| //! 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::{ConstAllocation, GlobalAlloc, Scalar}; |
| use rustc_middle::ty::layout::{LayoutOf, TyAndLayout}; |
| use rustc_middle::ty::ScalarInt; |
| use rustc_span::symbol::Symbol; |
| use rustc_target::abi::{self, AddressSpace, HasDataLayout, 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<'ll> 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<'ll> BackendTypes for CodegenCx<'ll, '_> { |
| type Value = &'ll Value; |
| // FIXME(eddyb) replace this with a `Function` "subclass" of `Value`. |
| type Function = &'ll Value; |
| |
| type BasicBlock = &'ll BasicBlock; |
| type Type = &'ll Type; |
| type Funclet = Funclet<'ll>; |
| |
| type DIScope = &'ll llvm::debuginfo::DIScope; |
| type DILocation = &'ll llvm::debuginfo::DILocation; |
| type DIVariable = &'ll llvm::debuginfo::DIVariable; |
| } |
| |
| impl<'ll> CodegenCx<'ll, '_> { |
| 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) |
| } |
| |
| 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<'ll, 'tcx> 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_i16(&self, i: i16) -> &'ll Value { |
| self.const_int(self.type_i16(), i as i64) |
| } |
| |
| 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 s_str = s.as_str(); |
| let str_global = *self.const_str_cache.borrow_mut().entry(s).or_insert_with(|| { |
| let sc = self.const_bytes(s_str.as_bytes()); |
| 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); |
| }); |
| unsafe { |
| llvm::LLVMSetInitializer(g, sc); |
| llvm::LLVMSetGlobalConstant(g, True); |
| llvm::LLVMRustSetLinkage(g, llvm::Linkage::InternalLinkage); |
| } |
| g |
| }); |
| let len = s_str.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)) |
| } |
| |
| 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.size(self).bits() }; |
| match cv { |
| Scalar::Int(ScalarInt::ZST) => { |
| assert_eq!(0, layout.size(self).bytes()); |
| self.const_undef(self.type_ix(0)) |
| } |
| Scalar::Int(int) => { |
| let data = int.assert_bits(layout.size(self)); |
| let llval = self.const_uint_big(self.type_ix(bitsize), data); |
| if layout.primitive() == Pointer { |
| unsafe { llvm::LLVMConstIntToPtr(llval, llty) } |
| } else { |
| self.const_bitcast(llval, llty) |
| } |
| } |
| Scalar::Ptr(ptr, _size) => { |
| let (alloc_id, offset) = ptr.into_parts(); |
| let (base_addr, base_addr_space) = match self.tcx.global_alloc(alloc_id) { |
| GlobalAlloc::Memory(alloc) => { |
| let init = const_alloc_to_llvm(self, alloc); |
| let alloc = alloc.inner(); |
| 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!("{:?}", 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::LLVMRustConstInBoundsGEP2( |
| self.type_i8(), |
| self.const_bitcast(base_addr, self.type_i8p_ext(base_addr_space)), |
| &self.const_usize(offset.bytes()), |
| 1, |
| ) |
| }; |
| if layout.primitive() != Pointer { |
| unsafe { llvm::LLVMConstPtrToInt(llval, llty) } |
| } else { |
| self.const_bitcast(llval, llty) |
| } |
| } |
| } |
| } |
| |
| fn const_data_from_alloc(&self, alloc: ConstAllocation<'tcx>) -> Self::Value { |
| const_alloc_to_llvm(self, alloc) |
| } |
| |
| fn from_const_alloc( |
| &self, |
| layout: TyAndLayout<'tcx>, |
| alloc: ConstAllocation<'tcx>, |
| offset: Size, |
| ) -> PlaceRef<'tcx, &'ll Value> { |
| let alloc_align = alloc.inner().align; |
| 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::LLVMRustConstInBoundsGEP2( |
| self.type_i8(), |
| 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) |
| } |
| } |
| |
| /// Get the [LLVM type][Type] of a [`Value`]. |
| pub fn val_ty(v: &Value) -> &Type { |
| unsafe { llvm::LLVMTypeOf(v) } |
| } |
| |
| pub fn bytes_in_context<'ll>(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<'ll>( |
| llcx: &'ll llvm::Context, |
| elts: &[&'ll Value], |
| packed: bool, |
| ) -> &'ll 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) } |
| } |
