1241 lines
48 KiB
Rust
1241 lines
48 KiB
Rust
use rustc::middle::lang_items;
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use rustc::ty::{self, Ty, TypeFoldable, Instance};
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use rustc::ty::layout::{self, LayoutOf, HasTyCtxt, FnTypeExt};
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use rustc::mir::{self, Place, PlaceBase, Static, StaticKind};
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use rustc::mir::interpret::InterpError;
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use rustc_target::abi::call::{ArgType, FnType, PassMode, IgnoreMode};
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use rustc_target::spec::abi::Abi;
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use crate::base;
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use crate::MemFlags;
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use crate::common::{self, IntPredicate};
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use crate::meth;
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use crate::traits::*;
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use std::borrow::Cow;
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use syntax::symbol::LocalInternedString;
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use syntax_pos::Pos;
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use super::{FunctionCx, LocalRef};
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use super::place::PlaceRef;
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use super::operand::OperandRef;
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use super::operand::OperandValue::{Pair, Ref, Immediate};
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/// Used by `FunctionCx::codegen_terminator` for emitting common patterns
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/// e.g., creating a basic block, calling a function, etc.
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struct TerminatorCodegenHelper<'a, 'tcx> {
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bb: &'a mir::BasicBlock,
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terminator: &'a mir::Terminator<'tcx>,
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funclet_bb: Option<mir::BasicBlock>,
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}
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impl<'a, 'tcx> TerminatorCodegenHelper<'a, 'tcx> {
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/// Returns the associated funclet from `FunctionCx::funclets` for the
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/// `funclet_bb` member if it is not `None`.
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fn funclet<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
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&self,
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fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
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) -> Option<&'c Bx::Funclet> {
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match self.funclet_bb {
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Some(funcl) => fx.funclets[funcl].as_ref(),
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None => None,
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}
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}
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fn lltarget<'b, 'c, Bx: BuilderMethods<'b, 'tcx>>(
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&self,
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fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
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target: mir::BasicBlock,
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) -> (Bx::BasicBlock, bool) {
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let span = self.terminator.source_info.span;
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let lltarget = fx.blocks[target];
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let target_funclet = fx.cleanup_kinds[target].funclet_bb(target);
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match (self.funclet_bb, target_funclet) {
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(None, None) => (lltarget, false),
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(Some(f), Some(t_f)) if f == t_f || !base::wants_msvc_seh(fx.cx.tcx().sess) =>
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(lltarget, false),
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// jump *into* cleanup - need a landing pad if GNU
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(None, Some(_)) => (fx.landing_pad_to(target), false),
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(Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", self.terminator),
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(Some(_), Some(_)) => (fx.landing_pad_to(target), true),
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}
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}
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/// Create a basic block.
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fn llblock<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
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&self,
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fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
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target: mir::BasicBlock,
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) -> Bx::BasicBlock {
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let (lltarget, is_cleanupret) = self.lltarget(fx, target);
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if is_cleanupret {
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// MSVC cross-funclet jump - need a trampoline
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debug!("llblock: creating cleanup trampoline for {:?}", target);
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let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target);
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let mut trampoline = fx.new_block(name);
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trampoline.cleanup_ret(self.funclet(fx).unwrap(),
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Some(lltarget));
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trampoline.llbb()
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} else {
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lltarget
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}
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}
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fn funclet_br<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
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&self,
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fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
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bx: &mut Bx,
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target: mir::BasicBlock,
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) {
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let (lltarget, is_cleanupret) = self.lltarget(fx, target);
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if is_cleanupret {
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// micro-optimization: generate a `ret` rather than a jump
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// to a trampoline.
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bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
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} else {
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bx.br(lltarget);
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}
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}
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/// Call `fn_ptr` of `fn_ty` with the arguments `llargs`, the optional
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/// return destination `destination` and the cleanup function `cleanup`.
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fn do_call<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
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&self,
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fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
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bx: &mut Bx,
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fn_ty: FnType<'tcx, Ty<'tcx>>,
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fn_ptr: Bx::Value,
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llargs: &[Bx::Value],
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destination: Option<(ReturnDest<'tcx, Bx::Value>, mir::BasicBlock)>,
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cleanup: Option<mir::BasicBlock>,
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) {
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if let Some(cleanup) = cleanup {
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let ret_bx = if let Some((_, target)) = destination {
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fx.blocks[target]
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} else {
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fx.unreachable_block()
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};
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let invokeret = bx.invoke(fn_ptr,
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&llargs,
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ret_bx,
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self.llblock(fx, cleanup),
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self.funclet(fx));
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bx.apply_attrs_callsite(&fn_ty, invokeret);
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if let Some((ret_dest, target)) = destination {
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let mut ret_bx = fx.build_block(target);
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fx.set_debug_loc(&mut ret_bx, self.terminator.source_info);
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fx.store_return(&mut ret_bx, ret_dest, &fn_ty.ret, invokeret);
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}
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} else {
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let llret = bx.call(fn_ptr, &llargs, self.funclet(fx));
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bx.apply_attrs_callsite(&fn_ty, llret);
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if fx.mir[*self.bb].is_cleanup {
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// Cleanup is always the cold path. Don't inline
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// drop glue. Also, when there is a deeply-nested
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// struct, there are "symmetry" issues that cause
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// exponential inlining - see issue #41696.
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bx.do_not_inline(llret);
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}
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if let Some((ret_dest, target)) = destination {
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fx.store_return(bx, ret_dest, &fn_ty.ret, llret);
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self.funclet_br(fx, bx, target);
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} else {
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bx.unreachable();
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}
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}
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}
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}
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/// Codegen implementations for some terminator variants.
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impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
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/// Generates code for a `Resume` terminator.
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fn codegen_resume_terminator<'b>(
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&mut self,
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helper: TerminatorCodegenHelper<'b, 'tcx>,
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mut bx: Bx,
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) {
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if let Some(funclet) = helper.funclet(self) {
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bx.cleanup_ret(funclet, None);
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} else {
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let slot = self.get_personality_slot(&mut bx);
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let lp0 = slot.project_field(&mut bx, 0);
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let lp0 = bx.load_operand(lp0).immediate();
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let lp1 = slot.project_field(&mut bx, 1);
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let lp1 = bx.load_operand(lp1).immediate();
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slot.storage_dead(&mut bx);
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if !bx.sess().target.target.options.custom_unwind_resume {
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let mut lp = bx.const_undef(self.landing_pad_type());
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lp = bx.insert_value(lp, lp0, 0);
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lp = bx.insert_value(lp, lp1, 1);
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bx.resume(lp);
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} else {
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bx.call(bx.eh_unwind_resume(), &[lp0],
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helper.funclet(self));
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bx.unreachable();
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}
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}
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}
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fn codegen_switchint_terminator<'b>(
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&mut self,
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helper: TerminatorCodegenHelper<'b, 'tcx>,
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mut bx: Bx,
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discr: &mir::Operand<'tcx>,
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switch_ty: Ty<'tcx>,
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values: &Cow<'tcx, [u128]>,
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targets: &Vec<mir::BasicBlock>,
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) {
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let discr = self.codegen_operand(&mut bx, &discr);
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if targets.len() == 2 {
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// If there are two targets, emit br instead of switch
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let lltrue = helper.llblock(self, targets[0]);
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let llfalse = helper.llblock(self, targets[1]);
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if switch_ty == bx.tcx().types.bool {
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// Don't generate trivial icmps when switching on bool
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if let [0] = values[..] {
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bx.cond_br(discr.immediate(), llfalse, lltrue);
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} else {
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assert_eq!(&values[..], &[1]);
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bx.cond_br(discr.immediate(), lltrue, llfalse);
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}
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} else {
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let switch_llty = bx.immediate_backend_type(
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bx.layout_of(switch_ty)
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);
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let llval = bx.const_uint_big(switch_llty, values[0]);
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let cmp = bx.icmp(IntPredicate::IntEQ, discr.immediate(), llval);
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bx.cond_br(cmp, lltrue, llfalse);
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}
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} else {
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let (otherwise, targets) = targets.split_last().unwrap();
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bx.switch(
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discr.immediate(),
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helper.llblock(self, *otherwise),
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values.iter().zip(targets).map(|(&value, target)| {
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(value, helper.llblock(self, *target))
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})
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);
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}
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}
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fn codegen_return_terminator(&mut self, mut bx: Bx) {
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if self.fn_ty.c_variadic {
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match self.va_list_ref {
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Some(va_list) => {
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bx.va_end(va_list.llval);
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}
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None => {
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bug!("C-variadic function must have a `va_list_ref`");
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}
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}
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}
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if self.fn_ty.ret.layout.abi.is_uninhabited() {
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// Functions with uninhabited return values are marked `noreturn`,
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// so we should make sure that we never actually do.
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bx.abort();
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bx.unreachable();
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return;
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}
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let llval = match self.fn_ty.ret.mode {
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PassMode::Ignore(IgnoreMode::Zst) | PassMode::Indirect(..) => {
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bx.ret_void();
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return;
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}
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PassMode::Ignore(IgnoreMode::CVarArgs) => {
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bug!("C-variadic arguments should never be the return type");
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}
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PassMode::Direct(_) | PassMode::Pair(..) => {
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let op =
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self.codegen_consume(&mut bx, &mir::Place::RETURN_PLACE);
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if let Ref(llval, _, align) = op.val {
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bx.load(llval, align)
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} else {
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op.immediate_or_packed_pair(&mut bx)
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}
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}
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PassMode::Cast(cast_ty) => {
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let op = match self.locals[mir::RETURN_PLACE] {
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LocalRef::Operand(Some(op)) => op,
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LocalRef::Operand(None) => bug!("use of return before def"),
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LocalRef::Place(cg_place) => {
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OperandRef {
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val: Ref(cg_place.llval, None, cg_place.align),
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layout: cg_place.layout
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}
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}
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LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
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};
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let llslot = match op.val {
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Immediate(_) | Pair(..) => {
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let scratch =
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PlaceRef::alloca(&mut bx, self.fn_ty.ret.layout, "ret");
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op.val.store(&mut bx, scratch);
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scratch.llval
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}
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Ref(llval, _, align) => {
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assert_eq!(align, op.layout.align.abi,
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"return place is unaligned!");
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llval
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}
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};
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let addr = bx.pointercast(llslot, bx.type_ptr_to(
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bx.cast_backend_type(&cast_ty)
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));
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bx.load(addr, self.fn_ty.ret.layout.align.abi)
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}
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};
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bx.ret(llval);
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}
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fn codegen_drop_terminator<'b>(
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&mut self,
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helper: TerminatorCodegenHelper<'b, 'tcx>,
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mut bx: Bx,
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location: &mir::Place<'tcx>,
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target: mir::BasicBlock,
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unwind: Option<mir::BasicBlock>,
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) {
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let ty = location.ty(self.mir, bx.tcx()).ty;
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let ty = self.monomorphize(&ty);
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let drop_fn = Instance::resolve_drop_in_place(bx.tcx(), ty);
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if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def {
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// we don't actually need to drop anything.
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helper.funclet_br(self, &mut bx, target);
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return
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}
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let place = self.codegen_place(&mut bx, location);
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let (args1, args2);
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let mut args = if let Some(llextra) = place.llextra {
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args2 = [place.llval, llextra];
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&args2[..]
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} else {
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args1 = [place.llval];
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&args1[..]
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};
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let (drop_fn, fn_ty) = match ty.sty {
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ty::Dynamic(..) => {
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let sig = drop_fn.fn_sig(self.cx.tcx());
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let sig = self.cx.tcx().normalize_erasing_late_bound_regions(
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ty::ParamEnv::reveal_all(),
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&sig,
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);
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let fn_ty = FnType::new_vtable(&bx, sig, &[]);
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let vtable = args[1];
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args = &args[..1];
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(meth::DESTRUCTOR.get_fn(&mut bx, vtable, &fn_ty), fn_ty)
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}
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_ => {
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(bx.get_fn(drop_fn),
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FnType::of_instance(&bx, &drop_fn))
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}
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};
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helper.do_call(self, &mut bx, fn_ty, drop_fn, args,
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Some((ReturnDest::Nothing, target)),
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unwind);
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}
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fn codegen_assert_terminator<'b>(
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&mut self,
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helper: TerminatorCodegenHelper<'b, 'tcx>,
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mut bx: Bx,
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terminator: &mir::Terminator<'tcx>,
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cond: &mir::Operand<'tcx>,
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expected: bool,
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msg: &mir::AssertMessage<'tcx>,
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target: mir::BasicBlock,
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cleanup: Option<mir::BasicBlock>,
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) {
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let span = terminator.source_info.span;
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let cond = self.codegen_operand(&mut bx, cond).immediate();
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let mut const_cond = bx.const_to_opt_u128(cond, false).map(|c| c == 1);
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// This case can currently arise only from functions marked
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// with #[rustc_inherit_overflow_checks] and inlined from
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// another crate (mostly core::num generic/#[inline] fns),
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// while the current crate doesn't use overflow checks.
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// NOTE: Unlike binops, negation doesn't have its own
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// checked operation, just a comparison with the minimum
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// value, so we have to check for the assert message.
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if !bx.check_overflow() {
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if let mir::interpret::InterpError::OverflowNeg = *msg {
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const_cond = Some(expected);
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}
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}
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// Don't codegen the panic block if success if known.
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if const_cond == Some(expected) {
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helper.funclet_br(self, &mut bx, target);
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return;
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}
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// Pass the condition through llvm.expect for branch hinting.
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let cond = bx.expect(cond, expected);
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// Create the failure block and the conditional branch to it.
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let lltarget = helper.llblock(self, target);
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let panic_block = self.new_block("panic");
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if expected {
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bx.cond_br(cond, lltarget, panic_block.llbb());
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} else {
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bx.cond_br(cond, panic_block.llbb(), lltarget);
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}
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// After this point, bx is the block for the call to panic.
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bx = panic_block;
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self.set_debug_loc(&mut bx, terminator.source_info);
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// Get the location information.
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let loc = bx.sess().source_map().lookup_char_pos(span.lo());
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let filename = LocalInternedString::intern(&loc.file.name.to_string());
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let line = bx.const_u32(loc.line as u32);
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let col = bx.const_u32(loc.col.to_usize() as u32 + 1);
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|
|
// Put together the arguments to the panic entry point.
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let (lang_item, args) = match *msg {
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InterpError::BoundsCheck { ref len, ref index } => {
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let len = self.codegen_operand(&mut bx, len).immediate();
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let index = self.codegen_operand(&mut bx, index).immediate();
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let file_line_col = bx.static_panic_msg(
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None,
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filename,
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line,
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col,
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"panic_bounds_check_loc",
|
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);
|
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(lang_items::PanicBoundsCheckFnLangItem,
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vec![file_line_col, index, len])
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}
|
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_ => {
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let str = msg.description();
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let msg_str = LocalInternedString::intern(str);
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let msg_file_line_col = bx.static_panic_msg(
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Some(msg_str),
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filename,
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line,
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col,
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"panic_loc",
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);
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(lang_items::PanicFnLangItem,
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vec![msg_file_line_col])
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}
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};
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|
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// Obtain the panic entry point.
|
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let def_id = common::langcall(bx.tcx(), Some(span), "", lang_item);
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let instance = ty::Instance::mono(bx.tcx(), def_id);
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let fn_ty = FnType::of_instance(&bx, &instance);
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let llfn = bx.get_fn(instance);
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|
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// Codegen the actual panic invoke/call.
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helper.do_call(self, &mut bx, fn_ty, llfn, &args, None, cleanup);
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}
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fn codegen_call_terminator<'b>(
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&mut self,
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helper: TerminatorCodegenHelper<'b, 'tcx>,
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mut bx: Bx,
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|
terminator: &mir::Terminator<'tcx>,
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func: &mir::Operand<'tcx>,
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args: &Vec<mir::Operand<'tcx>>,
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destination: &Option<(mir::Place<'tcx>, mir::BasicBlock)>,
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cleanup: Option<mir::BasicBlock>,
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) {
|
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let span = terminator.source_info.span;
|
|
// Create the callee. This is a fn ptr or zero-sized and hence a kind of scalar.
|
|
let callee = self.codegen_operand(&mut bx, func);
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let (instance, mut llfn) = match callee.layout.ty.sty {
|
|
ty::FnDef(def_id, substs) => {
|
|
(Some(ty::Instance::resolve(bx.tcx(),
|
|
ty::ParamEnv::reveal_all(),
|
|
def_id,
|
|
substs).unwrap()),
|
|
None)
|
|
}
|
|
ty::FnPtr(_) => {
|
|
(None, Some(callee.immediate()))
|
|
}
|
|
_ => bug!("{} is not callable", callee.layout.ty),
|
|
};
|
|
let def = instance.map(|i| i.def);
|
|
let sig = callee.layout.ty.fn_sig(bx.tcx());
|
|
let sig = bx.tcx().normalize_erasing_late_bound_regions(
|
|
ty::ParamEnv::reveal_all(),
|
|
&sig,
|
|
);
|
|
let abi = sig.abi;
|
|
|
|
// Handle intrinsics old codegen wants Expr's for, ourselves.
|
|
let intrinsic = match def {
|
|
Some(ty::InstanceDef::Intrinsic(def_id)) =>
|
|
Some(bx.tcx().item_name(def_id).as_str()),
|
|
_ => None
|
|
};
|
|
let intrinsic = intrinsic.as_ref().map(|s| &s[..]);
|
|
|
|
if intrinsic == Some("transmute") {
|
|
if let Some(destination_ref) = destination.as_ref() {
|
|
let &(ref dest, target) = destination_ref;
|
|
self.codegen_transmute(&mut bx, &args[0], dest);
|
|
helper.funclet_br(self, &mut bx, target);
|
|
} else {
|
|
// If we are trying to transmute to an uninhabited type,
|
|
// it is likely there is no allotted destination. In fact,
|
|
// transmuting to an uninhabited type is UB, which means
|
|
// we can do what we like. Here, we declare that transmuting
|
|
// into an uninhabited type is impossible, so anything following
|
|
// it must be unreachable.
|
|
assert_eq!(bx.layout_of(sig.output()).abi, layout::Abi::Uninhabited);
|
|
bx.unreachable();
|
|
}
|
|
return;
|
|
}
|
|
|
|
// The "spoofed" `VaListImpl` added to a C-variadic functions signature
|
|
// should not be included in the `extra_args` calculation.
|
|
let extra_args_start_idx = sig.inputs().len() - if sig.c_variadic { 1 } else { 0 };
|
|
let extra_args = &args[extra_args_start_idx..];
|
|
let extra_args = extra_args.iter().map(|op_arg| {
|
|
let op_ty = op_arg.ty(self.mir, bx.tcx());
|
|
self.monomorphize(&op_ty)
|
|
}).collect::<Vec<_>>();
|
|
|
|
let fn_ty = match def {
|
|
Some(ty::InstanceDef::Virtual(..)) => {
|
|
FnType::new_vtable(&bx, sig, &extra_args)
|
|
}
|
|
Some(ty::InstanceDef::DropGlue(_, None)) => {
|
|
// Empty drop glue; a no-op.
|
|
let &(_, target) = destination.as_ref().unwrap();
|
|
helper.funclet_br(self, &mut bx, target);
|
|
return;
|
|
}
|
|
_ => FnType::new(&bx, sig, &extra_args)
|
|
};
|
|
|
|
// Emit a panic or a no-op for `panic_if_uninhabited`.
|
|
if intrinsic == Some("panic_if_uninhabited") {
|
|
let ty = instance.unwrap().substs.type_at(0);
|
|
let layout = bx.layout_of(ty);
|
|
if layout.abi.is_uninhabited() {
|
|
let loc = bx.sess().source_map().lookup_char_pos(span.lo());
|
|
let filename = LocalInternedString::intern(&loc.file.name.to_string());
|
|
let line = bx.const_u32(loc.line as u32);
|
|
let col = bx.const_u32(loc.col.to_usize() as u32 + 1);
|
|
|
|
let str = format!(
|
|
"Attempted to instantiate uninhabited type {}",
|
|
ty
|
|
);
|
|
let msg_str = LocalInternedString::intern(&str);
|
|
let msg_file_line_col = bx.static_panic_msg(
|
|
Some(msg_str),
|
|
filename,
|
|
line,
|
|
col,
|
|
"panic_loc",
|
|
);
|
|
|
|
// Obtain the panic entry point.
|
|
let def_id =
|
|
common::langcall(bx.tcx(), Some(span), "", lang_items::PanicFnLangItem);
|
|
let instance = ty::Instance::mono(bx.tcx(), def_id);
|
|
let fn_ty = FnType::of_instance(&bx, &instance);
|
|
let llfn = bx.get_fn(instance);
|
|
|
|
// Codegen the actual panic invoke/call.
|
|
helper.do_call(
|
|
self,
|
|
&mut bx,
|
|
fn_ty,
|
|
llfn,
|
|
&[msg_file_line_col],
|
|
destination.as_ref().map(|(_, bb)| (ReturnDest::Nothing, *bb)),
|
|
cleanup,
|
|
);
|
|
} else {
|
|
// a NOP
|
|
helper.funclet_br(self, &mut bx, destination.as_ref().unwrap().1)
|
|
}
|
|
return;
|
|
}
|
|
|
|
// The arguments we'll be passing. Plus one to account for outptr, if used.
|
|
let arg_count = fn_ty.args.len() + fn_ty.ret.is_indirect() as usize;
|
|
let mut llargs = Vec::with_capacity(arg_count);
|
|
|
|
// Prepare the return value destination
|
|
let ret_dest = if let Some((ref dest, _)) = *destination {
|
|
let is_intrinsic = intrinsic.is_some();
|
|
self.make_return_dest(&mut bx, dest, &fn_ty.ret, &mut llargs,
|
|
is_intrinsic)
|
|
} else {
|
|
ReturnDest::Nothing
|
|
};
|
|
|
|
if intrinsic.is_some() && intrinsic != Some("drop_in_place") {
|
|
let dest = match ret_dest {
|
|
_ if fn_ty.ret.is_indirect() => llargs[0],
|
|
ReturnDest::Nothing =>
|
|
bx.const_undef(bx.type_ptr_to(bx.memory_ty(&fn_ty.ret))),
|
|
ReturnDest::IndirectOperand(dst, _) | ReturnDest::Store(dst) =>
|
|
dst.llval,
|
|
ReturnDest::DirectOperand(_) =>
|
|
bug!("Cannot use direct operand with an intrinsic call"),
|
|
};
|
|
|
|
let args: Vec<_> = args.iter().enumerate().map(|(i, arg)| {
|
|
// The indices passed to simd_shuffle* in the
|
|
// third argument must be constant. This is
|
|
// checked by const-qualification, which also
|
|
// promotes any complex rvalues to constants.
|
|
if i == 2 && intrinsic.unwrap().starts_with("simd_shuffle") {
|
|
match *arg {
|
|
// The shuffle array argument is usually not an explicit constant,
|
|
// but specified directly in the code. This means it gets promoted
|
|
// and we can then extract the value by evaluating the promoted.
|
|
mir::Operand::Copy(
|
|
Place::Base(
|
|
PlaceBase::Static(
|
|
box Static { kind: StaticKind::Promoted(promoted), ty }
|
|
)
|
|
)
|
|
) |
|
|
mir::Operand::Move(
|
|
Place::Base(
|
|
PlaceBase::Static(
|
|
box Static { kind: StaticKind::Promoted(promoted), ty }
|
|
)
|
|
)
|
|
) => {
|
|
let param_env = ty::ParamEnv::reveal_all();
|
|
let cid = mir::interpret::GlobalId {
|
|
instance: self.instance,
|
|
promoted: Some(promoted),
|
|
};
|
|
let c = bx.tcx().const_eval(param_env.and(cid));
|
|
let (llval, ty) = self.simd_shuffle_indices(
|
|
&bx,
|
|
terminator.source_info.span,
|
|
ty,
|
|
c,
|
|
);
|
|
return OperandRef {
|
|
val: Immediate(llval),
|
|
layout: bx.layout_of(ty),
|
|
};
|
|
|
|
}
|
|
mir::Operand::Copy(_) |
|
|
mir::Operand::Move(_) => {
|
|
span_bug!(span, "shuffle indices must be constant");
|
|
}
|
|
mir::Operand::Constant(ref constant) => {
|
|
let c = self.eval_mir_constant(constant);
|
|
let (llval, ty) = self.simd_shuffle_indices(
|
|
&bx,
|
|
constant.span,
|
|
constant.ty,
|
|
c,
|
|
);
|
|
return OperandRef {
|
|
val: Immediate(llval),
|
|
layout: bx.layout_of(ty)
|
|
};
|
|
}
|
|
}
|
|
}
|
|
|
|
self.codegen_operand(&mut bx, arg)
|
|
}).collect();
|
|
|
|
|
|
let callee_ty = instance.as_ref().unwrap().ty(bx.tcx());
|
|
bx.codegen_intrinsic_call(callee_ty, &fn_ty, &args, dest,
|
|
terminator.source_info.span);
|
|
|
|
if let ReturnDest::IndirectOperand(dst, _) = ret_dest {
|
|
self.store_return(&mut bx, ret_dest, &fn_ty.ret, dst.llval);
|
|
}
|
|
|
|
if let Some((_, target)) = *destination {
|
|
helper.funclet_br(self, &mut bx, target);
|
|
} else {
|
|
bx.unreachable();
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
// Split the rust-call tupled arguments off.
|
|
let (first_args, untuple) = if abi == Abi::RustCall && !args.is_empty() {
|
|
let (tup, args) = args.split_last().unwrap();
|
|
(args, Some(tup))
|
|
} else {
|
|
(&args[..], None)
|
|
};
|
|
|
|
// Useful determining if the current argument is the "spoofed" `VaListImpl`
|
|
let last_arg_idx = if sig.inputs().is_empty() {
|
|
None
|
|
} else {
|
|
Some(sig.inputs().len() - 1)
|
|
};
|
|
'make_args: for (i, arg) in first_args.iter().enumerate() {
|
|
// If this is a C-variadic function the function signature contains
|
|
// an "spoofed" `VaListImpl`. This argument is ignored, but we need to
|
|
// populate it with a dummy operand so that the users real arguments
|
|
// are not overwritten.
|
|
let i = if sig.c_variadic && last_arg_idx.map(|x| i >= x).unwrap_or(false) {
|
|
if i + 1 < fn_ty.args.len() {
|
|
i + 1
|
|
} else {
|
|
break 'make_args
|
|
}
|
|
} else {
|
|
i
|
|
};
|
|
let mut op = self.codegen_operand(&mut bx, arg);
|
|
|
|
if let (0, Some(ty::InstanceDef::Virtual(_, idx))) = (i, def) {
|
|
if let Pair(..) = op.val {
|
|
// In the case of Rc<Self>, we need to explicitly pass a
|
|
// *mut RcBox<Self> with a Scalar (not ScalarPair) ABI. This is a hack
|
|
// that is understood elsewhere in the compiler as a method on
|
|
// `dyn Trait`.
|
|
// To get a `*mut RcBox<Self>`, we just keep unwrapping newtypes until
|
|
// we get a value of a built-in pointer type
|
|
'descend_newtypes: while !op.layout.ty.is_unsafe_ptr()
|
|
&& !op.layout.ty.is_region_ptr()
|
|
{
|
|
'iter_fields: for i in 0..op.layout.fields.count() {
|
|
let field = op.extract_field(&mut bx, i);
|
|
if !field.layout.is_zst() {
|
|
// we found the one non-zero-sized field that is allowed
|
|
// now find *its* non-zero-sized field, or stop if it's a
|
|
// pointer
|
|
op = field;
|
|
continue 'descend_newtypes
|
|
}
|
|
}
|
|
|
|
span_bug!(span, "receiver has no non-zero-sized fields {:?}", op);
|
|
}
|
|
|
|
// now that we have `*dyn Trait` or `&dyn Trait`, split it up into its
|
|
// data pointer and vtable. Look up the method in the vtable, and pass
|
|
// the data pointer as the first argument
|
|
match op.val {
|
|
Pair(data_ptr, meta) => {
|
|
llfn = Some(meth::VirtualIndex::from_index(idx)
|
|
.get_fn(&mut bx, meta, &fn_ty));
|
|
llargs.push(data_ptr);
|
|
continue 'make_args
|
|
}
|
|
other => bug!("expected a Pair, got {:?}", other),
|
|
}
|
|
} else if let Ref(data_ptr, Some(meta), _) = op.val {
|
|
// by-value dynamic dispatch
|
|
llfn = Some(meth::VirtualIndex::from_index(idx)
|
|
.get_fn(&mut bx, meta, &fn_ty));
|
|
llargs.push(data_ptr);
|
|
continue;
|
|
} else {
|
|
span_bug!(span, "can't codegen a virtual call on {:?}", op);
|
|
}
|
|
}
|
|
|
|
// The callee needs to own the argument memory if we pass it
|
|
// by-ref, so make a local copy of non-immediate constants.
|
|
match (arg, op.val) {
|
|
(&mir::Operand::Copy(_), Ref(_, None, _)) |
|
|
(&mir::Operand::Constant(_), Ref(_, None, _)) => {
|
|
let tmp = PlaceRef::alloca(&mut bx, op.layout, "const");
|
|
op.val.store(&mut bx, tmp);
|
|
op.val = Ref(tmp.llval, None, tmp.align);
|
|
}
|
|
_ => {}
|
|
}
|
|
|
|
self.codegen_argument(&mut bx, op, &mut llargs, &fn_ty.args[i]);
|
|
}
|
|
if let Some(tup) = untuple {
|
|
self.codegen_arguments_untupled(&mut bx, tup, &mut llargs,
|
|
&fn_ty.args[first_args.len()..])
|
|
}
|
|
|
|
let fn_ptr = match (llfn, instance) {
|
|
(Some(llfn), _) => llfn,
|
|
(None, Some(instance)) => bx.get_fn(instance),
|
|
_ => span_bug!(span, "no llfn for call"),
|
|
};
|
|
|
|
helper.do_call(self, &mut bx, fn_ty, fn_ptr, &llargs,
|
|
destination.as_ref().map(|&(_, target)| (ret_dest, target)),
|
|
cleanup);
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
|
|
pub fn codegen_block(
|
|
&mut self,
|
|
bb: mir::BasicBlock,
|
|
) {
|
|
let mut bx = self.build_block(bb);
|
|
let data = &self.mir[bb];
|
|
|
|
debug!("codegen_block({:?}={:?})", bb, data);
|
|
|
|
for statement in &data.statements {
|
|
bx = self.codegen_statement(bx, statement);
|
|
}
|
|
|
|
self.codegen_terminator(bx, bb, data.terminator());
|
|
}
|
|
|
|
fn codegen_terminator(
|
|
&mut self,
|
|
mut bx: Bx,
|
|
bb: mir::BasicBlock,
|
|
terminator: &mir::Terminator<'tcx>
|
|
) {
|
|
debug!("codegen_terminator: {:?}", terminator);
|
|
|
|
// Create the cleanup bundle, if needed.
|
|
let funclet_bb = self.cleanup_kinds[bb].funclet_bb(bb);
|
|
let helper = TerminatorCodegenHelper {
|
|
bb: &bb, terminator, funclet_bb
|
|
};
|
|
|
|
self.set_debug_loc(&mut bx, terminator.source_info);
|
|
match terminator.kind {
|
|
mir::TerminatorKind::Resume => {
|
|
self.codegen_resume_terminator(helper, bx)
|
|
}
|
|
|
|
mir::TerminatorKind::Abort => {
|
|
bx.abort();
|
|
bx.unreachable();
|
|
}
|
|
|
|
mir::TerminatorKind::Goto { target } => {
|
|
helper.funclet_br(self, &mut bx, target);
|
|
}
|
|
|
|
mir::TerminatorKind::SwitchInt {
|
|
ref discr, switch_ty, ref values, ref targets
|
|
} => {
|
|
self.codegen_switchint_terminator(helper, bx, discr, switch_ty,
|
|
values, targets);
|
|
}
|
|
|
|
mir::TerminatorKind::Return => {
|
|
self.codegen_return_terminator(bx);
|
|
}
|
|
|
|
mir::TerminatorKind::Unreachable => {
|
|
bx.unreachable();
|
|
}
|
|
|
|
mir::TerminatorKind::Drop { ref location, target, unwind } => {
|
|
self.codegen_drop_terminator(helper, bx, location, target, unwind);
|
|
}
|
|
|
|
mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => {
|
|
self.codegen_assert_terminator(helper, bx, terminator, cond,
|
|
expected, msg, target, cleanup);
|
|
}
|
|
|
|
mir::TerminatorKind::DropAndReplace { .. } => {
|
|
bug!("undesugared DropAndReplace in codegen: {:?}", terminator);
|
|
}
|
|
|
|
mir::TerminatorKind::Call {
|
|
ref func,
|
|
ref args,
|
|
ref destination,
|
|
cleanup,
|
|
from_hir_call: _
|
|
} => {
|
|
self.codegen_call_terminator(helper, bx, terminator, func,
|
|
args, destination, cleanup);
|
|
}
|
|
mir::TerminatorKind::GeneratorDrop |
|
|
mir::TerminatorKind::Yield { .. } => bug!("generator ops in codegen"),
|
|
mir::TerminatorKind::FalseEdges { .. } |
|
|
mir::TerminatorKind::FalseUnwind { .. } => bug!("borrowck false edges in codegen"),
|
|
}
|
|
}
|
|
|
|
fn codegen_argument(
|
|
&mut self,
|
|
bx: &mut Bx,
|
|
op: OperandRef<'tcx, Bx::Value>,
|
|
llargs: &mut Vec<Bx::Value>,
|
|
arg: &ArgType<'tcx, Ty<'tcx>>
|
|
) {
|
|
// Fill padding with undef value, where applicable.
|
|
if let Some(ty) = arg.pad {
|
|
llargs.push(bx.const_undef(bx.reg_backend_type(&ty)))
|
|
}
|
|
|
|
if arg.is_ignore() {
|
|
return;
|
|
}
|
|
|
|
if let PassMode::Pair(..) = arg.mode {
|
|
match op.val {
|
|
Pair(a, b) => {
|
|
llargs.push(a);
|
|
llargs.push(b);
|
|
return;
|
|
}
|
|
_ => bug!("codegen_argument: {:?} invalid for pair argument", op)
|
|
}
|
|
} else if arg.is_unsized_indirect() {
|
|
match op.val {
|
|
Ref(a, Some(b), _) => {
|
|
llargs.push(a);
|
|
llargs.push(b);
|
|
return;
|
|
}
|
|
_ => bug!("codegen_argument: {:?} invalid for unsized indirect argument", op)
|
|
}
|
|
}
|
|
|
|
// Force by-ref if we have to load through a cast pointer.
|
|
let (mut llval, align, by_ref) = match op.val {
|
|
Immediate(_) | Pair(..) => {
|
|
match arg.mode {
|
|
PassMode::Indirect(..) | PassMode::Cast(_) => {
|
|
let scratch = PlaceRef::alloca(bx, arg.layout, "arg");
|
|
op.val.store(bx, scratch);
|
|
(scratch.llval, scratch.align, true)
|
|
}
|
|
_ => {
|
|
(op.immediate_or_packed_pair(bx), arg.layout.align.abi, false)
|
|
}
|
|
}
|
|
}
|
|
Ref(llval, _, align) => {
|
|
if arg.is_indirect() && align < arg.layout.align.abi {
|
|
// `foo(packed.large_field)`. We can't pass the (unaligned) field directly. I
|
|
// think that ATM (Rust 1.16) we only pass temporaries, but we shouldn't
|
|
// have scary latent bugs around.
|
|
|
|
let scratch = PlaceRef::alloca(bx, arg.layout, "arg");
|
|
base::memcpy_ty(bx, scratch.llval, scratch.align, llval, align,
|
|
op.layout, MemFlags::empty());
|
|
(scratch.llval, scratch.align, true)
|
|
} else {
|
|
(llval, align, true)
|
|
}
|
|
}
|
|
};
|
|
|
|
if by_ref && !arg.is_indirect() {
|
|
// Have to load the argument, maybe while casting it.
|
|
if let PassMode::Cast(ty) = arg.mode {
|
|
let addr = bx.pointercast(llval, bx.type_ptr_to(
|
|
bx.cast_backend_type(&ty))
|
|
);
|
|
llval = bx.load(addr, align.min(arg.layout.align.abi));
|
|
} else {
|
|
// We can't use `PlaceRef::load` here because the argument
|
|
// may have a type we don't treat as immediate, but the ABI
|
|
// used for this call is passing it by-value. In that case,
|
|
// the load would just produce `OperandValue::Ref` instead
|
|
// of the `OperandValue::Immediate` we need for the call.
|
|
llval = bx.load(llval, align);
|
|
if let layout::Abi::Scalar(ref scalar) = arg.layout.abi {
|
|
if scalar.is_bool() {
|
|
bx.range_metadata(llval, 0..2);
|
|
}
|
|
}
|
|
// We store bools as `i8` so we need to truncate to `i1`.
|
|
llval = base::to_immediate(bx, llval, arg.layout);
|
|
}
|
|
}
|
|
|
|
llargs.push(llval);
|
|
}
|
|
|
|
fn codegen_arguments_untupled(
|
|
&mut self,
|
|
bx: &mut Bx,
|
|
operand: &mir::Operand<'tcx>,
|
|
llargs: &mut Vec<Bx::Value>,
|
|
args: &[ArgType<'tcx, Ty<'tcx>>]
|
|
) {
|
|
let tuple = self.codegen_operand(bx, operand);
|
|
|
|
// Handle both by-ref and immediate tuples.
|
|
if let Ref(llval, None, align) = tuple.val {
|
|
let tuple_ptr = PlaceRef::new_sized(llval, tuple.layout, align);
|
|
for i in 0..tuple.layout.fields.count() {
|
|
let field_ptr = tuple_ptr.project_field(bx, i);
|
|
let field = bx.load_operand(field_ptr);
|
|
self.codegen_argument(bx, field, llargs, &args[i]);
|
|
}
|
|
} else if let Ref(_, Some(_), _) = tuple.val {
|
|
bug!("closure arguments must be sized")
|
|
} else {
|
|
// If the tuple is immediate, the elements are as well.
|
|
for i in 0..tuple.layout.fields.count() {
|
|
let op = tuple.extract_field(bx, i);
|
|
self.codegen_argument(bx, op, llargs, &args[i]);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn get_personality_slot(
|
|
&mut self,
|
|
bx: &mut Bx
|
|
) -> PlaceRef<'tcx, Bx::Value> {
|
|
let cx = bx.cx();
|
|
if let Some(slot) = self.personality_slot {
|
|
slot
|
|
} else {
|
|
let layout = cx.layout_of(cx.tcx().intern_tup(&[
|
|
cx.tcx().mk_mut_ptr(cx.tcx().types.u8),
|
|
cx.tcx().types.i32
|
|
]));
|
|
let slot = PlaceRef::alloca(bx, layout, "personalityslot");
|
|
self.personality_slot = Some(slot);
|
|
slot
|
|
}
|
|
}
|
|
|
|
/// Returns the landing-pad wrapper around the given basic block.
|
|
///
|
|
/// No-op in MSVC SEH scheme.
|
|
fn landing_pad_to(
|
|
&mut self,
|
|
target_bb: mir::BasicBlock
|
|
) -> Bx::BasicBlock {
|
|
if let Some(block) = self.landing_pads[target_bb] {
|
|
return block;
|
|
}
|
|
|
|
let block = self.blocks[target_bb];
|
|
let landing_pad = self.landing_pad_uncached(block);
|
|
self.landing_pads[target_bb] = Some(landing_pad);
|
|
landing_pad
|
|
}
|
|
|
|
fn landing_pad_uncached(
|
|
&mut self,
|
|
target_bb: Bx::BasicBlock
|
|
) -> Bx::BasicBlock {
|
|
if base::wants_msvc_seh(self.cx.sess()) {
|
|
span_bug!(self.mir.span, "landing pad was not inserted?")
|
|
}
|
|
|
|
let mut bx = self.new_block("cleanup");
|
|
|
|
let llpersonality = self.cx.eh_personality();
|
|
let llretty = self.landing_pad_type();
|
|
let lp = bx.landing_pad(llretty, llpersonality, 1);
|
|
bx.set_cleanup(lp);
|
|
|
|
let slot = self.get_personality_slot(&mut bx);
|
|
slot.storage_live(&mut bx);
|
|
Pair(bx.extract_value(lp, 0), bx.extract_value(lp, 1)).store(&mut bx, slot);
|
|
|
|
bx.br(target_bb);
|
|
bx.llbb()
|
|
}
|
|
|
|
fn landing_pad_type(&self) -> Bx::Type {
|
|
let cx = self.cx;
|
|
cx.type_struct(&[cx.type_i8p(), cx.type_i32()], false)
|
|
}
|
|
|
|
fn unreachable_block(
|
|
&mut self
|
|
) -> Bx::BasicBlock {
|
|
self.unreachable_block.unwrap_or_else(|| {
|
|
let mut bx = self.new_block("unreachable");
|
|
bx.unreachable();
|
|
self.unreachable_block = Some(bx.llbb());
|
|
bx.llbb()
|
|
})
|
|
}
|
|
|
|
pub fn new_block(&self, name: &str) -> Bx {
|
|
Bx::new_block(self.cx, self.llfn, name)
|
|
}
|
|
|
|
pub fn build_block(
|
|
&self,
|
|
bb: mir::BasicBlock
|
|
) -> Bx {
|
|
let mut bx = Bx::with_cx(self.cx);
|
|
bx.position_at_end(self.blocks[bb]);
|
|
bx
|
|
}
|
|
|
|
fn make_return_dest(
|
|
&mut self,
|
|
bx: &mut Bx,
|
|
dest: &mir::Place<'tcx>,
|
|
fn_ret: &ArgType<'tcx, Ty<'tcx>>,
|
|
llargs: &mut Vec<Bx::Value>, is_intrinsic: bool
|
|
) -> ReturnDest<'tcx, Bx::Value> {
|
|
// If the return is ignored, we can just return a do-nothing `ReturnDest`.
|
|
if fn_ret.is_ignore() {
|
|
return ReturnDest::Nothing;
|
|
}
|
|
let dest = if let mir::Place::Base(mir::PlaceBase::Local(index)) = *dest {
|
|
match self.locals[index] {
|
|
LocalRef::Place(dest) => dest,
|
|
LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
|
|
LocalRef::Operand(None) => {
|
|
// Handle temporary places, specifically `Operand` ones, as
|
|
// they don't have `alloca`s.
|
|
return if fn_ret.is_indirect() {
|
|
// Odd, but possible, case, we have an operand temporary,
|
|
// but the calling convention has an indirect return.
|
|
let tmp = PlaceRef::alloca(bx, fn_ret.layout, "tmp_ret");
|
|
tmp.storage_live(bx);
|
|
llargs.push(tmp.llval);
|
|
ReturnDest::IndirectOperand(tmp, index)
|
|
} else if is_intrinsic {
|
|
// Currently, intrinsics always need a location to store
|
|
// the result, so we create a temporary `alloca` for the
|
|
// result.
|
|
let tmp = PlaceRef::alloca(bx, fn_ret.layout, "tmp_ret");
|
|
tmp.storage_live(bx);
|
|
ReturnDest::IndirectOperand(tmp, index)
|
|
} else {
|
|
ReturnDest::DirectOperand(index)
|
|
};
|
|
}
|
|
LocalRef::Operand(Some(_)) => {
|
|
bug!("place local already assigned to");
|
|
}
|
|
}
|
|
} else {
|
|
self.codegen_place(bx, dest)
|
|
};
|
|
if fn_ret.is_indirect() {
|
|
if dest.align < dest.layout.align.abi {
|
|
// Currently, MIR code generation does not create calls
|
|
// that store directly to fields of packed structs (in
|
|
// fact, the calls it creates write only to temps).
|
|
//
|
|
// If someone changes that, please update this code path
|
|
// to create a temporary.
|
|
span_bug!(self.mir.span, "can't directly store to unaligned value");
|
|
}
|
|
llargs.push(dest.llval);
|
|
ReturnDest::Nothing
|
|
} else {
|
|
ReturnDest::Store(dest)
|
|
}
|
|
}
|
|
|
|
fn codegen_transmute(
|
|
&mut self,
|
|
bx: &mut Bx,
|
|
src: &mir::Operand<'tcx>,
|
|
dst: &mir::Place<'tcx>
|
|
) {
|
|
if let mir::Place::Base(mir::PlaceBase::Local(index)) = *dst {
|
|
match self.locals[index] {
|
|
LocalRef::Place(place) => self.codegen_transmute_into(bx, src, place),
|
|
LocalRef::UnsizedPlace(_) => bug!("transmute must not involve unsized locals"),
|
|
LocalRef::Operand(None) => {
|
|
let dst_layout = bx.layout_of(self.monomorphized_place_ty(dst));
|
|
assert!(!dst_layout.ty.has_erasable_regions());
|
|
let place = PlaceRef::alloca(bx, dst_layout, "transmute_temp");
|
|
place.storage_live(bx);
|
|
self.codegen_transmute_into(bx, src, place);
|
|
let op = bx.load_operand(place);
|
|
place.storage_dead(bx);
|
|
self.locals[index] = LocalRef::Operand(Some(op));
|
|
}
|
|
LocalRef::Operand(Some(op)) => {
|
|
assert!(op.layout.is_zst(),
|
|
"assigning to initialized SSAtemp");
|
|
}
|
|
}
|
|
} else {
|
|
let dst = self.codegen_place(bx, dst);
|
|
self.codegen_transmute_into(bx, src, dst);
|
|
}
|
|
}
|
|
|
|
fn codegen_transmute_into(
|
|
&mut self,
|
|
bx: &mut Bx,
|
|
src: &mir::Operand<'tcx>,
|
|
dst: PlaceRef<'tcx, Bx::Value>
|
|
) {
|
|
let src = self.codegen_operand(bx, src);
|
|
let llty = bx.backend_type(src.layout);
|
|
let cast_ptr = bx.pointercast(dst.llval, bx.type_ptr_to(llty));
|
|
let align = src.layout.align.abi.min(dst.align);
|
|
src.val.store(bx, PlaceRef::new_sized(cast_ptr, src.layout, align));
|
|
}
|
|
|
|
|
|
// Stores the return value of a function call into it's final location.
|
|
fn store_return(
|
|
&mut self,
|
|
bx: &mut Bx,
|
|
dest: ReturnDest<'tcx, Bx::Value>,
|
|
ret_ty: &ArgType<'tcx, Ty<'tcx>>,
|
|
llval: Bx::Value
|
|
) {
|
|
use self::ReturnDest::*;
|
|
|
|
match dest {
|
|
Nothing => (),
|
|
Store(dst) => bx.store_arg_ty(&ret_ty, llval, dst),
|
|
IndirectOperand(tmp, index) => {
|
|
let op = bx.load_operand(tmp);
|
|
tmp.storage_dead(bx);
|
|
self.locals[index] = LocalRef::Operand(Some(op));
|
|
}
|
|
DirectOperand(index) => {
|
|
// If there is a cast, we have to store and reload.
|
|
let op = if let PassMode::Cast(_) = ret_ty.mode {
|
|
let tmp = PlaceRef::alloca(bx, ret_ty.layout, "tmp_ret");
|
|
tmp.storage_live(bx);
|
|
bx.store_arg_ty(&ret_ty, llval, tmp);
|
|
let op = bx.load_operand(tmp);
|
|
tmp.storage_dead(bx);
|
|
op
|
|
} else {
|
|
OperandRef::from_immediate_or_packed_pair(bx, llval, ret_ty.layout)
|
|
};
|
|
self.locals[index] = LocalRef::Operand(Some(op));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
enum ReturnDest<'tcx, V> {
|
|
// Do nothing; the return value is indirect or ignored.
|
|
Nothing,
|
|
// Store the return value to the pointer.
|
|
Store(PlaceRef<'tcx, V>),
|
|
// Store an indirect return value to an operand local place.
|
|
IndirectOperand(PlaceRef<'tcx, V>, mir::Local),
|
|
// Store a direct return value to an operand local place.
|
|
DirectOperand(mir::Local)
|
|
}
|