[llvm-dev] Memory mapping assumptions in RuntimeDyld

[Kai Peter Nacke via llvm-dev]

Hi!

Implementing the Memory::allocateMappedMemory() function on z/OS, I see a 
failure in the AArch64 COFF test case.
The test case has 3 sections. For each section, 
Memory::allocateMappedMemory() is called to reserve memory.
If the distance between the pointers gets too large, then the test case 
fails. It can be reliable produced with
a distance of 1MB between the pointers. An easy way to simulate this is to 
increase the number of memory bytes
requested by 1MB (e.g. adding NumBytes += (1<<20); at begin of the 
method). Then the check if a relocation is correctly
resolved fails.
My current understanding is that the kernel is more or less free to choose 
the address of the mapped memory, so this
situation can arise. Is this true, or do I miss something? Sorry if this 
is a trivial question!

Best regards,
Kai

Kai Nacke
IT Architect

IBM Deutschland GmbH
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