From 8f799057689934dd6099ba911a1450499a61f7b6 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Wed, 31 Dec 2025 17:35:04 +1300 Subject: [PATCH v2 1/3] jit: Skip local SectionMemoryManager for LLVM 22. LLVM 22 has the fix that we copied into our tree in commit 9044fc1d and a new function to reach it[1][2], so we only need to use our local copy for LLVM < 22. The only change that we don't have from the version that was committed is the addition of the LLVM_ABI macro to control shared library exports, but that isn't defined before LLVM 20 (our copy has to work with earlier versions), and isn't appropriate here as our copy is private and in our own library. [1] https://github.com/llvm/llvm-project/pull/71968 [2] https://github.com/llvm/llvm-project/pull/174307 Backpatch-through: 14 Discussion: https://postgr.es/m/CA%2BhUKGJTumad75o8Zao-LFseEbt%3DenbUFCM7LZVV%3Dc8yg2i7dg%40mail.gmail.com --- src/backend/jit/llvm/SectionMemoryManager.cpp | 22 ++++++------------- src/backend/jit/llvm/llvmjit.c | 5 ++++- src/include/jit/SectionMemoryManager.h | 2 +- src/include/jit/llvmjit_backport.h | 4 ++-- 4 files changed, 14 insertions(+), 19 deletions(-) diff --git a/src/backend/jit/llvm/SectionMemoryManager.cpp b/src/backend/jit/llvm/SectionMemoryManager.cpp index 2171db5f382..e113ce81a3d 100644 --- a/src/backend/jit/llvm/SectionMemoryManager.cpp +++ b/src/backend/jit/llvm/SectionMemoryManager.cpp @@ -1,25 +1,17 @@ /* - * 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. + * This file is from LLVM 22 (originally pull request #71968), with minor + * modifications to avoid name clash and work with older LLVM versions. It + * replaces llvm::SectionMemoryManager, and is injected into llvm::RuntimeDyld + * to fix a memory layout bug on large memory ARM systems on LLVM < 22. * - * 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. + * We can remove this code (.cpp, .h, .LICENSE) once LLVM 22 is our minimum + * supported version or we've switched to JITLink for at least Aarch64. * * 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. + * 4a. */ //===- SectionMemoryManager.cpp - Memory manager for MCJIT/RtDyld *- C++ -*-==// diff --git a/src/backend/jit/llvm/llvmjit.c b/src/backend/jit/llvm/llvmjit.c index 8d009dd5cf7..8fb282f6cce 100644 --- a/src/backend/jit/llvm/llvmjit.c +++ b/src/backend/jit/llvm/llvmjit.c @@ -1172,7 +1172,10 @@ 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 +#if LLVM_VERSION_MAJOR >= 22 + LLVMOrcObjectLayerRef objlayer = + LLVMOrcCreateRTDyldObjectLinkingLayerWithSectionMemoryManagerReserveAlloc(ES, true); +#elif defined(USE_LLVM_BACKPORT_SECTION_MEMORY_MANAGER) LLVMOrcObjectLayerRef objlayer = LLVMOrcCreateRTDyldObjectLinkingLayerWithSafeSectionMemoryManager(ES); #else diff --git a/src/include/jit/SectionMemoryManager.h b/src/include/jit/SectionMemoryManager.h index 924a99b0d33..4c9bd1c7f01 100644 --- a/src/include/jit/SectionMemoryManager.h +++ b/src/include/jit/SectionMemoryManager.h @@ -1,5 +1,5 @@ /* - * This is a copy LLVM source code modified by the PostgreSQL project. + * This is a copy of LLVM source code modified by the PostgreSQL project. * See SectionMemoryManager.cpp for notes on provenance and license. */ diff --git a/src/include/jit/llvmjit_backport.h b/src/include/jit/llvmjit_backport.h index cba8eafc4f3..71cfdfc832f 100644 --- a/src/include/jit/llvmjit_backport.h +++ b/src/include/jit/llvmjit_backport.h @@ -8,14 +8,14 @@ #include /* - * LLVM's RuntimeDyld can produce code that crashes on larger memory ARM + * Pre-LLVM 22 RuntimeDyld can produce code that crashes on large 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. */ -#if defined(__aarch64__) +#if defined(__aarch64__) && LLVM_VERSION_MAJOR < 22 #define USE_LLVM_BACKPORT_SECTION_MEMORY_MANAGER #endif -- 2.52.0