
@@ -364,9 +362,7 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
                     }
                     cast.llvm_type(cx)
                 }
-                PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ } => {
-                    cx.type_ptr_to(arg.memory_ty(cx))
-                }
+                PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ } => cx.type_ptr(),
             };
             llargument_tys.push(llarg_ty);
         }
@@ -379,12 +375,7 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
     }
 
     fn ptr_to_llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
-        unsafe {
-            llvm::LLVMPointerType(
-                self.llvm_type(cx),
-                cx.data_layout().instruction_address_space.0 as c_uint,
-            )
-        }
+        cx.type_ptr_ext(cx.data_layout().instruction_address_space)
     }
 
     fn llvm_cconv(&self) -> llvm::CallConv {

compiler/rustc_codegen_llvm/src/allocator.rs

@@ -28,7 +28,7 @@ pub(crate) unsafe fn codegen(
         tws => bug!("Unsupported target word size for int: {}", tws),
     };
     let i8 = llvm::LLVMInt8TypeInContext(llcx);
-    let i8p = llvm::LLVMPointerType(i8, 0);
+    let i8p = llvm::LLVMPointerTypeInContext(llcx, 0);
     let void = llvm::LLVMVoidTypeInContext(llcx);
 
     if kind == AllocatorKind::Default {

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -4,7 +4,6 @@ use crate::back::profiling::{
 };
 use crate::base;
 use crate::common;
-use crate::consts;
 use crate::errors::{
     CopyBitcode, FromLlvmDiag, FromLlvmOptimizationDiag, LlvmError, WithLlvmError, WriteBytecode,
 };
@@ -992,7 +991,7 @@ fn create_msvc_imps(
     let prefix = if cgcx.target_arch == "x86" { "\x01__imp__" } else { "\x01__imp_" };
 
     unsafe {
-        let i8p_ty = Type::i8p_llcx(llcx);
+        let ptr_ty = Type::ptr_llcx(llcx);
         let globals = base::iter_globals(llmod)
             .filter(|&val| {
                 llvm::LLVMRustGetLinkage(val) == llvm::Linkage::ExternalLinkage
@@ -1012,8 +1011,8 @@ fn create_msvc_imps(
             .collect::<Vec<_>>();
 
         for (imp_name, val) in globals {
-            let imp = llvm::LLVMAddGlobal(llmod, i8p_ty, imp_name.as_ptr().cast());
-            llvm::LLVMSetInitializer(imp, consts::ptrcast(val, i8p_ty));
+            let imp = llvm::LLVMAddGlobal(llmod, ptr_ty, imp_name.as_ptr().cast());
+            llvm::LLVMSetInitializer(imp, val);
             llvm::LLVMRustSetLinkage(imp, llvm::Linkage::ExternalLinkage);
         }
     }

compiler/rustc_codegen_llvm/src/base.rs

@@ -123,8 +123,7 @@ pub fn compile_codegen_unit(tcx: TyCtxt<'_>, cgu_name: Symbol) -> (ModuleCodegen
             // happen after the llvm.used variables are created.
             for &(old_g, new_g) in cx.statics_to_rauw().borrow().iter() {
                 unsafe {
-                    let bitcast = llvm::LLVMConstPointerCast(new_g, cx.val_ty(old_g));
-                    llvm::LLVMReplaceAllUsesWith(old_g, bitcast);
+                    llvm::LLVMReplaceAllUsesWith(old_g, new_g);
                     llvm::LLVMDeleteGlobal(old_g);
                 }
             }

compiler/rustc_codegen_llvm/src/builder.rs

@@ -652,7 +652,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         flags: MemFlags,
     ) -> &'ll Value {
         debug!("Store {:?} -> {:?} ({:?})", val, ptr, flags);
-        let ptr = self.check_store(val, ptr);
+        let ptr = self.check_store(ptr);
         unsafe {
             let store = llvm::LLVMBuildStore(self.llbuilder, val, ptr);
             let align =
@@ -682,7 +682,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         size: Size,
     ) {
         debug!("Store {:?} -> {:?}", val, ptr);
-        let ptr = self.check_store(val, ptr);
+        let ptr = self.check_store(ptr);
         unsafe {
             let store = llvm::LLVMRustBuildAtomicStore(
                 self.llbuilder,
@@ -873,8 +873,6 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         assert!(!flags.contains(MemFlags::NONTEMPORAL), "non-temporal memcpy not supported");
         let size = self.intcast(size, self.type_isize(), false);
         let is_volatile = flags.contains(MemFlags::VOLATILE);
-        let dst = self.pointercast(dst, self.type_i8p());
-        let src = self.pointercast(src, self.type_i8p());
         unsafe {
             llvm::LLVMRustBuildMemCpy(
                 self.llbuilder,
@@ -900,8 +898,6 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         assert!(!flags.contains(MemFlags::NONTEMPORAL), "non-temporal memmove not supported");
         let size = self.intcast(size, self.type_isize(), false);
         let is_volatile = flags.contains(MemFlags::VOLATILE);
-        let dst = self.pointercast(dst, self.type_i8p());
-        let src = self.pointercast(src, self.type_i8p());
         unsafe {
             llvm::LLVMRustBuildMemMove(
                 self.llbuilder,
@@ -924,7 +920,6 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         flags: MemFlags,
     ) {
         let is_volatile = flags.contains(MemFlags::VOLATILE);
-        let ptr = self.pointercast(ptr, self.type_i8p());
         unsafe {
             llvm::LLVMRustBuildMemSet(
                 self.llbuilder,
@@ -981,7 +976,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     }
 
     fn cleanup_landing_pad(&mut self, pers_fn: &'ll Value) -> (&'ll Value, &'ll Value) {
-        let ty = self.type_struct(&[self.type_i8p(), self.type_i32()], false);
+        let ty = self.type_struct(&[self.type_ptr(), self.type_i32()], false);
         let landing_pad = self.landing_pad(ty, pers_fn, 0);
         unsafe {
             llvm::LLVMSetCleanup(landing_pad, llvm::True);
@@ -990,14 +985,14 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     }
 
     fn filter_landing_pad(&mut self, pers_fn: &'ll Value) -> (&'ll Value, &'ll Value) {
-        let ty = self.type_struct(&[self.type_i8p(), self.type_i32()], false);
+        let ty = self.type_struct(&[self.type_ptr(), self.type_i32()], false);
         let landing_pad = self.landing_pad(ty, pers_fn, 1);
-        self.add_clause(landing_pad, self.const_array(self.type_i8p(), &[]));
+        self.add_clause(landing_pad, self.const_array(self.type_ptr(), &[]));
         (self.extract_value(landing_pad, 0), self.extract_value(landing_pad, 1))
     }
 
     fn resume(&mut self, exn0: &'ll Value, exn1: &'ll Value) {
-        let ty = self.type_struct(&[self.type_i8p(), self.type_i32()], false);
+        let ty = self.type_struct(&[self.type_ptr(), self.type_i32()], false);
         let mut exn = self.const_poison(ty);
         exn = self.insert_value(exn, exn0, 0);
         exn = self.insert_value(exn, exn1, 1);
@@ -1161,7 +1156,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
 
         let llfn = unsafe { llvm::LLVMRustGetInstrProfIncrementIntrinsic(self.cx().llmod) };
         let llty = self.cx.type_func(
-            &[self.cx.type_i8p(), self.cx.type_i64(), self.cx.type_i32(), self.cx.type_i32()],
+            &[self.cx.type_ptr(), self.cx.type_i64(), self.cx.type_i32(), self.cx.type_i32()],
             self.cx.type_void(),
         );
         let args = &[fn_name, hash, num_counters, index];
@@ -1387,23 +1382,12 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
         ret.expect("LLVM does not have support for catchret")
     }
 
-    fn check_store(&mut self, val: &'ll Value, ptr: &'ll Value) -> &'ll Value {
+    fn check_store(&mut self, ptr: &'ll Value) -> &'ll Value {
         let dest_ptr_ty = self.cx.val_ty(ptr);
-        let stored_ty = self.cx.val_ty(val);
-        let stored_ptr_ty = self.cx.type_ptr_to(stored_ty);
 
         assert_eq!(self.cx.type_kind(dest_ptr_ty), TypeKind::Pointer);
 
-        if dest_ptr_ty == stored_ptr_ty {
-            ptr
-        } else {
-            debug!(
-                "type mismatch in store. \
-                    Expected {:?}, got {:?}; inserting bitcast",
-                dest_ptr_ty, stored_ptr_ty
-            );
-            self.bitcast(ptr, stored_ptr_ty)
-        }
+        ptr
     }
 
     fn check_call<'b>(
@@ -1468,7 +1452,6 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
             return;
         }
 
-        let ptr = self.pointercast(ptr, self.cx.type_i8p());
         self.call_intrinsic(intrinsic, &[self.cx.const_u64(size), ptr]);
     }
 

compiler/rustc_codegen_llvm/src/callee.rs

@@ -4,13 +4,11 @@
 //! and methods are represented as just a fn ptr and not a full
 //! closure.
 
-use crate::abi::FnAbiLlvmExt;
 use crate::attributes;
 use crate::common;
 use crate::context::CodegenCx;
 use crate::llvm;
 use crate::value::Value;
-use rustc_codegen_ssa::traits::*;
 
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt};
 use rustc_middle::ty::{self, Instance, TypeVisitableExt};
@@ -45,39 +43,7 @@ pub fn get_fn<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>, instance: Instance<'tcx>) ->
     let fn_abi = cx.fn_abi_of_instance(instance, ty::List::empty());
 
     let llfn = if let Some(llfn) = cx.get_declared_value(sym) {
-        // Create a fn pointer with the new signature.
-        let llptrty = fn_abi.ptr_to_llvm_type(cx);
-
-        // This is subtle and surprising, but sometimes we have to bitcast
-        // the resulting fn pointer. The reason has to do with external
-        // functions. If you have two crates that both bind the same C
-        // library, they may not use precisely the same types: for
-        // example, they will probably each declare their own structs,
-        // which are distinct types from LLVM's point of view (nominal
-        // types).
-        //
-        // Now, if those two crates are linked into an application, and
-        // they contain inlined code, you can wind up with a situation
-        // where both of those functions wind up being loaded into this
-        // application simultaneously. In that case, the same function
-        // (from LLVM's point of view) requires two types. But of course
-        // LLVM won't allow one function to have two types.
-        //
-        // What we currently do, therefore, is declare the function with
-        // one of the two types (whichever happens to come first) and then
-        // bitcast as needed when the function is referenced to make sure
-        // it has the type we expect.
-        //
-        // This can occur on either a crate-local or crate-external
-        // reference. It also occurs when testing libcore and in some
-        // other weird situations. Annoying.
-        if cx.val_ty(llfn) != llptrty {
-            debug!("get_fn: casting {:?} to {:?}", llfn, llptrty);
-            cx.const_ptrcast(llfn, llptrty)
-        } else {
-            debug!("get_fn: not casting pointer!");
-            llfn
-        }
+        llfn
     } else {
         let instance_def_id = instance.def_id();
         let llfn = if tcx.sess.target.arch == "x86" &&

compiler/rustc_codegen_llvm/src/common.rs

@@ -4,7 +4,6 @@ use crate::consts::{self, const_alloc_to_llvm};
 pub use crate::context::CodegenCx;
 use crate::llvm::{self, BasicBlock, Bool, ConstantInt, False, OperandBundleDef, True};
 use crate::type_::Type;
-use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
 
 use rustc_ast::Mutability;
@@ -13,7 +12,6 @@ use rustc_data_structures::stable_hasher::{Hash128, HashStable, StableHasher};
 use rustc_hir::def_id::DefId;
 use rustc_middle::bug;
 use rustc_middle::mir::interpret::{ConstAllocation, GlobalAlloc, Scalar};
-use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::cstore::{DllCallingConvention, DllImport, PeImportNameType};
 use rustc_target::abi::{self, AddressSpace, HasDataLayout, Pointer};
@@ -211,11 +209,7 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             })
             .1;
         let len = s.len();
-        let cs = consts::ptrcast(
-            str_global,
-            self.type_ptr_to(self.layout_of(self.tcx.types.str_).llvm_type(self)),
-        );
-        (cs, self.const_usize(len as u64))
+        (str_global, self.const_usize(len as u64))
     }
 
     fn const_struct(&self, elts: &[&'ll Value], packed: bool) -> &'ll Value {
@@ -292,7 +286,7 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                 let llval = unsafe {
                     llvm::LLVMConstInBoundsGEP2(
                         self.type_i8(),
-                        self.const_bitcast(base_addr, self.type_i8p_ext(base_addr_space)),
+                        self.const_bitcast(base_addr, self.type_ptr_ext(base_addr_space)),
                         &self.const_usize(offset.bytes()),
                         1,
                     )
@@ -322,7 +316,7 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         unsafe {
             llvm::LLVMConstInBoundsGEP2(
                 self.type_i8(),
-                self.const_bitcast(base_addr, self.type_i8p()),
+                base_addr,
                 &self.const_usize(offset.bytes()),
                 1,
             )

compiler/rustc_codegen_llvm/src/consts.rs

@@ -103,7 +103,7 @@ pub fn const_alloc_to_llvm<'ll>(cx: &CodegenCx<'ll, '_>, alloc: ConstAllocation<
                 value: Primitive::Pointer(address_space),
                 valid_range: WrappingRange::full(dl.pointer_size),
             },
-            cx.type_i8p_ext(address_space),
+            cx.type_ptr_ext(address_space),
         ));
         next_offset = offset + pointer_size;
     }
@@ -179,7 +179,7 @@ fn check_and_apply_linkage<'ll, 'tcx>(
                 })
             });
             llvm::LLVMRustSetLinkage(g2, llvm::Linkage::InternalLinkage);
-            llvm::LLVMSetInitializer(g2, cx.const_ptrcast(g1, llty));
+            llvm::LLVMSetInitializer(g2, g1);
             g2
         }
     } else if cx.tcx.sess.target.arch == "x86" &&
@@ -251,7 +251,7 @@ impl<'ll> CodegenCx<'ll, '_> {
         let g = if def_id.is_local() && !self.tcx.is_foreign_item(def_id) {
             let llty = self.layout_of(ty).llvm_type(self);
             if let Some(g) = self.get_declared_value(sym) {
-                if self.val_ty(g) != self.type_ptr_to(llty) {
+                if self.val_ty(g) != self.type_ptr() {
                     span_bug!(self.tcx.def_span(def_id), "Conflicting types for static");
                 }
             }
@@ -552,16 +552,14 @@ impl<'ll> StaticMethods for CodegenCx<'ll, '_> {
         }
     }
 
-    /// Add a global value to a list to be stored in the `llvm.used` variable, an array of i8*.
+    /// Add a global value to a list to be stored in the `llvm.used` variable, an array of ptr.
     fn add_used_global(&self, global: &'ll Value) {
-        let cast = unsafe { llvm::LLVMConstPointerCast(global, self.type_i8p()) };
-        self.used_statics.borrow_mut().push(cast);
+        self.used_statics.borrow_mut().push(global);
     }
 
     /// Add a global value to a list to be stored in the `llvm.compiler.used` variable,
-    /// an array of i8*.
+    /// an array of ptr.
     fn add_compiler_used_global(&self, global: &'ll Value) {
-        let cast = unsafe { llvm::LLVMConstPointerCast(global, self.type_i8p()) };
-        self.compiler_used_statics.borrow_mut().push(cast);
+        self.compiler_used_statics.borrow_mut().push(global);
     }
 }