Merge pull request JuliaLang#31431 from NHDaly/nhdaly-llvm-ghost-types

Fix llvm-assertion: don't instantiate 0-sized structs (ghost types)
halleysfifthinc · Mar 25, 2019 · 92a361b · 92a361b
2 parents c46f4bb + 33c15d3
commit 92a361b
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Showing 2 changed files with 18 additions and 5 deletions.
diff --git a/src/intrinsics.cpp b/src/intrinsics.cpp
@@ -600,8 +600,13 @@ static jl_cgval_t emit_pointerref(jl_codectx_t &ctx, jl_cgval_t *argv)
  bool isboxed;
  Type *ptrty = julia_type_to_llvm(ety, &isboxed);
  assert(!isboxed);
- Value *thePtr = emit_unbox(ctx, ptrty->getPointerTo(), e, e.typ);
- return typed_load(ctx, thePtr, im1, ety, tbaa_data, nullptr, true, align_nb);
+ if (!type_is_ghost(ptrty)) {
+ Value *thePtr = emit_unbox(ctx, ptrty->getPointerTo(), e, e.typ);
+ return typed_load(ctx, thePtr, im1, ety, tbaa_data, nullptr, true, align_nb);
+ }
+ else {
+ return ghostValue(ety);
+ }
  }
 }
 
@@ -663,10 +668,12 @@ static jl_cgval_t emit_pointerset(jl_codectx_t &ctx, jl_cgval_t *argv)
  bool isboxed;
  Type *ptrty = julia_type_to_llvm(ety, &isboxed);
  assert(!isboxed);
- thePtr = emit_unbox(ctx, ptrty->getPointerTo(), e, e.typ);
- typed_store(ctx, thePtr, im1, x, ety, tbaa_data, nullptr, nullptr, align_nb);
+ if (!type_is_ghost(ptrty)) {
+ thePtr = emit_unbox(ctx, ptrty->getPointerTo(), e, e.typ);
+ typed_store(ctx, thePtr, im1, x, ety, tbaa_data, nullptr, nullptr, align_nb);
+ }
  }
- return mark_julia_type(ctx, thePtr, false, aty);
+ return e;
 }
 
 static Value *emit_checked_srem_int(jl_codectx_t &ctx, Value *x, Value *den)

diff --git a/test/intrinsics.jl b/test/intrinsics.jl
@@ -100,3 +100,9 @@ let f = Core.Intrinsics.ashr_int
  @test f(Int32(-1), -10) == -1
  @test f(Int32(2), -1) == 0
 end
+
+# issue #29929
+@test unsafe_store!(Ptr{Nothing}(C_NULL), nothing) === Ptr{Nothing}(0)
+@test unsafe_load(Ptr{Nothing}(0)) === nothing
+struct GhostStruct end
+@test unsafe_load(Ptr{GhostStruct}(rand(Int))) === GhostStruct()