Fix a couple of vasm tests to work around a gcc-8 bug

Reviewed By: alexeyt

Differential Revision: D10406026

fbshipit-source-id: 91576baf443ea83bf97db058df65baa56003376b

hphp/runtime/test/vasm-xls-test.cpp

@@ -50,14 +50,14 @@ template<class T> uint64_t test_const(T val) {
    .sf = x64::abi().sf
  };

  constexpr auto blockSize = 4096;
  auto blockSize = 4096;
  auto code = static_cast<uint8_t*>(mmap(nullptr, blockSize,
                                         PROT_READ | PROT_WRITE | PROT_EXEC,
                                         MAP_PRIVATE | MAP_ANONYMOUS, -1, 0));
  SCOPE_EXIT { munmap(code, blockSize); };

  constexpr auto dataSize = 100;
  constexpr auto codeSize = blockSize - dataSize;
  auto const dataSize = 100;
  auto const codeSize = blockSize - dataSize;
  // None of these tests should use much data.
  auto data_buffer = code + codeSize;

hphp/runtime/test/vasm.cpp

@@ -34,14 +34,14 @@ namespace HPHP { namespace jit {
namespace {
template<typename T, typename Lcodegen, typename Ltest>
void test_function(Lcodegen lcodegen, Ltest ltest) {
  constexpr auto blockSize = 4096;
  auto blockSize = 4096;
  auto code = static_cast<uint8_t*>(mmap(nullptr, blockSize,
                                         PROT_READ | PROT_WRITE | PROT_EXEC,
                                         MAP_PRIVATE | MAP_ANONYMOUS, -1, 0));
  SCOPE_EXIT { munmap(code, blockSize); };

  constexpr auto dataSize = 100;
  constexpr auto codeSize = blockSize - dataSize;
  auto const dataSize = 100;
  auto const codeSize = blockSize - dataSize;
  // None of these tests should use much data.
  auto data_buffer = code + codeSize;