[GCLowering] correctly handle GC.preserve for demoted objects (JuliaL…

…ang#34241)
halleysfifthinc · Jan 6, 2020 · b807029 · b807029
1 parent 1878343
commit b807029
Show file tree

Hide file tree

Showing 3 changed files with 53 additions and 14 deletions.
diff --git a/src/codegen.cpp b/src/codegen.cpp
@@ -4317,20 +4317,22 @@ static jl_cgval_t emit_expr(jl_codectx_t &ctx, jl_value_t *expr, ssize_t ssaval)
  for (size_t i = 0; i < nargs; ++i) {
  argv[i] = emit_expr(ctx, args[i]);
  }
- size_t nargsboxed = 0;
- Value **vals = (Value**)alloca(sizeof(Value *) * nargs);
+ std::vector<Value*> vals;
  for (size_t i = 0; i < nargs; ++i) {
- if (!argv[i].isboxed) {
- // This is intentionally not an error to allow writing
- // generic code more easily.
- continue;
- } else if (argv[i].constant) {
+ const jl_cgval_t &ai = argv[i];
+ if (ai.constant)
  continue;
+ if (ai.isboxed) {
+ vals.push_back(ai.Vboxed);
+ }
+ else if (!jl_is_pointerfree(ai.typ)) {
+ Type *at = julia_type_to_llvm(ai.typ);
+ vals.push_back(emit_unbox(ctx, at, ai, ai.typ));
  }
- vals[nargsboxed++] = argv[i].Vboxed;
  }
- Value *token = ctx.builder.CreateCall(prepare_call(gc_preserve_begin_func),
- ArrayRef<Value*>(vals, nargsboxed));
+ Value *token = vals.empty()
+ ? (Value*)ConstantTokenNone::get(jl_LLVMContext)
+ : ctx.builder.CreateCall(prepare_call(gc_preserve_begin_func), vals);
  jl_cgval_t tok(token, NULL, false, (jl_value_t*)jl_void_type, NULL);
  return tok;
  }
@@ -4343,7 +4345,8 @@ static jl_cgval_t emit_expr(jl_codectx_t &ctx, jl_value_t *expr, ssize_t ssaval)
  }
  jl_cgval_t token = emit_expr(ctx, args[0]);
  assert(token.V->getType()->isTokenTy());
- ctx.builder.CreateCall(prepare_call(gc_preserve_end_func), {token.V});
+ if (!isa<ConstantTokenNone>(token.V))
+ ctx.builder.CreateCall(prepare_call(gc_preserve_end_func), {token.V});
  return jl_cgval_t((jl_value_t*)jl_void_type);
  }
  else {

diff --git a/src/llvm-late-gc-lowering.cpp b/src/llvm-late-gc-lowering.cpp
@@ -1340,9 +1340,21 @@ State LateLowerGCFrame::LocalScan(Function &F) {
  Value *V = U;
  if (isa<Constant>(V))
  continue;
- int Num = Number(S, V);
- if (Num >= 0)
- args.push_back(Num);
+ if (isa<PointerType>(V->getType())) {
+ if (isSpecialPtr(V->getType())) {
+ int Num = Number(S, V);
+ if (Num >= 0)
+ args.push_back(Num);
+ }
+ } else {
+ std::vector<int> Nums = NumberAll(S, V);
+ for (int Num : Nums) {
+ if (Num < 0)
+ continue;
+ if (Num >= 0)
+ args.push_back(Num);
+ }
+ }
  }
  S.GCPreserves[CI] = args;
  continue;

diff --git a/test/llvmpasses/gcroots.ll b/test/llvmpasses/gcroots.ll
@@ -288,6 +288,30 @@ top:
  ret void
 }
 
+define void @gc_preserve_vec([2 x <2 x %jl_value_t addrspace(10)*>] addrspace(11)* nocapture nonnull readonly dereferenceable(16)) {
+; CHECK-LABEL: @gc_preserve_vec
+; CHECK: %gcframe = alloca %jl_value_t addrspace(10)*, i32 6
+top:
+ %ptls = call %jl_value_t*** @julia.ptls_states()
+ %v = load [2 x <2 x %jl_value_t addrspace(10)*>], [2 x <2 x %jl_value_t addrspace(10)*>] addrspace(11)* %0, align 8
+; CHECK-DAG: [[EXTRACT11:%.*]] = extractvalue [2 x <2 x %jl_value_t addrspace(10)*>] %v, 0
+; CHECK-DAG: [[EXTRACT12:%.*]] = extractvalue [2 x <2 x %jl_value_t addrspace(10)*>] %v, 0
+; CHECK-DAG: [[EXTRACT21:%.*]] = extractvalue [2 x <2 x %jl_value_t addrspace(10)*>] %v, 1
+; CHECK-DAG: [[EXTRACT22:%.*]] = extractvalue [2 x <2 x %jl_value_t addrspace(10)*>] %v, 1
+; CHECK-DAG: [[V11:%.*]] = extractelement <2 x %jl_value_t addrspace(10)*> [[EXTRACT11]], i32 0
+; CHECK-DAG: [[V12:%.*]] = extractelement <2 x %jl_value_t addrspace(10)*> [[EXTRACT12]], i32 1
+; CHECK-DAG: [[V21:%.*]] = extractelement <2 x %jl_value_t addrspace(10)*> [[EXTRACT21]], i32 0
+; CHECK-DAG: [[V22:%.*]] = extractelement <2 x %jl_value_t addrspace(10)*> [[EXTRACT22]], i32 1
+; CHECK-DAG: store %jl_value_t addrspace(10)* [[V11]]
+; CHECK-DAG: store %jl_value_t addrspace(10)* [[V12]]
+; CHECK-DAG: store %jl_value_t addrspace(10)* [[V21]]
+; CHECK-DAG: store %jl_value_t addrspace(10)* [[V22]]
+ %tok = call token (...) @llvm.julia.gc_preserve_begin([2 x <2 x %jl_value_t addrspace(10)*>] %v, i64 addrspace(10)* null, %jl_value_t*** %ptls)
+ call void @jl_safepoint()
+ ret void
+}
+
+
 @gv1 = external global %jl_value_t*
 @gv2 = external global %jl_value_t addrspace(10)*