This repository was archived by the owner on Nov 1, 2020. It is now read-only.
This repository was archived by the owner on Nov 1, 2020. It is now read-only.
build failed on clang5.0 #7619
Description
On 32 bit architectures, size_t is an unsigned 32 bit integer, and therefore the condition can never be true. On clang5.0, this becomes a warning and blocks the build.
/corert/src/Native/gc/unix/cgroup.cpp:440:31: error: comparison of constant 9223372032559808512 with expression of type 'size_t' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
if (physical_memory_limit > 0x7FFFFFFF00000000)
~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~
1 error generated.
Here is the associated code:
// If there's no memory limit specified on the container this
// actually returns 0x7FFFFFFFFFFFF000 (2^63-1 rounded down to
// 4k which is a common page size). So we know we are not
// running in a memory restricted environment.
if (physical_memory_limit > 0x7FFFFFFF00000000)
{
return 0;
}
All we have to do is to figure out what would be returned on an unrestricted 32-bit execution environment. I have tried it on a physical arm32 device, without being inside a Docker container, it returned 0 because FindHierarchyMount finds nothing.
According to this thread, it appears to me that for 32-bits architectures, we should probably check against a different constant, I haven't figured that out yet.