threads: fix semantic error in old Threads.Atomic

JuliaLang · Sep 1, 2021 · aa421ff · aa421ff
1 parent 4598966
commit aa421ff
Show file tree

Hide file tree

Showing 2 changed files with 37 additions and 6 deletions.
diff --git a/base/atomics.jl b/base/atomics.jl
@@ -356,13 +356,13 @@ for typ in atomictypes
  rt = "$lt, $lt*"
  irt = "$ilt, $ilt*"
  @eval getindex(x::Atomic{$typ}) =
- llvmcall($"""
+ GC.@preserve x llvmcall($"""
  %ptr = inttoptr i$WORD_SIZE %0 to $lt*
  %rv = load atomic $rt %ptr acquire, align $(gc_alignment(typ))
  ret $lt %rv
  """, $typ, Tuple{Ptr{$typ}}, unsafe_convert(Ptr{$typ}, x))
  @eval setindex!(x::Atomic{$typ}, v::$typ) =
- llvmcall($"""
+ GC.@preserve x llvmcall($"""
  %ptr = inttoptr i$WORD_SIZE %0 to $lt*
  store atomic $lt %1, $lt* %ptr release, align $(gc_alignment(typ))
  ret void
@@ -371,7 +371,7 @@ for typ in atomictypes
  # Note: atomic_cas! succeeded (i.e. it stored "new") if and only if the result is "cmp"
  if typ <: Integer
  @eval atomic_cas!(x::Atomic{$typ}, cmp::$typ, new::$typ) =
- llvmcall($"""
+ GC.@preserve x llvmcall($"""
  %ptr = inttoptr i$WORD_SIZE %0 to $lt*
  %rs = cmpxchg $lt* %ptr, $lt %1, $lt %2 acq_rel acquire
  %rv = extractvalue { $lt, i1 } %rs, 0
@@ -380,7 +380,7 @@ for typ in atomictypes
  unsafe_convert(Ptr{$typ}, x), cmp, new)
  else
  @eval atomic_cas!(x::Atomic{$typ}, cmp::$typ, new::$typ) =
- llvmcall($"""
+ GC.@preserve x llvmcall($"""
  %iptr = inttoptr i$WORD_SIZE %0 to $ilt*
  %icmp = bitcast $lt %1 to $ilt
  %inew = bitcast $lt %2 to $ilt
@@ -403,15 +403,15 @@ for typ in atomictypes
  if rmwop in arithmetic_ops && !(typ <: ArithmeticTypes) continue end
  if typ <: Integer
  @eval $fn(x::Atomic{$typ}, v::$typ) =
- llvmcall($"""
+ GC.@preserve x llvmcall($"""
  %ptr = inttoptr i$WORD_SIZE %0 to $lt*
  %rv = atomicrmw $rmw $lt* %ptr, $lt %1 acq_rel
  ret $lt %rv
  """, $typ, Tuple{Ptr{$typ}, $typ}, unsafe_convert(Ptr{$typ}, x), v)
  else
  rmwop === :xchg || continue
  @eval $fn(x::Atomic{$typ}, v::$typ) =
- llvmcall($"""
+ GC.@preserve x llvmcall($"""
  %iptr = inttoptr i$WORD_SIZE %0 to $ilt*
  %ival = bitcast $lt %1 to $ilt
  %irv = atomicrmw $rmw $ilt* %iptr, $ilt %ival acq_rel

diff --git a/src/llvm-alloc-opt.cpp b/src/llvm-alloc-opt.cpp
@@ -628,6 +628,21 @@ void Optimizer::checkInst(Instruction *I)
  use_info.hasunknownmem = true;
  return true;
  }
+ if (isa<AtomicCmpXchgInst>(inst) || isa<AtomicRMWInst>(inst)) {
+ // Only store value count
+ if (use->getOperandNo() != isa<AtomicCmpXchgInst>(inst) ? AtomicCmpXchgInst::getPointerOperandIndex() : AtomicRMWInst::getPointerOperandIndex()) {
+ use_info.escaped = true;
+ return false;
+ }
+ use_info.hasload = true;
+ auto storev = isa<AtomicCmpXchgInst>(inst) ? cast<AtomicCmpXchgInst>(inst)->getNewValOperand() : cast<AtomicRMWInst>(inst)->getValOperand();
+ if (cur.offset == UINT32_MAX || !use_info.addMemOp(inst, use->getOperandNo(),
+ cur.offset, storev->getType(),
+ true, *pass.DL))
+ use_info.hasunknownmem = true;
+ use_info.refload = true;
+ return true;
+ }
  if (isa<AddrSpaceCastInst>(inst) || isa<BitCastInst>(inst)) {
  push_inst(inst);
  return true;
@@ -1331,6 +1346,22 @@ void Optimizer::splitOnStack(CallInst *orig_inst)
  store->eraseFromParent();
  return;
  }
+ else if (isa<AtomicCmpXchgInst>(user) || isa<AtomicRMWInst>(user)) {
+ auto slot_idx = find_slot(offset);
+ auto &slot = slots[slot_idx];
+ assert(slot.offset <= offset && slot.offset + slot.size >= offset);
+ IRBuilder<> builder(user);
+ Value *newptr;
+ if (slot.isref) {
+ assert(slot.offset == offset);
+ newptr = slot.slot;
+ }
+ else {
+ Value *Val = isa<AtomicCmpXchgInst>(user) ? cast<AtomicCmpXchgInst>(user)->getNewValOperand() : cast<AtomicRMWInst>(user)->getValOperand();
+ newptr = slot_gep(slot, offset, Val->getType(), builder);
+ }
+ *use = newptr;
+ }
  else if (auto call = dyn_cast<CallInst>(user)) {
  auto callee = call->getCalledOperand();
  assert(callee); // makes it clear for clang analyser that `callee` is not NULL