mv compiler to compiler/

compiler/rustc_codegen_llvm/src/common.rs

@@ -0,0 +1,341 @@
+#![allow(non_camel_case_types, non_snake_case)]
+
+//! Code that is useful in various codegen modules.
+
+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;
+use rustc_codegen_ssa::mir::place::PlaceRef;
+use rustc_codegen_ssa::traits::*;
+use rustc_middle::bug;
+use rustc_middle::mir::interpret::{Allocation, GlobalAlloc, Scalar};
+use rustc_middle::ty::layout::TyAndLayout;
+use rustc_span::symbol::Symbol;
+use rustc_target::abi::{self, AddressSpace, HasDataLayout, LayoutOf, Pointer, Size};
+
+use libc::{c_char, c_uint};
+use tracing::debug;
+
+/*
+* A note on nomenclature of linking: "extern", "foreign", and "upcall".
+*
+* An "extern" is an LLVM symbol we wind up emitting an undefined external
+* reference to. This means "we don't have the thing in this compilation unit,
+* please make sure you link it in at runtime". This could be a reference to
+* C code found in a C library, or rust code found in a rust crate.
+*
+* Most "externs" are implicitly declared (automatically) as a result of a
+* user declaring an extern _module_ dependency; this causes the rust driver
+* to locate an extern crate, scan its compilation metadata, and emit extern
+* declarations for any symbols used by the declaring crate.
+*
+* A "foreign" is an extern that references C (or other non-rust ABI) code.
+* There is no metadata to scan for extern references so in these cases either
+* a header-digester like bindgen, or manual function prototypes, have to
+* serve as declarators. So these are usually given explicitly as prototype
+* declarations, in rust code, with ABI attributes on them noting which ABI to
+* link via.
+*
+* An "upcall" is a foreign call generated by the compiler (not corresponding
+* to any user-written call in the code) into the runtime library, to perform
+* some helper task such as bringing a task to life, allocating memory, etc.
+*
+*/
+
+/// A structure representing an active landing pad for the duration of a basic
+/// block.
+///
+/// Each `Block` may contain an instance of this, indicating whether the block
+/// is part of a landing pad or not. This is used to make decision about whether
+/// to emit `invoke` instructions (e.g., in a landing pad we don't continue to
+/// use `invoke`) and also about various function call metadata.
+///
+/// For GNU exceptions (`landingpad` + `resume` instructions) this structure is
+/// just a bunch of `None` instances (not too interesting), but for MSVC
+/// exceptions (`cleanuppad` + `cleanupret` instructions) this contains data.
+/// When inside of a landing pad, each function call in LLVM IR needs to be
+/// annotated with which landing pad it's a part of. This is accomplished via
+/// the `OperandBundleDef` value created for MSVC landing pads.
+pub struct Funclet<'ll> {
+    cleanuppad: &'ll Value,
+    operand: OperandBundleDef<'ll>,
+}
+
+impl Funclet<'ll> {
+    pub fn new(cleanuppad: &'ll Value) -> Self {
+        Funclet { cleanuppad, operand: OperandBundleDef::new("funclet", &[cleanuppad]) }
+    }
+
+    pub fn cleanuppad(&self) -> &'ll Value {
+        self.cleanuppad
+    }
+
+    pub fn bundle(&self) -> &OperandBundleDef<'ll> {
+        &self.operand
+    }
+}
+
+impl BackendTypes for CodegenCx<'ll, 'tcx> {
+    type Value = &'ll Value;
+    type Function = &'ll Value;
+
+    type BasicBlock = &'ll BasicBlock;
+    type Type = &'ll Type;
+    type Funclet = Funclet<'ll>;
+
+    type DIScope = &'ll llvm::debuginfo::DIScope;
+    type DIVariable = &'ll llvm::debuginfo::DIVariable;
+}
+
+impl CodegenCx<'ll, 'tcx> {
+    pub fn const_array(&self, ty: &'ll Type, elts: &[&'ll Value]) -> &'ll Value {
+        unsafe { llvm::LLVMConstArray(ty, elts.as_ptr(), elts.len() as c_uint) }
+    }
+
+    pub fn const_vector(&self, elts: &[&'ll Value]) -> &'ll Value {
+        unsafe { llvm::LLVMConstVector(elts.as_ptr(), elts.len() as c_uint) }
+    }
+
+    pub fn const_bytes(&self, bytes: &[u8]) -> &'ll Value {
+        bytes_in_context(self.llcx, bytes)
+    }
+
+    fn const_cstr(&self, s: Symbol, null_terminated: bool) -> &'ll Value {
+        unsafe {
+            if let Some(&llval) = self.const_cstr_cache.borrow().get(&s) {
+                return llval;
+            }
+
+            let s_str = s.as_str();
+            let sc = llvm::LLVMConstStringInContext(
+                self.llcx,
+                s_str.as_ptr() as *const c_char,
+                s_str.len() as c_uint,
+                !null_terminated as Bool,
+            );
+            let sym = self.generate_local_symbol_name("str");
+            let g = self.define_global(&sym[..], self.val_ty(sc)).unwrap_or_else(|| {
+                bug!("symbol `{}` is already defined", sym);
+            });
+            llvm::LLVMSetInitializer(g, sc);
+            llvm::LLVMSetGlobalConstant(g, True);
+            llvm::LLVMRustSetLinkage(g, llvm::Linkage::InternalLinkage);
+
+            self.const_cstr_cache.borrow_mut().insert(s, g);
+            g
+        }
+    }
+
+    pub fn const_get_elt(&self, v: &'ll Value, idx: u64) -> &'ll Value {
+        unsafe {
+            assert_eq!(idx as c_uint as u64, idx);
+            let us = &[idx as c_uint];
+            let r = llvm::LLVMConstExtractValue(v, us.as_ptr(), us.len() as c_uint);
+
+            debug!("const_get_elt(v={:?}, idx={}, r={:?})", v, idx, r);
+
+            r
+        }
+    }
+}
+
+impl ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
+    fn const_null(&self, t: &'ll Type) -> &'ll Value {
+        unsafe { llvm::LLVMConstNull(t) }
+    }
+
+    fn const_undef(&self, t: &'ll Type) -> &'ll Value {
+        unsafe { llvm::LLVMGetUndef(t) }
+    }
+
+    fn const_int(&self, t: &'ll Type, i: i64) -> &'ll Value {
+        unsafe { llvm::LLVMConstInt(t, i as u64, True) }
+    }
+
+    fn const_uint(&self, t: &'ll Type, i: u64) -> &'ll Value {
+        unsafe { llvm::LLVMConstInt(t, i, False) }
+    }
+
+    fn const_uint_big(&self, t: &'ll Type, u: u128) -> &'ll Value {
+        unsafe {
+            let words = [u as u64, (u >> 64) as u64];
+            llvm::LLVMConstIntOfArbitraryPrecision(t, 2, words.as_ptr())
+        }
+    }
+
+    fn const_bool(&self, val: bool) -> &'ll Value {
+        self.const_uint(self.type_i1(), val as u64)
+    }
+
+    fn const_i32(&self, i: i32) -> &'ll Value {
+        self.const_int(self.type_i32(), i as i64)
+    }
+
+    fn const_u32(&self, i: u32) -> &'ll Value {
+        self.const_uint(self.type_i32(), i as u64)
+    }
+
+    fn const_u64(&self, i: u64) -> &'ll Value {
+        self.const_uint(self.type_i64(), i)
+    }
+
+    fn const_usize(&self, i: u64) -> &'ll Value {
+        let bit_size = self.data_layout().pointer_size.bits();
+        if bit_size < 64 {
+            // make sure it doesn't overflow
+            assert!(i < (1 << bit_size));
+        }
+
+        self.const_uint(self.isize_ty, i)
+    }
+
+    fn const_u8(&self, i: u8) -> &'ll Value {
+        self.const_uint(self.type_i8(), i as u64)
+    }
+
+    fn const_real(&self, t: &'ll Type, val: f64) -> &'ll Value {
+        unsafe { llvm::LLVMConstReal(t, val) }
+    }
+
+    fn const_str(&self, s: Symbol) -> (&'ll Value, &'ll Value) {
+        let len = s.as_str().len();
+        let cs = consts::ptrcast(
+            self.const_cstr(s, false),
+            self.type_ptr_to(self.layout_of(self.tcx.types.str_).llvm_type(self)),
+        );
+        (cs, self.const_usize(len as u64))
+    }
+
+    fn const_struct(&self, elts: &[&'ll Value], packed: bool) -> &'ll Value {
+        struct_in_context(self.llcx, elts, packed)
+    }
+
+    fn const_to_opt_uint(&self, v: &'ll Value) -> Option<u64> {
+        try_as_const_integral(v).map(|v| unsafe { llvm::LLVMConstIntGetZExtValue(v) })
+    }
+
+    fn const_to_opt_u128(&self, v: &'ll Value, sign_ext: bool) -> Option<u128> {
+        try_as_const_integral(v).and_then(|v| unsafe {
+            let (mut lo, mut hi) = (0u64, 0u64);
+            let success = llvm::LLVMRustConstInt128Get(v, sign_ext, &mut hi, &mut lo);
+            success.then_some(hi_lo_to_u128(lo, hi))
+        })
+    }
+
+    fn scalar_to_backend(&self, cv: Scalar, layout: &abi::Scalar, llty: &'ll Type) -> &'ll Value {
+        let bitsize = if layout.is_bool() { 1 } else { layout.value.size(self).bits() };
+        match cv {
+            Scalar::Raw { size: 0, .. } => {
+                assert_eq!(0, layout.value.size(self).bytes());
+                self.const_undef(self.type_ix(0))
+            }
+            Scalar::Raw { data, size } => {
+                assert_eq!(size as u64, layout.value.size(self).bytes());
+                let llval = self.const_uint_big(self.type_ix(bitsize), data);
+                if layout.value == Pointer {
+                    unsafe { llvm::LLVMConstIntToPtr(llval, llty) }
+                } else {
+                    self.const_bitcast(llval, llty)
+                }
+            }
+            Scalar::Ptr(ptr) => {
+                let (base_addr, base_addr_space) = match self.tcx.global_alloc(ptr.alloc_id) {
+                    GlobalAlloc::Memory(alloc) => {
+                        let init = const_alloc_to_llvm(self, alloc);
+                        let value = match alloc.mutability {
+                            Mutability::Mut => self.static_addr_of_mut(init, alloc.align, None),
+                            _ => self.static_addr_of(init, alloc.align, None),
+                        };
+                        if !self.sess().fewer_names() {
+                            llvm::set_value_name(value, format!("{:?}", ptr.alloc_id).as_bytes());
+                        }
+                        (value, AddressSpace::DATA)
+                    }
+                    GlobalAlloc::Function(fn_instance) => (
+                        self.get_fn_addr(fn_instance.polymorphize(self.tcx)),
+                        self.data_layout().instruction_address_space,
+                    ),
+                    GlobalAlloc::Static(def_id) => {
+                        assert!(self.tcx.is_static(def_id));
+                        assert!(!self.tcx.is_thread_local_static(def_id));
+                        (self.get_static(def_id), AddressSpace::DATA)
+                    }
+                };
+                let llval = unsafe {
+                    llvm::LLVMConstInBoundsGEP(
+                        self.const_bitcast(base_addr, self.type_i8p_ext(base_addr_space)),
+                        &self.const_usize(ptr.offset.bytes()),
+                        1,
+                    )
+                };
+                if layout.value != Pointer {
+                    unsafe { llvm::LLVMConstPtrToInt(llval, llty) }
+                } else {
+                    self.const_bitcast(llval, llty)
+                }
+            }
+        }
+    }
+
+    fn from_const_alloc(
+        &self,
+        layout: TyAndLayout<'tcx>,
+        alloc: &Allocation,
+        offset: Size,
+    ) -> PlaceRef<'tcx, &'ll Value> {
+        assert_eq!(alloc.align, layout.align.abi);
+        let llty = self.type_ptr_to(layout.llvm_type(self));
+        let llval = if layout.size == Size::ZERO {
+            let llval = self.const_usize(alloc.align.bytes());
+            unsafe { llvm::LLVMConstIntToPtr(llval, llty) }
+        } else {
+            let init = const_alloc_to_llvm(self, alloc);
+            let base_addr = self.static_addr_of(init, alloc.align, None);
+
+            let llval = unsafe {
+                llvm::LLVMConstInBoundsGEP(
+                    self.const_bitcast(base_addr, self.type_i8p()),
+                    &self.const_usize(offset.bytes()),
+                    1,
+                )
+            };
+            self.const_bitcast(llval, llty)
+        };
+        PlaceRef::new_sized(llval, layout)
+    }
+
+    fn const_ptrcast(&self, val: &'ll Value, ty: &'ll Type) -> &'ll Value {
+        consts::ptrcast(val, ty)
+    }
+}
+
+pub fn val_ty(v: &Value) -> &Type {
+    unsafe { llvm::LLVMTypeOf(v) }
+}
+
+pub fn bytes_in_context(llcx: &'ll llvm::Context, bytes: &[u8]) -> &'ll Value {
+    unsafe {
+        let ptr = bytes.as_ptr() as *const c_char;
+        llvm::LLVMConstStringInContext(llcx, ptr, bytes.len() as c_uint, True)
+    }
+}
+
+pub fn struct_in_context(llcx: &'a llvm::Context, elts: &[&'a Value], packed: bool) -> &'a Value {
+    unsafe {
+        llvm::LLVMConstStructInContext(llcx, elts.as_ptr(), elts.len() as c_uint, packed as Bool)
+    }
+}
+
+#[inline]
+fn hi_lo_to_u128(lo: u64, hi: u64) -> u128 {
+    ((hi as u128) << 64) | (lo as u128)
+}
+
+fn try_as_const_integral(v: &Value) -> Option<&ConstantInt> {
+    unsafe { llvm::LLVMIsAConstantInt(v) }
+}