mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2024-11-21 03:13:05 +08:00
Code Issues Packages Projects Releases Wiki Activity

Monkey-patch LLVM code to fix ARM relocation bug.

Browse Source 
Supply a new memory manager for RuntimeDyld, to avoid crashes in
generated code caused by memory placement that can overflow a 32 bit
data type.  This is a drop-in replacement for the
llvm::SectionMemoryManager class in the LLVM library, with Michael
Smith's proposed fix from
https://www.github.com/llvm/llvm-project/pull/71968.

We hereby slurp it into our own source tree, after moving into a new
namespace llvm::backport and making some minor adjustments so that it
can be compiled with older LLVM versions as far back as 12.  It's harder
to make it work on even older LLVM versions, but it doesn't seem likely
that people are really using them so that is not investigated for now.

The problem could also be addressed by switching to JITLink instead of
RuntimeDyld, and that is the LLVM project's recommended solution as
the latter is about to be deprecated.  We'll have to do that soon enough
anyway, and then when the LLVM version support window advances far
enough in a few years we'll be able to delete this code.  Unfortunately
that wouldn't be enough for PostgreSQL today: in most relevant versions
of LLVM, JITLink is missing or incomplete.

Several other projects have already back-ported this fix into their fork
of LLVM, which is a vote of confidence despite the lack of commit into
LLVM as of today.  We don't have our own copy of LLVM so we can't do
exactly what they've done; instead we have a copy of the whole patched
class so we can pass an instance of it to RuntimeDyld.

The LLVM project hasn't chosen to commit the fix yet, and even if it
did, it wouldn't be back-ported into the releases of LLVM that most of
our users care about, so there is not much point in waiting any longer
for that.  If they make further changes and commit it to LLVM 19 or 20,
we'll still need this for older versions, but we may want to
resynchronize our copy and update some comments.

The changes that we've had to make to our copy can be seen by diffing
our SectionMemoryManager.{h,cpp} files against the ones in the tree of
the pull request.  Per the LLVM project's license requirements, a copy
is in SectionMemoryManager.LICENSE.

This should fix the spate of crash reports we've been receiving lately
from users on large memory ARM systems.

Back-patch to all supported releases.

Co-authored-by: Thomas Munro <thomas.munro@gmail.com>
Co-authored-by: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
Reviewed-by: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se> (license aspects)
Reported-by: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
Discussion: https://postgr.es/m/CAO6_Xqr63qj%3DSx7HY6ZiiQ6R_JbX%2B-p6sTPwDYwTWZjUmjsYBg%40mail.gmail.com
This commit is contained in:
Thomas Munro 2024-11-06 22:04:44 +13:00
parent 925b3aa857
commit ee67b73f59
11 changed files with 985 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
src/backend/jit/llvm/Makefile
View File

@ -47,7 +47,8 @@ OBJS += \
llvmjit.o \
llvmjit_error.o \
llvmjit_inline.o \
llvmjit_wrap.o
llvmjit_wrap.o \
SectionMemoryManager.o
# Code generation
OBJS += \

279
src/backend/jit/llvm/SectionMemoryManager.LICENSE Normal file
View File

@ -0,0 +1,279 @@
==============================================================================
The LLVM Project is under the Apache License v2.0 with LLVM Exceptions:
==============================================================================
Apache License
Version 2.0, January 2004
http://www.apache.org/licenses/
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
1. Definitions.
"License" shall mean the terms and conditions for use, reproduction,
and distribution as defined by Sections 1 through 9 of this document.
"Licensor" shall mean the copyright owner or entity authorized by
the copyright owner that is granting the License.
"Legal Entity" shall mean the union of the acting entity and all
other entities that control, are controlled by, or are under common
control with that entity. For the purposes of this definition,
"control" means (i) the power, direct or indirect, to cause the
direction or management of such entity, whether by contract or
otherwise, or (ii) ownership of fifty percent (50%) or more of the
outstanding shares, or (iii) beneficial ownership of such entity.
"You" (or "Your") shall mean an individual or Legal Entity
exercising permissions granted by this License.
"Source" form shall mean the preferred form for making modifications,
including but not limited to software source code, documentation
source, and configuration files.
"Object" form shall mean any form resulting from mechanical
transformation or translation of a Source form, including but
not limited to compiled object code, generated documentation,
and conversions to other media types.
"Work" shall mean the work of authorship, whether in Source or
Object form, made available under the License, as indicated by a
copyright notice that is included in or attached to the work
(an example is provided in the Appendix below).
"Derivative Works" shall mean any work, whether in Source or Object
form, that is based on (or derived from) the Work and for which the
editorial revisions, annotations, elaborations, or other modifications
represent, as a whole, an original work of authorship. For the purposes
of this License, Derivative Works shall not include works that remain
separable from, or merely link (or bind by name) to the interfaces of,
the Work and Derivative Works thereof.
"Contribution" shall mean any work of authorship, including
the original version of the Work and any modifications or additions
to that Work or Derivative Works thereof, that is intentionally
submitted to Licensor for inclusion in the Work by the copyright owner
or by an individual or Legal Entity authorized to submit on behalf of
the copyright owner. For the purposes of this definition, "submitted"
means any form of electronic, verbal, or written communication sent
to the Licensor or its representatives, including but not limited to
communication on electronic mailing lists, source code control systems,
and issue tracking systems that are managed by, or on behalf of, the
Licensor for the purpose of discussing and improving the Work, but
excluding communication that is conspicuously marked or otherwise
designated in writing by the copyright owner as "Not a Contribution."
"Contributor" shall mean Licensor and any individual or Legal Entity
on behalf of whom a Contribution has been received by Licensor and
subsequently incorporated within the Work.
2. Grant of Copyright License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
copyright license to reproduce, prepare Derivative Works of,
publicly display, publicly perform, sublicense, and distribute the
Work and such Derivative Works in Source or Object form.
3. Grant of Patent License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
(except as stated in this section) patent license to make, have made,
use, offer to sell, sell, import, and otherwise transfer the Work,
where such license applies only to those patent claims licensable
by such Contributor that are necessarily infringed by their
Contribution(s) alone or by combination of their Contribution(s)
with the Work to which such Contribution(s) was submitted. If You
institute patent litigation against any entity (including a
cross-claim or counterclaim in a lawsuit) alleging that the Work
or a Contribution incorporated within the Work constitutes direct
or contributory patent infringement, then any patent licenses
granted to You under this License for that Work shall terminate
as of the date such litigation is filed.
4. Redistribution. You may reproduce and distribute copies of the
Work or Derivative Works thereof in any medium, with or without
modifications, and in Source or Object form, provided that You
meet the following conditions:
(a) You must give any other recipients of the Work or
Derivative Works a copy of this License; and
(b) You must cause any modified files to carry prominent notices
stating that You changed the files; and
(c) You must retain, in the Source form of any Derivative Works
that You distribute, all copyright, patent, trademark, and
attribution notices from the Source form of the Work,
excluding those notices that do not pertain to any part of
the Derivative Works; and
(d) If the Work includes a "NOTICE" text file as part of its
distribution, then any Derivative Works that You distribute must
include a readable copy of the attribution notices contained
within such NOTICE file, excluding those notices that do not
pertain to any part of the Derivative Works, in at least one
of the following places: within a NOTICE text file distributed
as part of the Derivative Works; within the Source form or
documentation, if provided along with the Derivative Works; or,
within a display generated by the Derivative Works, if and
wherever such third-party notices normally appear. The contents
of the NOTICE file are for informational purposes only and
do not modify the License. You may add Your own attribution
notices within Derivative Works that You distribute, alongside
or as an addendum to the NOTICE text from the Work, provided
that such additional attribution notices cannot be construed
as modifying the License.
You may add Your own copyright statement to Your modifications and
may provide additional or different license terms and conditions
for use, reproduction, or distribution of Your modifications, or
for any such Derivative Works as a whole, provided Your use,
reproduction, and distribution of the Work otherwise complies with
the conditions stated in this License.
5. Submission of Contributions. Unless You explicitly state otherwise,
any Contribution intentionally submitted for inclusion in the Work
by You to the Licensor shall be under the terms and conditions of
this License, without any additional terms or conditions.
Notwithstanding the above, nothing herein shall supersede or modify
the terms of any separate license agreement you may have executed
with Licensor regarding such Contributions.
6. Trademarks. This License does not grant permission to use the trade
names, trademarks, service marks, or product names of the Licensor,
except as required for reasonable and customary use in describing the
origin of the Work and reproducing the content of the NOTICE file.
7. Disclaimer of Warranty. Unless required by applicable law or
agreed to in writing, Licensor provides the Work (and each
Contributor provides its Contributions) on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied, including, without limitation, any warranties or conditions
of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
PARTICULAR PURPOSE. You are solely responsible for determining the
appropriateness of using or redistributing the Work and assume any
risks associated with Your exercise of permissions under this License.
8. Limitation of Liability. In no event and under no legal theory,
whether in tort (including negligence), contract, or otherwise,
unless required by applicable law (such as deliberate and grossly
negligent acts) or agreed to in writing, shall any Contributor be
liable to You for damages, including any direct, indirect, special,
incidental, or consequential damages of any character arising as a
result of this License or out of the use or inability to use the
Work (including but not limited to damages for loss of goodwill,
work stoppage, computer failure or malfunction, or any and all
other commercial damages or losses), even if such Contributor
has been advised of the possibility of such damages.
9. Accepting Warranty or Additional Liability. While redistributing
the Work or Derivative Works thereof, You may choose to offer,
and charge a fee for, acceptance of support, warranty, indemnity,
or other liability obligations and/or rights consistent with this
License. However, in accepting such obligations, You may act only
on Your own behalf and on Your sole responsibility, not on behalf
of any other Contributor, and only if You agree to indemnify,
defend, and hold each Contributor harmless for any liability
incurred by, or claims asserted against, such Contributor by reason
of your accepting any such warranty or additional liability.
END OF TERMS AND CONDITIONS
APPENDIX: How to apply the Apache License to your work.
To apply the Apache License to your work, attach the following
boilerplate notice, with the fields enclosed by brackets "[]"
replaced with your own identifying information. (Don't include
the brackets!) The text should be enclosed in the appropriate
comment syntax for the file format. We also recommend that a
file or class name and description of purpose be included on the
same "printed page" as the copyright notice for easier
identification within third-party archives.
Copyright [yyyy] [name of copyright owner]
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
---- LLVM Exceptions to the Apache 2.0 License ----
As an exception, if, as a result of your compiling your source code, portions
of this Software are embedded into an Object form of such source code, you
may redistribute such embedded portions in such Object form without complying
with the conditions of Sections 4(a), 4(b) and 4(d) of the License.
In addition, if you combine or link compiled forms of this Software with
software that is licensed under the GPLv2 ("Combined Software") and if a
court of competent jurisdiction determines that the patent provision (Section
3), the indemnity provision (Section 9) or other Section of the License
conflicts with the conditions of the GPLv2, you may retroactively and
prospectively choose to deem waived or otherwise exclude such Section(s) of
the License, but only in their entirety and only with respect to the Combined
Software.
==============================================================================
Software from third parties included in the LLVM Project:
==============================================================================
The LLVM Project contains third party software which is under different license
terms. All such code will be identified clearly using at least one of two
mechanisms:
1) It will be in a separate directory tree with its own `LICENSE.txt` or
`LICENSE` file at the top containing the specific license and restrictions
which apply to that software, or
2) It will contain specific license and restriction terms at the top of every
file.
==============================================================================
Legacy LLVM License (https://llvm.org/docs/DeveloperPolicy.html#legacy):
==============================================================================
University of Illinois/NCSA
Open Source License
Copyright (c) 2003-2019 University of Illinois at Urbana-Champaign.
All rights reserved.
Developed by:
LLVM Team
University of Illinois at Urbana-Champaign
http://llvm.org
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal with
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimers.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimers in the
documentation and/or other materials provided with the distribution.
* Neither the names of the LLVM Team, University of Illinois at
Urbana-Champaign, nor the names of its contributors may be used to
endorse or promote products derived from this Software without specific
prior written permission.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
SOFTWARE.

412
src/backend/jit/llvm/SectionMemoryManager.cpp Normal file
View File

@ -0,0 +1,412 @@
/*
* This file is from https://github.com/llvm/llvm-project/pull/71968
* with minor modifications to avoid name clash and work with older
* LLVM versions. The llvm::backport::SectionMemoryManager class is a
* drop-in replacement for llvm::SectionMemoryManager, for use with
* llvm::RuntimeDyld. It fixes a memory layout bug on large memory
* ARM systems (see pull request for details). If the LLVM project
* eventually commits the change, we may need to resynchronize our
* copy with any further modifications, but they would be unlikely to
* backport it into the LLVM versions that we target so we would still
* need this copy.
*
* In the future we will switch to using JITLink instead of
* RuntimeDyld where possible, and later remove this code (.cpp, .h,
* .LICENSE) after all LLVM versions that we target allow it.
*
* This file is a modified copy of a part of the LLVM source code that
* we would normally access from the LLVM library. It is therefore
* covered by the license at https://llvm.org/LICENSE.txt, reproduced
* verbatim in SectionMemoryManager.LICENSE in fulfillment of clause
* 4a. The bugfix changes from the pull request are also covered, per
* clause 5.
*/
//===- SectionMemoryManager.cpp - Memory manager for MCJIT/RtDyld *- C++ -*-==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the section-based memory manager used by the MCJIT
// execution engine and RuntimeDyld
//
//===----------------------------------------------------------------------===//
#include "jit/llvmjit_backport.h"
#ifdef USE_LLVM_BACKPORT_SECTION_MEMORY_MANAGER
#include "jit/SectionMemoryManager.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Process.h"
namespace llvm {
namespace backport {
bool SectionMemoryManager::hasSpace(const MemoryGroup &MemGroup,
uintptr_t Size) const {
for (const FreeMemBlock &FreeMB : MemGroup.FreeMem) {
if (FreeMB.Free.allocatedSize() >= Size)
return true;
}
return false;
}
#if LLVM_VERSION_MAJOR < 16
void SectionMemoryManager::reserveAllocationSpace(uintptr_t CodeSize,
uint32_t CodeAlign_i,
uintptr_t RODataSize,
uint32_t RODataAlign_i,
uintptr_t RWDataSize,
uint32_t RWDataAlign_i) {
Align CodeAlign(CodeAlign_i);
Align RODataAlign(RODataAlign_i);
Align RWDataAlign(RWDataAlign_i);
#else
void SectionMemoryManager::reserveAllocationSpace(
uintptr_t CodeSize, Align CodeAlign, uintptr_t RODataSize,
Align RODataAlign, uintptr_t RWDataSize, Align RWDataAlign) {
#endif
if (CodeSize == 0 && RODataSize == 0 && RWDataSize == 0)
return;
static const size_t PageSize = sys::Process::getPageSizeEstimate();
// Code alignment needs to be at least the stub alignment - however, we
// don't have an easy way to get that here so as a workaround, we assume
// it's 8, which is the largest value I observed across all platforms.
constexpr uint64_t StubAlign = 8;
CodeAlign = Align(std::max(CodeAlign.value(), StubAlign));
RODataAlign = Align(std::max(RODataAlign.value(), StubAlign));
RWDataAlign = Align(std::max(RWDataAlign.value(), StubAlign));
// Get space required for each section. Use the same calculation as
// allocateSection because we need to be able to satisfy it.
uint64_t RequiredCodeSize = alignTo(CodeSize, CodeAlign) + CodeAlign.value();
uint64_t RequiredRODataSize =
alignTo(RODataSize, RODataAlign) + RODataAlign.value();
uint64_t RequiredRWDataSize =
alignTo(RWDataSize, RWDataAlign) + RWDataAlign.value();
if (hasSpace(CodeMem, RequiredCodeSize) &&
hasSpace(RODataMem, RequiredRODataSize) &&
hasSpace(RWDataMem, RequiredRWDataSize)) {
// Sufficient space in contiguous block already available.
return;
}
// MemoryManager does not have functions for releasing memory after it's
// allocated. Normally it tries to use any excess blocks that were allocated
// due to page alignment, but if we have insufficient free memory for the
// request this can lead to allocating disparate memory that can violate the
// ARM ABI. Clear free memory so only the new allocations are used, but do
// not release allocated memory as it may still be in-use.
CodeMem.FreeMem.clear();
RODataMem.FreeMem.clear();
RWDataMem.FreeMem.clear();
// Round up to the nearest page size. Blocks must be page-aligned.
RequiredCodeSize = alignTo(RequiredCodeSize, PageSize);
RequiredRODataSize = alignTo(RequiredRODataSize, PageSize);
RequiredRWDataSize = alignTo(RequiredRWDataSize, PageSize);
uint64_t RequiredSize =
RequiredCodeSize + RequiredRODataSize + RequiredRWDataSize;
std::error_code ec;
sys::MemoryBlock MB = MMapper->allocateMappedMemory(
AllocationPurpose::RWData, RequiredSize, nullptr,
sys::Memory::MF_READ | sys::Memory::MF_WRITE, ec);
if (ec) {
return;
}
// CodeMem will arbitrarily own this MemoryBlock to handle cleanup.
CodeMem.AllocatedMem.push_back(MB);
uintptr_t Addr = (uintptr_t)MB.base();
FreeMemBlock FreeMB;
FreeMB.PendingPrefixIndex = (unsigned)-1;
if (CodeSize > 0) {
assert(isAddrAligned(CodeAlign, (void *)Addr));
FreeMB.Free = sys::MemoryBlock((void *)Addr, RequiredCodeSize);
CodeMem.FreeMem.push_back(FreeMB);
Addr += RequiredCodeSize;
}
if (RODataSize > 0) {
assert(isAddrAligned(RODataAlign, (void *)Addr));
FreeMB.Free = sys::MemoryBlock((void *)Addr, RequiredRODataSize);
RODataMem.FreeMem.push_back(FreeMB);
Addr += RequiredRODataSize;
}
if (RWDataSize > 0) {
assert(isAddrAligned(RWDataAlign, (void *)Addr));
FreeMB.Free = sys::MemoryBlock((void *)Addr, RequiredRWDataSize);
RWDataMem.FreeMem.push_back(FreeMB);
}
}
uint8_t *SectionMemoryManager::allocateDataSection(uintptr_t Size,
unsigned Alignment,
unsigned SectionID,
StringRef SectionName,
bool IsReadOnly) {
if (IsReadOnly)
return allocateSection(SectionMemoryManager::AllocationPurpose::ROData,
Size, Alignment);
return allocateSection(SectionMemoryManager::AllocationPurpose::RWData, Size,
Alignment);
}
uint8_t *SectionMemoryManager::allocateCodeSection(uintptr_t Size,
unsigned Alignment,
unsigned SectionID,
StringRef SectionName) {
return allocateSection(SectionMemoryManager::AllocationPurpose::Code, Size,
Alignment);
}
uint8_t *SectionMemoryManager::allocateSection(
SectionMemoryManager::AllocationPurpose Purpose, uintptr_t Size,
unsigned Alignment) {
if (!Alignment)
Alignment = 16;
assert(!(Alignment & (Alignment - 1)) && "Alignment must be a power of two.");
uintptr_t RequiredSize = Alignment * ((Size + Alignment - 1) / Alignment + 1);
uintptr_t Addr = 0;
MemoryGroup &MemGroup = [&]() -> MemoryGroup & {
switch (Purpose) {
case AllocationPurpose::Code:
return CodeMem;
case AllocationPurpose::ROData:
return RODataMem;
case AllocationPurpose::RWData:
return RWDataMem;
}
llvm_unreachable("Unknown SectionMemoryManager::AllocationPurpose");
}();
// Look in the list of free memory regions and use a block there if one
// is available.
for (FreeMemBlock &FreeMB : MemGroup.FreeMem) {
if (FreeMB.Free.allocatedSize() >= RequiredSize) {
Addr = (uintptr_t)FreeMB.Free.base();
uintptr_t EndOfBlock = Addr + FreeMB.Free.allocatedSize();
// Align the address.
Addr = (Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1);
if (FreeMB.PendingPrefixIndex == (unsigned)-1) {
// The part of the block we're giving out to the user is now pending
MemGroup.PendingMem.push_back(sys::MemoryBlock((void *)Addr, Size));
// Remember this pending block, such that future allocations can just
// modify it rather than creating a new one
FreeMB.PendingPrefixIndex = MemGroup.PendingMem.size() - 1;
} else {
sys::MemoryBlock &PendingMB =
MemGroup.PendingMem[FreeMB.PendingPrefixIndex];
PendingMB = sys::MemoryBlock(PendingMB.base(),
Addr + Size - (uintptr_t)PendingMB.base());
}
// Remember how much free space is now left in this block
FreeMB.Free =
sys::MemoryBlock((void *)(Addr + Size), EndOfBlock - Addr - Size);
return (uint8_t *)Addr;
}
}
// No pre-allocated free block was large enough. Allocate a new memory region.
// Note that all sections get allocated as read-write. The permissions will
// be updated later based on memory group.
//
// FIXME: It would be useful to define a default allocation size (or add
// it as a constructor parameter) to minimize the number of allocations.
//
// FIXME: Initialize the Near member for each memory group to avoid
// interleaving.
std::error_code ec;
sys::MemoryBlock MB = MMapper->allocateMappedMemory(
Purpose, RequiredSize, &MemGroup.Near,
sys::Memory::MF_READ | sys::Memory::MF_WRITE, ec);
if (ec) {
// FIXME: Add error propagation to the interface.
return nullptr;
}
// Save this address as the basis for our next request
MemGroup.Near = MB;
// Copy the address to all the other groups, if they have not
// been initialized.
if (CodeMem.Near.base() == nullptr)
CodeMem.Near = MB;
if (RODataMem.Near.base() == nullptr)
RODataMem.Near = MB;
if (RWDataMem.Near.base() == nullptr)
RWDataMem.Near = MB;
// Remember that we allocated this memory
MemGroup.AllocatedMem.push_back(MB);
Addr = (uintptr_t)MB.base();
uintptr_t EndOfBlock = Addr + MB.allocatedSize();
// Align the address.
Addr = (Addr + Alignment - 1) & ~(uintptr_t)(Alignment - 1);
// The part of the block we're giving out to the user is now pending
MemGroup.PendingMem.push_back(sys::MemoryBlock((void *)Addr, Size));
// The allocateMappedMemory may allocate much more memory than we need. In
// this case, we store the unused memory as a free memory block.
unsigned FreeSize = EndOfBlock - Addr - Size;
if (FreeSize > 16) {
FreeMemBlock FreeMB;
FreeMB.Free = sys::MemoryBlock((void *)(Addr + Size), FreeSize);
FreeMB.PendingPrefixIndex = (unsigned)-1;
MemGroup.FreeMem.push_back(FreeMB);
}
// Return aligned address
return (uint8_t *)Addr;
}
bool SectionMemoryManager::finalizeMemory(std::string *ErrMsg) {
// FIXME: Should in-progress permissions be reverted if an error occurs?
std::error_code ec;
// Make code memory executable.
ec = applyMemoryGroupPermissions(CodeMem,
sys::Memory::MF_READ | sys::Memory::MF_EXEC);
if (ec) {
if (ErrMsg) {
*ErrMsg = ec.message();
}
return true;
}
// Make read-only data memory read-only.
ec = applyMemoryGroupPermissions(RODataMem, sys::Memory::MF_READ);
if (ec) {
if (ErrMsg) {
*ErrMsg = ec.message();
}
return true;
}
// Read-write data memory already has the correct permissions
// Some platforms with separate data cache and instruction cache require
// explicit cache flush, otherwise JIT code manipulations (like resolved
// relocations) will get to the data cache but not to the instruction cache.
invalidateInstructionCache();
return false;
}
static sys::MemoryBlock trimBlockToPageSize(sys::MemoryBlock M) {
static const size_t PageSize = sys::Process::getPageSizeEstimate();
size_t StartOverlap =
(PageSize - ((uintptr_t)M.base() % PageSize)) % PageSize;
size_t TrimmedSize = M.allocatedSize();
TrimmedSize -= StartOverlap;
TrimmedSize -= TrimmedSize % PageSize;
sys::MemoryBlock Trimmed((void *)((uintptr_t)M.base() + StartOverlap),
TrimmedSize);
assert(((uintptr_t)Trimmed.base() % PageSize) == 0);
assert((Trimmed.allocatedSize() % PageSize) == 0);
assert(M.base() <= Trimmed.base() &&
Trimmed.allocatedSize() <= M.allocatedSize());
return Trimmed;
}
std::error_code
SectionMemoryManager::applyMemoryGroupPermissions(MemoryGroup &MemGroup,
unsigned Permissions) {
for (sys::MemoryBlock &MB : MemGroup.PendingMem)
if (std::error_code EC = MMapper->protectMappedMemory(MB, Permissions))
return EC;
MemGroup.PendingMem.clear();
// Now go through free blocks and trim any of them that don't span the entire
// page because one of the pending blocks may have overlapped it.
for (FreeMemBlock &FreeMB : MemGroup.FreeMem) {
FreeMB.Free = trimBlockToPageSize(FreeMB.Free);
// We cleared the PendingMem list, so all these pointers are now invalid
FreeMB.PendingPrefixIndex = (unsigned)-1;
}
// Remove all blocks which are now empty
erase_if(MemGroup.FreeMem, [](FreeMemBlock &FreeMB) {
return FreeMB.Free.allocatedSize() == 0;
});
return std::error_code();
}
void SectionMemoryManager::invalidateInstructionCache() {
for (sys::MemoryBlock &Block : CodeMem.PendingMem)
sys::Memory::InvalidateInstructionCache(Block.base(),
Block.allocatedSize());
}
SectionMemoryManager::~SectionMemoryManager() {
for (MemoryGroup *Group : {&CodeMem, &RWDataMem, &RODataMem}) {
for (sys::MemoryBlock &Block : Group->AllocatedMem)
MMapper->releaseMappedMemory(Block);
}
}
SectionMemoryManager::MemoryMapper::~MemoryMapper() = default;
void SectionMemoryManager::anchor() {}
namespace {
// Trivial implementation of SectionMemoryManager::MemoryMapper that just calls
// into sys::Memory.
class DefaultMMapper final : public SectionMemoryManager::MemoryMapper {
public:
sys::MemoryBlock
allocateMappedMemory(SectionMemoryManager::AllocationPurpose Purpose,
size_t NumBytes, const sys::MemoryBlock *const NearBlock,
unsigned Flags, std::error_code &EC) override {
return sys::Memory::allocateMappedMemory(NumBytes, NearBlock, Flags, EC);
}
std::error_code protectMappedMemory(const sys::MemoryBlock &Block,
unsigned Flags) override {
return sys::Memory::protectMappedMemory(Block, Flags);
}
std::error_code releaseMappedMemory(sys::MemoryBlock &M) override {
return sys::Memory::releaseMappedMemory(M);
}
};
} // namespace
SectionMemoryManager::SectionMemoryManager(MemoryMapper *UnownedMM,
bool ReserveAlloc)
: MMapper(UnownedMM), OwnedMMapper(nullptr),
ReserveAllocation(ReserveAlloc) {
if (!MMapper) {
OwnedMMapper = std::make_unique<DefaultMMapper>();
MMapper = OwnedMMapper.get();
}
}
} // namespace backport
} // namespace llvm
#endif

7
src/backend/jit/llvm/llvmjit.c
View File

@ -40,6 +40,7 @@
#endif
#include "jit/llvmjit.h"
#include "jit/llvmjit_backport.h"
#include "jit/llvmjit_emit.h"
#include "miscadmin.h"
#include "portability/instr_time.h"
@ -1316,8 +1317,14 @@ llvm_log_jit_error(void *ctx, LLVMErrorRef error)
static LLVMOrcObjectLayerRef
llvm_create_object_layer(void *Ctx, LLVMOrcExecutionSessionRef ES, const char *Triple)
{
#ifdef USE_LLVM_BACKPORT_SECTION_MEMORY_MANAGER
LLVMOrcObjectLayerRef objlayer =
LLVMOrcCreateRTDyldObjectLinkingLayerWithSafeSectionMemoryManager(ES);
#else
LLVMOrcObjectLayerRef objlayer =
LLVMOrcCreateRTDyldObjectLinkingLayerWithSectionMemoryManager(ES);
#endif
#if defined(HAVE_DECL_LLVMCREATEGDBREGISTRATIONLISTENER) && HAVE_DECL_LLVMCREATEGDBREGISTRATIONLISTENER
if (jit_debugging_support)

20
src/backend/jit/llvm/llvmjit_wrap.cpp
View File

@ -33,6 +33,14 @@ extern "C"
#endif
#include "jit/llvmjit.h"
#include "jit/llvmjit_backport.h"
#ifdef USE_LLVM_BACKPORT_SECTION_MEMORY_MANAGER
#include <llvm/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.h>
#include <llvm/ExecutionEngine/SectionMemoryManager.h>
#include "jit/SectionMemoryManager.h"
#include <llvm/Support/CBindingWrapping.h>
#endif
/*
@ -102,3 +110,15 @@ LLVMGlobalGetValueType(LLVMValueRef g)
return llvm::wrap(llvm::unwrap<llvm::GlobalValue>(g)->getValueType());
}
#endif
#ifdef USE_LLVM_BACKPORT_SECTION_MEMORY_MANAGER
DEFINE_SIMPLE_CONVERSION_FUNCTIONS(llvm::orc::ExecutionSession, LLVMOrcExecutionSessionRef)
DEFINE_SIMPLE_CONVERSION_FUNCTIONS(llvm::orc::ObjectLayer, LLVMOrcObjectLayerRef);
LLVMOrcObjectLayerRef
LLVMOrcCreateRTDyldObjectLinkingLayerWithSafeSectionMemoryManager(LLVMOrcExecutionSessionRef ES)
{
return wrap(new llvm::orc::RTDyldObjectLinkingLayer(
*unwrap(ES), [] { return std::make_unique<llvm::backport::SectionMemoryManager>(nullptr, true); }));
}
#endif

1
src/backend/jit/llvm/meson.build
View File

@ -14,6 +14,7 @@ llvmjit_sources += files(
'llvmjit_error.cpp',
'llvmjit_inline.cpp',
'llvmjit_wrap.cpp',
'SectionMemoryManager.cpp',
)
# Code generation

226
src/include/jit/SectionMemoryManager.h Normal file
View File

@ -0,0 +1,226 @@
/*
* This is a copy LLVM source code modified by the PostgreSQL project.
* See SectionMemoryManager.cpp for notes on provenance and license.
*/
//===- SectionMemoryManager.h - Memory manager for MCJIT/RtDyld -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains the declaration of a section-based memory manager used by
// the MCJIT execution engine and RuntimeDyld.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_EXECUTIONENGINE_BACKPORT_SECTIONMEMORYMANAGER_H
#define LLVM_EXECUTIONENGINE_BACKPORT_SECTIONMEMORYMANAGER_H
#include "llvm/ADT/SmallVector.h"
#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
#include "llvm/Support/Alignment.h"
#include "llvm/Support/Memory.h"
#include <cstdint>
#include <string>
#include <system_error>
namespace llvm {
namespace backport {
/// This is a simple memory manager which implements the methods called by
/// the RuntimeDyld class to allocate memory for section-based loading of
/// objects, usually those generated by the MCJIT execution engine.
///
/// This memory manager allocates all section memory as read-write. The
/// RuntimeDyld will copy JITed section memory into these allocated blocks
/// and perform any necessary linking and relocations.
///
/// Any client using this memory manager MUST ensure that section-specific
/// page permissions have been applied before attempting to execute functions
/// in the JITed object. Permissions can be applied either by calling
/// MCJIT::finalizeObject or by calling SectionMemoryManager::finalizeMemory
/// directly. Clients of MCJIT should call MCJIT::finalizeObject.
class SectionMemoryManager : public RTDyldMemoryManager {
public:
/// This enum describes the various reasons to allocate pages from
/// allocateMappedMemory.
enum class AllocationPurpose {
Code,
ROData,
RWData,
};
/// Implementations of this interface are used by SectionMemoryManager to
/// request pages from the operating system.
class MemoryMapper {
public:
/// This method attempts to allocate \p NumBytes bytes of virtual memory for
/// \p Purpose. \p NearBlock may point to an existing allocation, in which
/// case an attempt is made to allocate more memory near the existing block.
/// The actual allocated address is not guaranteed to be near the requested
/// address. \p Flags is used to set the initial protection flags for the
/// block of the memory. \p EC [out] returns an object describing any error
/// that occurs.
///
/// This method may allocate more than the number of bytes requested. The
/// actual number of bytes allocated is indicated in the returned
/// MemoryBlock.
///
/// The start of the allocated block must be aligned with the system
/// allocation granularity (64K on Windows, page size on Linux). If the
/// address following \p NearBlock is not so aligned, it will be rounded up
/// to the next allocation granularity boundary.
///
/// \r a non-null MemoryBlock if the function was successful, otherwise a
/// null MemoryBlock with \p EC describing the error.
virtual sys::MemoryBlock
allocateMappedMemory(AllocationPurpose Purpose, size_t NumBytes,
const sys::MemoryBlock *const NearBlock,
unsigned Flags, std::error_code &EC) = 0;
/// This method sets the protection flags for a block of memory to the state
/// specified by \p Flags. The behavior is not specified if the memory was
/// not allocated using the allocateMappedMemory method.
/// \p Block describes the memory block to be protected.
/// \p Flags specifies the new protection state to be assigned to the block.
///
/// If \p Flags is MF_WRITE, the actual behavior varies with the operating
/// system (i.e. MF_READ | MF_WRITE on Windows) and the target architecture
/// (i.e. MF_WRITE -> MF_READ | MF_WRITE on i386).
///
/// \r error_success if the function was successful, or an error_code
/// describing the failure if an error occurred.
virtual std::error_code protectMappedMemory(const sys::MemoryBlock &Block,
unsigned Flags) = 0;
/// This method releases a block of memory that was allocated with the
/// allocateMappedMemory method. It should not be used to release any memory
/// block allocated any other way.
/// \p Block describes the memory to be released.
///
/// \r error_success if the function was successful, or an error_code
/// describing the failure if an error occurred.
virtual std::error_code releaseMappedMemory(sys::MemoryBlock &M) = 0;
virtual ~MemoryMapper();
};
/// Creates a SectionMemoryManager instance with \p MM as the associated
/// memory mapper. If \p MM is nullptr then a default memory mapper is used
/// that directly calls into the operating system.
///
/// If \p ReserveAlloc is true all memory will be pre-allocated, and any
/// attempts to allocate beyond pre-allocated memory will fail.
SectionMemoryManager(MemoryMapper *MM = nullptr, bool ReserveAlloc = false);
SectionMemoryManager(const SectionMemoryManager &) = delete;
void operator=(const SectionMemoryManager &) = delete;
~SectionMemoryManager() override;
/// Enable reserveAllocationSpace when requested.
bool needsToReserveAllocationSpace() override { return ReserveAllocation; }
/// Implements allocating all memory in a single block. This is required to
/// limit memory offsets to fit the ARM ABI; large memory systems may
/// otherwise allocate separate sections too far apart.
#if LLVM_VERSION_MAJOR < 16
virtual void reserveAllocationSpace(uintptr_t CodeSize, uint32_t CodeAlign,
uintptr_t RODataSize,
uint32_t RODataAlign,
uintptr_t RWDataSize,
uint32_t RWDataAlign) override;
#else
void reserveAllocationSpace(uintptr_t CodeSize, Align CodeAlign,
uintptr_t RODataSize, Align RODataAlign,
uintptr_t RWDataSize, Align RWDataAlign) override;
#endif
/// Allocates a memory block of (at least) the given size suitable for
/// executable code.
///
/// The value of \p Alignment must be a power of two. If \p Alignment is zero
/// a default alignment of 16 will be used.
uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
unsigned SectionID,
StringRef SectionName) override;
/// Allocates a memory block of (at least) the given size suitable for
/// executable code.
///
/// The value of \p Alignment must be a power of two. If \p Alignment is zero
/// a default alignment of 16 will be used.
uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
unsigned SectionID, StringRef SectionName,
bool isReadOnly) override;
/// Update section-specific memory permissions and other attributes.
///
/// This method is called when object loading is complete and section page
/// permissions can be applied. It is up to the memory manager implementation
/// to decide whether or not to act on this method. The memory manager will
/// typically allocate all sections as read-write and then apply specific
/// permissions when this method is called. Code sections cannot be executed
/// until this function has been called. In addition, any cache coherency
/// operations needed to reliably use the memory are also performed.
///
/// \returns true if an error occurred, false otherwise.
bool finalizeMemory(std::string *ErrMsg = nullptr) override;
/// Invalidate instruction cache for code sections.
///
/// Some platforms with separate data cache and instruction cache require
/// explicit cache flush, otherwise JIT code manipulations (like resolved
/// relocations) will get to the data cache but not to the instruction cache.
///
/// This method is called from finalizeMemory.
virtual void invalidateInstructionCache();
private:
struct FreeMemBlock {
// The actual block of free memory
sys::MemoryBlock Free;
// If there is a pending allocation from the same reservation right before
// this block, store it's index in PendingMem, to be able to update the
// pending region if part of this block is allocated, rather than having to
// create a new one
unsigned PendingPrefixIndex;
};
struct MemoryGroup {
// PendingMem contains all blocks of memory (subblocks of AllocatedMem)
// which have not yet had their permissions applied, but have been given
// out to the user. FreeMem contains all block of memory, which have
// neither had their permissions applied, nor been given out to the user.
SmallVector<sys::MemoryBlock, 16> PendingMem;
SmallVector<FreeMemBlock, 16> FreeMem;
// All memory blocks that have been requested from the system
SmallVector<sys::MemoryBlock, 16> AllocatedMem;
sys::MemoryBlock Near;
};
uint8_t *allocateSection(AllocationPurpose Purpose, uintptr_t Size,
unsigned Alignment);
std::error_code applyMemoryGroupPermissions(MemoryGroup &MemGroup,
unsigned Permissions);
bool hasSpace(const MemoryGroup &MemGroup, uintptr_t Size) const;
void anchor() override;
MemoryGroup CodeMem;
MemoryGroup RWDataMem;
MemoryGroup RODataMem;
MemoryMapper *MMapper;
std::unique_ptr<MemoryMapper> OwnedMMapper;
bool ReserveAllocation;
};
} // end namespace backport
} // end namespace llvm
#endif // LLVM_EXECUTIONENGINE_BACKPORT_SECTIONMEMORYMANAGER_H

8
src/include/jit/llvmjit.h
View File

@ -17,7 +17,12 @@
*/
#ifdef USE_LLVM
#include "jit/llvmjit_backport.h"
#include <llvm-c/Types.h>
#ifdef USE_LLVM_BACKPORT_SECTION_MEMORY_MANAGER
#include <llvm-c/OrcEE.h>
#endif
/*
@ -148,6 +153,9 @@ extern char *LLVMGetHostCPUFeatures(void);
extern unsigned LLVMGetAttributeCountAtIndexPG(LLVMValueRef F, uint32 Idx);
extern LLVMTypeRef LLVMGetFunctionReturnType(LLVMValueRef r);
extern LLVMTypeRef LLVMGetFunctionType(LLVMValueRef r);
#ifdef USE_LLVM_BACKPORT_SECTION_MEMORY_MANAGER
extern LLVMOrcObjectLayerRef LLVMOrcCreateRTDyldObjectLinkingLayerWithSafeSectionMemoryManager(LLVMOrcExecutionSessionRef ES);
#endif
#if LLVM_MAJOR_VERSION < 8
extern LLVMTypeRef LLVMGlobalGetValueType(LLVMValueRef g);

25
src/include/jit/llvmjit_backport.h Normal file
View File

@ -0,0 +1,25 @@
/*
* A small header than can be included by backported LLVM code or PostgreSQL
* code, to control conditional compilation.
*/
#ifndef LLVMJIT_BACKPORT_H
#define LLVMJIT_BACKPORT_H
#include <llvm/Config/llvm-config.h>
/*
* LLVM's RuntimeDyld can produce code that crashes on larger memory ARM
* systems, because llvm::SectionMemoryManager allocates multiple pieces of
* memory that can be placed too far apart for the generated code. See
* src/backend/jit/llvm/SectionMemoryManager.cpp for the patched replacement
* class llvm::backport::SectionMemoryManager that we use as a workaround.
* This header controls whether we use it.
*
* We have adjusted it to compile against a range of LLVM versions, but not
* further back than 12 for now.
*/
#if defined(__aarch64__) && LLVM_VERSION_MAJOR > 11
#define USE_LLVM_BACKPORT_SECTION_MEMORY_MANAGER
#endif
#endif

3
src/tools/pginclude/headerscheck
View File

@ -132,6 +132,9 @@ do
# This produces a "no previous prototype" warning.
test "$f" = src/include/storage/checksum_impl.h && continue
# SectionMemoryManager.h is C++
test "$f" = src/include/jit/SectionMemoryManager.h && continue
# ppport.h is not under our control, so we can't make it standalone.
test "$f" = src/pl/plperl/ppport.h && continue

3
src/tools/pgindent/exclude_file_patterns
View File

@ -4,8 +4,9 @@
src/include/storage/s_lock\.h$
src/include/port/atomics/
#
# This contains C++ constructs that confuse pgindent.
# These contains C++ constructs that confuse pgindent.
src/include/jit/llvmjit\.h$
src/include/jit/SectionMemoryManager\.h$
#
# These are generated files with incomplete code fragments that
# confuse pgindent.