Summary:
This is the first in a series of patches to eventually add support for TLS relocations to RuntimeDyld. This patch resolves an issue in the current GOT handling, where GOT entries would be reused between object files, which leads to the same situation that necessitates the GOT in the first place, i.e. that the 32-bit offset can not cover all of the address space. Thus this patch makes the GOT object-file-local.
Unfortunately, this still isn't quite enough, because the MemoryManager does not yet guarantee that sections are allocated sufficiently close to each other, even if they belong to the same object file. To address this concern, this patch also adds a small API abstraction on top of the GOT allocation mechanism that will allow (temporarily, until the MemoryManager is improved) using the stub mechanism instead of allocating a different section. The actual switch from separate section to stub mechanism will be part of a follow-on commit, so that it can be easily reverted independently at the appropriate time.
Test Plan: Includes a test case where the GOT of two object files is artificially forced to be apart by several GB.
Reviewers: lhames
Reviewed By: lhames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8813
llvm-svn: 234839
Author: Lang Hames <lhames@gmail.com>
Date: Mon Mar 9 23:51:09 2015 +0000
[Orc][MCJIT][RuntimeDyld] Add header that was accidentally left out of r231724.
Author: Lang Hames <lhames@gmail.com>
Date: Mon Mar 9 23:44:13 2015 +0000
[Orc][MCJIT][RuntimeDyld] Add symbol flags to symbols in RuntimeDyld. Thread the
new types through MCJIT and Orc.
In particular, add a 'weak' flag. When plumbed through RTDyldMemoryManager, this
will allow us to distinguish between weak and strong definitions and find the
right ones during symbol resolution.
llvm-svn: 231731
new types through MCJIT and Orc.
In particular, add a 'weak' flag. When plumbed through RTDyldMemoryManager, this
will allow us to distinguish between weak and strong definitions and find the
right ones during symbol resolution.
llvm-svn: 231724
The syntax of the new builtin is 'section_addr(<filename>, <section-name>)'
(similar to the stub_addr builtin, but without a symbol name). It returns the
base address of the given section in the given object file. This builtin makes
it possible to refer to the contents of sections that cannot contain symbols,
e.g. sections added by the linker itself, like __eh_frame.
llvm-svn: 217010
Add header guards to files that were missing guards. Remove #endif comments
as they don't seem common in LLVM (we can easily add them back if we decide
they're useful)
Changes made by clang-tidy with minor tweaks.
llvm-svn: 215558
full paths for its first argument.
This allows us to remove the annoying sed lines in the test cases, and write
direct references to file names in stub_addr calls (rather than <filename>
placeholders).
llvm-svn: 214211
This patch introduces a 'stub_addr' builtin that can be used to find the address
of the stub for a given (<file>, <section>, <symbol>) tuple. This address can be
used both to verify the contents of stubs (by loading from the returned address)
and to verify references to stubs (by comparing against the returned address).
Example (1) - Verifying stub contents:
Load 8 bytes (assuming a 64-bit target) from the stub for 'x' in the __text
section of f.o, and compare that value against the addres of 'x'.
# rtdyld-check: *{8}(stub_addr(f.o, __text, x) = x
Example (2) - Verifying references to stubs:
Decode the immediate of the instruction at label 'l', and verify that it's
equal to the offset from the next instruction's PC to the stub for 'y' in the
__text section of f.o (i.e. it's the correct PC-rel difference).
# rtdyld-check: decode_operand(l, 4) = stub_addr(f.o, __text, y) - next_pc(l)
l:
movq y@GOTPCREL(%rip), %rax
Since stub inspection requires cooperation with RuntimeDyldImpl this patch
pimpl-ifies RuntimeDyldChecker. Its implementation is moved in to a new class,
RuntimeDyldCheckerImpl, that has access to the definition of RuntimeDyldImpl.
llvm-svn: 213698
Keno Fischer