| //! Code that is useful in various codegen modules. |
| |
| use crate::consts::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::value::Value; |
| |
| use rustc_ast::Mutability; |
| use rustc_codegen_ssa::traits::*; |
| 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::TyCtxt; |
| use rustc_session::cstore::{DllCallingConvention, DllImport, PeImportNameType}; |
| use rustc_target::abi::{self, AddressSpace, HasDataLayout, Pointer}; |
| use rustc_target::spec::Target; |
| |
| use libc::{c_char, c_uint}; |
| use std::fmt::Write; |
| |
| /* |
| * 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 r = llvm::LLVMGetAggregateElement(v, idx as c_uint).unwrap(); |
| |
| 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_poison(&self, t: &'ll Type) -> &'ll Value { |
| unsafe { llvm::LLVMGetPoison(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_u128(&self, i: u128) -> &'ll Value { |
| self.const_uint_big(self.type_i128(), 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: &str) -> (&'ll Value, &'ll Value) { |
| let str_global = *self |
| .const_str_cache |
| .borrow_mut() |
| .raw_entry_mut() |
| .from_key(s) |
| .or_insert_with(|| { |
| let sc = self.const_bytes(s.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); |
| } |
| (s.to_owned(), g) |
| }) |
| .1; |
| let len = s.len(); |
| (str_global, 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).and_then(|v| unsafe { |
| let mut i = 0u64; |
| let success = llvm::LLVMRustConstIntGetZExtValue(v, &mut i); |
| success.then_some(i) |
| }) |
| } |
| |
| 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(int) => { |
| let data = int.assert_bits(layout.size(self)); |
| let llval = self.const_uint_big(self.type_ix(bitsize), data); |
| if matches!(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::get_value_name(value).is_empty() { |
| let hash = self.tcx.with_stable_hashing_context(|mut hcx| { |
| let mut hasher = StableHasher::new(); |
| alloc.hash_stable(&mut hcx, &mut hasher); |
| hasher.finish::<Hash128>() |
| }); |
| llvm::set_value_name(value, format!("alloc_{hash:032x}").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::VTable(ty, trait_ref) => { |
| let alloc = self |
| .tcx |
| .global_alloc(self.tcx.vtable_allocation((ty, trait_ref))) |
| .unwrap_memory(); |
| let init = const_alloc_to_llvm(self, alloc); |
| let value = self.static_addr_of(init, alloc.inner().align, None); |
| (value, AddressSpace::DATA) |
| } |
| 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::LLVMConstInBoundsGEP2( |
| self.type_i8(), |
| self.const_bitcast(base_addr, self.type_ptr_ext(base_addr_space)), |
| &self.const_usize(offset.bytes()), |
| 1, |
| ) |
| }; |
| if !matches!(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 const_bitcast(&self, val: &'ll Value, ty: &'ll Type) -> &'ll Value { |
| self.const_bitcast(val, ty) |
| } |
| |
| fn const_ptr_byte_offset(&self, base_addr: Self::Value, offset: abi::Size) -> Self::Value { |
| unsafe { |
| llvm::LLVMConstInBoundsGEP2( |
| self.type_i8(), |
| base_addr, |
| &self.const_usize(offset.bytes()), |
| 1, |
| ) |
| } |
| } |
| } |
| |
| /// 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) } |
| } |
| |
| pub(crate) fn get_dllimport<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| id: DefId, |
| name: &str, |
| ) -> Option<&'tcx DllImport> { |
| tcx.native_library(id) |
| .and_then(|lib| lib.dll_imports.iter().find(|di| di.name.as_str() == name)) |
| } |
| |
| pub(crate) fn is_mingw_gnu_toolchain(target: &Target) -> bool { |
| target.vendor == "pc" && target.os == "windows" && target.env == "gnu" && target.abi.is_empty() |
| } |
| |
| pub(crate) fn i686_decorated_name( |
| dll_import: &DllImport, |
| mingw: bool, |
| disable_name_mangling: bool, |
| ) -> String { |
| let name = dll_import.name.as_str(); |
| |
| let (add_prefix, add_suffix) = match dll_import.import_name_type { |
| Some(PeImportNameType::NoPrefix) => (false, true), |
| Some(PeImportNameType::Undecorated) => (false, false), |
| _ => (true, true), |
| }; |
| |
| // Worst case: +1 for disable name mangling, +1 for prefix, +4 for suffix (@@__). |
| let mut decorated_name = String::with_capacity(name.len() + 6); |
| |
| if disable_name_mangling { |
| // LLVM uses a binary 1 ('\x01') prefix to a name to indicate that mangling needs to be disabled. |
| decorated_name.push('\x01'); |
| } |
| |
| let prefix = if add_prefix && dll_import.is_fn { |
| match dll_import.calling_convention { |
| DllCallingConvention::C | DllCallingConvention::Vectorcall(_) => None, |
| DllCallingConvention::Stdcall(_) => (!mingw |
| || dll_import.import_name_type == Some(PeImportNameType::Decorated)) |
| .then_some('_'), |
| DllCallingConvention::Fastcall(_) => Some('@'), |
| } |
| } else if !dll_import.is_fn && !mingw { |
| // For static variables, prefix with '_' on MSVC. |
| Some('_') |
| } else { |
| None |
| }; |
| if let Some(prefix) = prefix { |
| decorated_name.push(prefix); |
| } |
| |
| decorated_name.push_str(name); |
| |
| if add_suffix && dll_import.is_fn { |
| match dll_import.calling_convention { |
| DllCallingConvention::C => {} |
| DllCallingConvention::Stdcall(arg_list_size) |
| | DllCallingConvention::Fastcall(arg_list_size) => { |
| write!(&mut decorated_name, "@{arg_list_size}").unwrap(); |
| } |
| DllCallingConvention::Vectorcall(arg_list_size) => { |
| write!(&mut decorated_name, "@@{arg_list_size}").unwrap(); |
| } |
| } |
| } |
| |
| decorated_name |
| } |
