Solution for memory leak in tblgen

[Anton Korobeynikov]

Why can't you use std::shared_ptr (possibly with custom deleter)
instead of hand-made ref counted class?

On Mon, Jul 28, 2014 at 12:53 PM, wuhui1973 <wuhui1973 at 163.com> wrote:
> Hello Hal, Andy, Nadav, Tom & all:
>
> I have worked out a solution for the memory leak problem in tblgen. This
> memory leak problem is known and deliberatly left by the author for later
> fix.
>
> My solution follows the author's suggestion - using reference counter to
> track the TreePatternNode & TreePattern objects.
>
> Besides, though TreePatternNodes form DAGs, but with TreePattern, they can
> form cyclic graph, the solution also includes
>
> a method to break the cyclic reference. The solution detail please refer to
> the attachment.
>
> I have checked the solution with following actions:
>
> 1> Check tblgen running log, it looks like this:
>
>      llvm[3]: Building X86.td register info implementation with tblgen
>      llvm[3]: Building X86.td instruction information with tblgen
>     1. NumTPNAlloc: 84347, NumTPNRel: 20190            <--- TPN:
> TreePatternNode
>     1. NumTPAlloc: 13441, NumTPRel: 9215                  <--- TP:
> TreePattern
>     2. NumTPNAlloc: 84347, NumTPNRel: 83879
>     2. NumTPAlloc: 13441, NumTPRel: 13271
>     468 TPNs remain, 170 TPs remain                            <--- These
> are cyclic referred nodes
>     Release done
>     3. NumTPNAlloc: 84347, NumTPNRel: 84347
>     3. NumTPAlloc: 13441, NumTPRel: 13441
>
>     Has confirmed all allocated objects get released during the loadbuild
> for all supported targets.
>
> 2> Compare the generated .inc file with those generated by sainty code. Has
> confirmed they all the same.
>
> 3> run "make check" to verify the generated llvm-programs, gets following
> result:
> It contains one error, but the sainty code also gives the same result! I
> will raise the bug report later.
> FAIL: LLVM :: ExecutionEngine/RuntimeDyld/AArch64/MachO_ARM64_relocations.s
> (6206 of 11281)
> ******************** TEST 'LLVM ::
> ExecutionEngine/RuntimeDyld/AArch64/MachO_ARM64_relocations.s' FAILED
> ********************
> Script:
> --
> /sources/new/build_llvm/Debug+Asserts/bin/llvm-mc
> -triple=arm64-apple-ios7.0.0 -code-model=small -relocation-model=pic
> -filetype=obj -o
> /sources/new/build_llvm/test/ExecutionEngine/RuntimeDyld/AArch64/Output/foo.o
> /sources/new/llvm/test/ExecutionEngine/RuntimeDyld/AArch64/MachO_ARM64_relocations.s
> sed
> "s,<filename>,/sources/new/build_llvm/test/ExecutionEngine/RuntimeDyld/AArch64/Output/foo.o,g"
> /sources/new/llvm/test/ExecutionEngine/RuntimeDyld/AArch64/MachO_ARM64_relocations.s
>>
> /sources/new/build_llvm/test/ExecutionEngine/RuntimeDyld/AArch64/Output/foo.s
> /sources/new/build_llvm/Debug+Asserts/bin/llvm-rtdyld
> -triple=arm64-apple-ios7.0.0 -verify
> -check=/sources/new/build_llvm/test/ExecutionEngine/RuntimeDyld/AArch64/Output/foo.s
> /sources/new/build_llvm/test/ExecutionEngine/RuntimeDyld/AArch64/Output/foo.o
> --
> Exit Code: 1
>
> Command Output (stderr):
> --
> Expression 'decode_operand(adrp2, 1) =
> (stub_addr(/sources/new/build_llvm/test/ExecutionEngine/RuntimeDyld/AArch64/Output/foo.o,
> __text, _ptr)[32:12] - adrp2[32:12])' is false: 0xfff00000 != 0x0
> /sources/new/build_llvm/Debug+Asserts/bin/llvm-rtdyld: error: some checks in
> '/sources/new/build_llvm/test/ExecutionEngine/RuntimeDyld/AArch64/Output/foo.s'
> failed
> --
> ********************
> Testing Time: 3155.15s
> ********************
> Failing Tests (1):
>     LLVM :: ExecutionEngine/RuntimeDyld/AArch64/MachO_ARM64_relocations.s
>
>   Expected Passes    : 11144
>   Expected Failures  : 101
>   Unsupported Tests  : 35
>   Unexpected Failures: 1
>
> So I think my solution is correct. Could you review it? Or help to forward
> to someone concerned? Thanks!
>
> Regards
> Hui Wu
>
>
>
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-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University