Reland "[lldb] Remove non address bits when looking up memory regions"
This reverts commit 0df52296. Additional checks are added to fix the detection of the last memory region in GetMemoryRegions or repeating the "memory region" command when the target has non-address bits. Normally you keep reading from address 0, looking up each region's end address until you get LLDB_INVALID_ADDR as the region end address. (0xffffffffffffffff) This is what the remote will return once you go beyond the last mapped region: [0x0000fffffffdf000-0x0001000000000000) rw- [stack] [0x0001000000000000-0xffffffffffffffff) --- Problem is that when we "fix" the lookup address, we remove some bits from it. On an AArch64 system we have 48 bit virtual addresses, so when we fix the end address of the [stack] region the result is 0. So we loop back to the start. [0x0000fffffffdf000-0x0001000000000000) rw- [stack] [0x0000000000000000-0x0000000000400000) --- To fix this I added an additional check for the last range. If the end address of the region is different once you apply FixDataAddress, we are at the last region. Since the end of the last region will be the last valid mappable address, plus 1. That 1 will be removed by the ABI plugin. The only side effect is that on systems with non-address bits, you won't get that last catch all unmapped region from the max virtual address up to 0xf...f. [0x0000fffff8000000-0x0000fffffffdf000) --- [0x0000fffffffdf000-0x0001000000000000) rw- [stack] <ends here> Though in some way this is more correct because that region is not just unmapped, it's not mappable at all. No extra testing is needed because this is already covered by TestMemoryRegion.py, I simply forgot to run it on system that had both top byte ignore and pointer authentication. This change has been tested on a qemu VM with top byte ignore, memory tagging and pointer authentication enabled. Reviewed By: omjavaid Differential Revision: https://reviews.llvm.org/D115508
Loading
Please sign in to comment