Auto merge of #54012 - denismerigoux:cg-llvm-gen, r=<try>

rustc_codegen_llvm: traitification of LLVM-specific CodegenCx and Builder methods

This PR is the continuation of #52461 in the grand plan of #45274 to allow for multiple codegen backends. A first attempt at this was #52987 but since @irinagpopa is no longer working on it I'm taking ownership of the PR.

The changes are refactoring only and do not affect the logic of the code. Performance should not be impacted since all parametrization is done with generics (no trait objects).

The `librustc_codegen_llvm` crate now contains a new folder `interfaces` that describes with traits part of how the compiler interfaces with LLVM during codegen. `CodegenCx` and `Builder` implement those traits.

Many things are still missing. All the calls to LLVM are not yet under a trait, and later LLVM-agnostic code should be parametrized.

src/librustc_codegen_llvm/abi.rs

@@ -11,14 +11,16 @@
 use llvm::{self, AttributePlace};
 use base;
 use builder::{Builder, MemFlags};
-use common::{ty_fn_sig, C_usize};
+use common::ty_fn_sig;
 use context::CodegenCx;
 use mir::place::PlaceRef;
 use mir::operand::OperandValue;
 use type_::Type;
 use type_of::{LayoutLlvmExt, PointerKind};
 use value::Value;
 
+use interfaces::{BuilderMethods, ConstMethods, TypeMethods};
+
 use rustc_target::abi::{LayoutOf, Size, TyLayout};
 use rustc::ty::{self, Ty};
 use rustc::ty::layout;
@@ -104,29 +106,29 @@ impl ArgAttributesExt for ArgAttributes {
 }
 
 pub trait LlvmType {
-    fn llvm_type(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type;
+    fn llvm_type(&self, cx: &CodegenCx<'ll, '_, &'ll Value>) -> &'ll Type;
 }
 
 impl LlvmType for Reg {
-    fn llvm_type(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type {
+    fn llvm_type(&self, cx: &CodegenCx<'ll, '_, &'ll Value>) -> &'ll Type {
         match self.kind {
-            RegKind::Integer => Type::ix(cx, self.size.bits()),
+            RegKind::Integer => cx.type_ix(self.size.bits()),
             RegKind::Float => {
                 match self.size.bits() {
-                    32 => Type::f32(cx),
-                    64 => Type::f64(cx),
+                    32 => cx.type_f32(),
+                    64 => cx.type_f64(),
                     _ => bug!("unsupported float: {:?}", self)
                 }
             }
             RegKind::Vector => {
-                Type::vector(Type::i8(cx), self.size.bytes())
+                cx.type_vector(cx.type_i8(), self.size.bytes())
             }
         }
     }
 }
 
 impl LlvmType for CastTarget {
-    fn llvm_type(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type {
+    fn llvm_type(&self, cx: &CodegenCx<'ll, '_, &'ll Value>) -> &'ll Type {
         let rest_ll_unit = self.rest.unit.llvm_type(cx);
         let (rest_count, rem_bytes) = if self.rest.unit.size.bytes() == 0 {
             (0, 0)
@@ -143,7 +145,7 @@ impl LlvmType for CastTarget {
 
             // Simplify to array when all chunks are the same size and type
             if rem_bytes == 0 {
-                return Type::array(rest_ll_unit, rest_count);
+                return cx.type_array(rest_ll_unit, rest_count);
             }
         }
 
@@ -158,35 +160,49 @@ impl LlvmType for CastTarget {
         if rem_bytes != 0 {
             // Only integers can be really split further.
             assert_eq!(self.rest.unit.kind, RegKind::Integer);
-            args.push(Type::ix(cx, rem_bytes * 8));
+            args.push(cx.type_ix(rem_bytes * 8));
         }
 
-        Type::struct_(cx, &args, false)
+        cx.type_struct(&args, false)
     }
 }
 
 pub trait ArgTypeExt<'ll, 'tcx> {
-    fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
-    fn store(&self, bx: &Builder<'_, 'll, 'tcx>, val: &'ll Value, dst: PlaceRef<'ll, 'tcx>);
-    fn store_fn_arg(&self, bx: &Builder<'_, 'll, 'tcx>, idx: &mut usize, dst: PlaceRef<'ll, 'tcx>);
+    fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx, &'ll Value>) -> &'ll Type;
+    fn store(
+        &self,
+        bx: &Builder<'_, 'll, 'tcx, &'ll Value>,
+        val: &'ll Value,
+        dst: PlaceRef<'tcx, &'ll Value>
+    );
+    fn store_fn_arg(
+        &self,
+        bx: &Builder<'_, 'll, 'tcx, &'ll Value>,
+        idx: &mut usize, dst: PlaceRef<'tcx, &'ll Value>
+    );
 }
 
 impl ArgTypeExt<'ll, 'tcx> for ArgType<'tcx, Ty<'tcx>> {
     /// Get the LLVM type for a place of the original Rust type of
     /// this argument/return, i.e. the result of `type_of::type_of`.
-    fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
+    fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx, &'ll Value>) -> &'ll Type {
         self.layout.llvm_type(cx)
     }
 
     /// Store a direct/indirect value described by this ArgType into a
     /// place for the original Rust type of this argument/return.
     /// Can be used for both storing formal arguments into Rust variables
     /// or results of call/invoke instructions into their destinations.
-    fn store(&self, bx: &Builder<'_, 'll, 'tcx>, val: &'ll Value, dst: PlaceRef<'ll, 'tcx>) {
+    fn store(
+        &self,
+        bx: &Builder<'_, 'll, 'tcx, &'ll Value>,
+        val: &'ll Value,
+        dst: PlaceRef<'tcx, &'ll Value>
+    ) {
         if self.is_ignore() {
             return;
         }
-        let cx = bx.cx;
+        let cx = bx.cx();
         if self.is_sized_indirect() {
             OperandValue::Ref(val, None, self.layout.align).store(bx, dst)
         } else if self.is_unsized_indirect() {
@@ -196,7 +212,7 @@ impl ArgTypeExt<'ll, 'tcx> for ArgType<'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_dst = bx.pointercast(dst.llval, cast.llvm_type(cx).ptr_to());
+                let cast_dst = bx.pointercast(dst.llval, cx.type_ptr_to(cast.llvm_type(cx)));
                 bx.store(val, cast_dst, self.layout.align);
             } else {
                 // The actual return type is a struct, but the ABI
@@ -224,9 +240,9 @@ impl ArgTypeExt<'ll, 'tcx> for ArgType<'tcx, Ty<'tcx>> {
 
                 // ...and then memcpy it to the intended destination.
                 base::call_memcpy(bx,
-                                  bx.pointercast(dst.llval, Type::i8p(cx)),
-                                  bx.pointercast(llscratch, Type::i8p(cx)),
-                                  C_usize(cx, self.layout.size.bytes()),
+                                  bx.pointercast(dst.llval, cx.type_i8p()),
+                                  bx.pointercast(llscratch, cx.type_i8p()),
+                                  cx.const_usize(self.layout.size.bytes()),
                                   self.layout.align.min(scratch_align),
                                   MemFlags::empty());
 
@@ -237,7 +253,12 @@ impl ArgTypeExt<'ll, 'tcx> for ArgType<'tcx, Ty<'tcx>> {
         }
     }
 
-    fn store_fn_arg(&self, bx: &Builder<'a, 'll, 'tcx>, idx: &mut usize, dst: PlaceRef<'ll, 'tcx>) {
+    fn store_fn_arg(
+        &self,
+        bx: &Builder<'a, 'll, 'tcx, &'ll Value>,
+        idx: &mut usize,
+        dst: PlaceRef<'tcx, &'ll Value>
+    ) {
         let mut next = || {
             let val = llvm::get_param(bx.llfn(), *idx as c_uint);
             *idx += 1;
@@ -259,47 +280,47 @@ impl ArgTypeExt<'ll, 'tcx> for ArgType<'tcx, Ty<'tcx>> {
 }
 
 pub trait FnTypeExt<'tcx> {
-    fn of_instance(cx: &CodegenCx<'ll, 'tcx>, instance: &ty::Instance<'tcx>)
+    fn of_instance(cx: &CodegenCx<'ll, 'tcx, &'ll Value>, instance: &ty::Instance<'tcx>)
                    -> Self;
-    fn new(cx: &CodegenCx<'ll, 'tcx>,
+    fn new(cx: &CodegenCx<'ll, 'tcx, &'ll Value>,
            sig: ty::FnSig<'tcx>,
            extra_args: &[Ty<'tcx>]) -> Self;
-    fn new_vtable(cx: &CodegenCx<'ll, 'tcx>,
+    fn new_vtable(cx: &CodegenCx<'ll, 'tcx, &'ll Value>,
                   sig: ty::FnSig<'tcx>,
                   extra_args: &[Ty<'tcx>]) -> Self;
     fn new_internal(
-        cx: &CodegenCx<'ll, 'tcx>,
+        cx: &CodegenCx<'ll, 'tcx, &'ll Value>,
         sig: ty::FnSig<'tcx>,
         extra_args: &[Ty<'tcx>],
         mk_arg_type: impl Fn(Ty<'tcx>, Option<usize>) -> ArgType<'tcx, Ty<'tcx>>,
     ) -> Self;
     fn adjust_for_abi(&mut self,
-                      cx: &CodegenCx<'ll, 'tcx>,
+                      cx: &CodegenCx<'ll, 'tcx, &'ll Value>,
                       abi: Abi);
-    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
+    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx, &'ll Value>) -> &'ll Type;
     fn llvm_cconv(&self) -> llvm::CallConv;
     fn apply_attrs_llfn(&self, llfn: &'ll Value);
-    fn apply_attrs_callsite(&self, bx: &Builder<'a, 'll, 'tcx>, callsite: &'ll Value);
+    fn apply_attrs_callsite(&self, bx: &Builder<'a, 'll, 'tcx, &'ll Value>, callsite: &'ll Value);
 }
 
 impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
-    fn of_instance(cx: &CodegenCx<'ll, 'tcx>, instance: &ty::Instance<'tcx>)
+    fn of_instance(cx: &CodegenCx<'ll, 'tcx, &'ll Value>, instance: &ty::Instance<'tcx>)
                        -> Self {
         let fn_ty = instance.ty(cx.tcx);
         let sig = ty_fn_sig(cx, fn_ty);
         let sig = cx.tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
         FnType::new(cx, sig, &[])
     }
 
-    fn new(cx: &CodegenCx<'ll, 'tcx>,
+    fn new(cx: &CodegenCx<'ll, 'tcx, &'ll Value>,
                sig: ty::FnSig<'tcx>,
                extra_args: &[Ty<'tcx>]) -> Self {
         FnType::new_internal(cx, sig, extra_args, |ty, _| {
             ArgType::new(cx.layout_of(ty))
         })
     }
 
-    fn new_vtable(cx: &CodegenCx<'ll, 'tcx>,
+    fn new_vtable(cx: &CodegenCx<'ll, 'tcx, &'ll Value>,
                       sig: ty::FnSig<'tcx>,
                       extra_args: &[Ty<'tcx>]) -> Self {
         FnType::new_internal(cx, sig, extra_args, |ty, arg_idx| {
@@ -326,7 +347,7 @@ impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
     }
 
     fn new_internal(
-        cx: &CodegenCx<'ll, 'tcx>,
+        cx: &CodegenCx<'ll, 'tcx, &'ll Value>,
         sig: ty::FnSig<'tcx>,
         extra_args: &[Ty<'tcx>],
         mk_arg_type: impl Fn(Ty<'tcx>, Option<usize>) -> ArgType<'tcx, Ty<'tcx>>,
@@ -507,7 +528,7 @@ impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
     }
 
     fn adjust_for_abi(&mut self,
-                      cx: &CodegenCx<'ll, 'tcx>,
+                      cx: &CodegenCx<'ll, 'tcx, &'ll Value>,
                       abi: Abi) {
         if abi == Abi::Unadjusted { return }
 
@@ -574,7 +595,7 @@ impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
         }
     }
 
-    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
+    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx, &'ll Value>) -> &'ll Type {
         let args_capacity: usize = self.args.iter().map(|arg|
             if arg.pad.is_some() { 1 } else { 0 } +
             if let PassMode::Pair(_, _) = arg.mode { 2 } else { 1 }
@@ -584,14 +605,14 @@ impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
         );
 
         let llreturn_ty = match self.ret.mode {
-            PassMode::Ignore => Type::void(cx),
+            PassMode::Ignore => cx.type_void(),
             PassMode::Direct(_) | PassMode::Pair(..) => {
                 self.ret.layout.immediate_llvm_type(cx)
             }
             PassMode::Cast(cast) => cast.llvm_type(cx),
             PassMode::Indirect(..) => {
-                llargument_tys.push(self.ret.memory_ty(cx).ptr_to());
-                Type::void(cx)
+                llargument_tys.push(cx.type_ptr_to(self.ret.memory_ty(cx)));
+                cx.type_void()
             }
         };
 
@@ -617,15 +638,15 @@ impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
                     continue;
                 }
                 PassMode::Cast(cast) => cast.llvm_type(cx),
-                PassMode::Indirect(_, None) => arg.memory_ty(cx).ptr_to(),
+                PassMode::Indirect(_, None) => cx.type_ptr_to(arg.memory_ty(cx)),
             };
             llargument_tys.push(llarg_ty);
         }
 
         if self.variadic {
-            Type::variadic_func(&llargument_tys, llreturn_ty)
+            cx.type_variadic_func(&llargument_tys, llreturn_ty)
         } else {
-            Type::func(&llargument_tys, llreturn_ty)
+            cx.type_func(&llargument_tys, llreturn_ty)
         }
     }
 
@@ -680,7 +701,7 @@ impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
         }
     }
 
-    fn apply_attrs_callsite(&self, bx: &Builder<'a, 'll, 'tcx>, callsite: &'ll Value) {
+    fn apply_attrs_callsite(&self, bx: &Builder<'a, 'll, 'tcx, &'ll Value>, callsite: &'ll Value) {
         let mut i = 0;
         let mut apply = |attrs: &ArgAttributes| {
             attrs.apply_callsite(llvm::AttributePlace::Argument(i), callsite);
@@ -699,7 +720,7 @@ impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
             // by the LLVM verifier.
             match scalar.value {
                 layout::Int(..) if !scalar.is_bool() => {
-                    let range = scalar.valid_range_exclusive(bx.cx);
+                    let range = scalar.valid_range_exclusive(bx.cx());
                     if range.start != range.end {
                         bx.range_metadata(callsite, range);
                     }

src/librustc_codegen_llvm/asm.rs

@@ -9,26 +9,25 @@
 // except according to those terms.
 
 use llvm;
-use common::*;
-use type_::Type;
+use context::CodegenCx;
 use type_of::LayoutLlvmExt;
 use builder::Builder;
 use value::Value;
 
 use rustc::hir;
+use interfaces::{BuilderMethods, ConstMethods, TypeMethods};
 
 use mir::place::PlaceRef;
 use mir::operand::OperandValue;
 
 use std::ffi::CString;
-use syntax::ast::AsmDialect;
 use libc::{c_uint, c_char};
 
 // Take an inline assembly expression and splat it out via LLVM
 pub fn codegen_inline_asm(
-    bx: &Builder<'a, 'll, 'tcx>,
+    bx: &Builder<'a, 'll, 'tcx, &'ll Value>,
     ia: &hir::InlineAsm,
-    outputs: Vec<PlaceRef<'ll, 'tcx>>,
+    outputs: Vec<PlaceRef<'tcx, &'ll Value>>,
     mut inputs: Vec<&'ll Value>
 ) {
     let mut ext_constraints = vec![];
@@ -44,7 +43,7 @@ pub fn codegen_inline_asm(
         if out.is_indirect {
             indirect_outputs.push(place.load(bx).immediate());
         } else {
-            output_types.push(place.layout.llvm_type(bx.cx));
+            output_types.push(place.layout.llvm_type(bx.cx()));
         }
     }
     if !indirect_outputs.is_empty() {
@@ -76,14 +75,9 @@ pub fn codegen_inline_asm(
     // Depending on how many outputs we have, the return type is different
     let num_outputs = output_types.len();
     let output_type = match num_outputs {
-        0 => Type::void(bx.cx),
+        0 => bx.cx().type_void(),
         1 => output_types[0],
-        _ => Type::struct_(bx.cx, &output_types, false)
-    };
-
-    let dialect = match ia.dialect {
-        AsmDialect::Att   => llvm::AsmDialect::Att,
-        AsmDialect::Intel => llvm::AsmDialect::Intel,
+        _ => bx.cx().type_struct(&output_types, false)
     };
 
     let asm = CString::new(ia.asm.as_str().as_bytes()).unwrap();
@@ -95,7 +89,7 @@ pub fn codegen_inline_asm(
         output_type,
         ia.volatile,
         ia.alignstack,
-        dialect
+        ia.dialect
     );
 
     // Again, based on how many outputs we have
@@ -109,17 +103,17 @@ pub fn codegen_inline_asm(
     // back to source locations.  See #17552.
     unsafe {
         let key = "srcloc";
-        let kind = llvm::LLVMGetMDKindIDInContext(bx.cx.llcx,
+        let kind = llvm::LLVMGetMDKindIDInContext(bx.cx().llcx,
             key.as_ptr() as *const c_char, key.len() as c_uint);
 
-        let val: &'ll Value = C_i32(bx.cx, ia.ctxt.outer().as_u32() as i32);
+        let val: &'ll Value = bx.cx().const_i32(ia.ctxt.outer().as_u32() as i32);
 
         llvm::LLVMSetMetadata(r, kind,
-            llvm::LLVMMDNodeInContext(bx.cx.llcx, &val, 1));
+            llvm::LLVMMDNodeInContext(bx.cx().llcx, &val, 1));
     }
 }
 
-pub fn codegen_global_asm<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
+pub fn codegen_global_asm<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx, &'a Value>,
                                   ga: &hir::GlobalAsm) {
     let asm = CString::new(ga.asm.as_str().as_bytes()).unwrap();
     unsafe {