diff options
author | Andres Freund | 2020-10-16 00:38:00 +0000 |
---|---|---|
committer | Andres Freund | 2020-10-16 01:17:00 +0000 |
commit | fe2a16d8b3e6fde07a8a990057e983854ad50616 (patch) | |
tree | 7a6c5d65d5f95928893b66456d490619a42118c6 | |
parent | 536de14e2bdf467aefc5e25f85056fe1adf4846d (diff) |
llvmjit: Work around bug in LLVM 3.9 causing crashes after 72559438f92.
Unfortunately in LLVM 3.9 LLVMGetAttributeCountAtIndex(func, index)
crashes when called with an index that has 0 attributes. Since there's
no way to work around this in the C API, add a small C++ wrapper doing
so.
The only reason this didn't fail before 72559438f92 is that there
always are function attributes...
Author: Andres Freund <[email protected]>
Discussion: https://postgr.es/m/[email protected]
Backpatch: 11-, like 72559438f92
-rw-r--r-- | src/backend/jit/llvm/llvmjit.c | 9 | ||||
-rw-r--r-- | src/backend/jit/llvm/llvmjit_wrap.cpp | 32 | ||||
-rw-r--r-- | src/include/jit/llvmjit.h | 2 |
3 files changed, 42 insertions, 1 deletions
diff --git a/src/backend/jit/llvm/llvmjit.c b/src/backend/jit/llvm/llvmjit.c index 7965b61165..4c026d37d0 100644 --- a/src/backend/jit/llvm/llvmjit.c +++ b/src/backend/jit/llvm/llvmjit.c @@ -333,7 +333,14 @@ llvm_copy_attributes_at_index(LLVMValueRef v_from, LLVMValueRef v_to, uint32 ind int num_attributes; LLVMAttributeRef *attrs; - num_attributes = LLVMGetAttributeCountAtIndex(v_from, index); + num_attributes = LLVMGetAttributeCountAtIndexPG(v_from, index); + + /* + * Not just for efficiency: LLVM <= 3.9 crashes when + * LLVMGetAttributesAtIndex() is called for an index with 0 attributes. + */ + if (num_attributes == 0) + return; attrs = palloc(sizeof(LLVMAttributeRef) * num_attributes); LLVMGetAttributesAtIndex(v_from, index, attrs); diff --git a/src/backend/jit/llvm/llvmjit_wrap.cpp b/src/backend/jit/llvm/llvmjit_wrap.cpp index e8a7380325..37c006a1ff 100644 --- a/src/backend/jit/llvm/llvmjit_wrap.cpp +++ b/src/backend/jit/llvm/llvmjit_wrap.cpp @@ -16,6 +16,13 @@ extern "C" #include "postgres.h" } +#include <llvm-c/Core.h> + +/* Avoid macro clash with LLVM's C++ headers */ +#undef Min + +#include <llvm/IR/Attributes.h> +#include <llvm/IR/Function.h> #include <llvm/MC/SubtargetFeature.h> #include <llvm/Support/Host.h> @@ -44,3 +51,28 @@ char *LLVMGetHostCPUFeatures(void) { return strdup(Features.getString().c_str()); } #endif + +/* + * Like LLVM's LLVMGetAttributeCountAtIndex(), works around a bug in LLVM 3.9. + * + * In LLVM <= 3.9, LLVMGetAttributeCountAtIndex() segfaults if there are no + * attributes at an index (fixed in LLVM commit ce9bb1097dc2). + */ +unsigned +LLVMGetAttributeCountAtIndexPG(LLVMValueRef F, uint32 Idx) +{ + /* + * This is more expensive, so only do when using a problematic LLVM + * version. + */ +#if LLVM_VERSION_MAJOR < 4 + if (!llvm::unwrap<llvm::Function>(F)->getAttributes().hasAttributes(Idx)) + return 0; +#endif + + /* + * There is no nice public API to determine the count nicely, so just + * always fall back to LLVM's C API. + */ + return LLVMGetAttributeCountAtIndex(F, Idx); +} diff --git a/src/include/jit/llvmjit.h b/src/include/jit/llvmjit.h index 706906c1cc..325409acd5 100644 --- a/src/include/jit/llvmjit.h +++ b/src/include/jit/llvmjit.h @@ -129,6 +129,8 @@ extern char *LLVMGetHostCPUName(void); extern char *LLVMGetHostCPUFeatures(void); #endif +extern unsigned LLVMGetAttributeCountAtIndexPG(LLVMValueRef F, uint32 Idx); + #ifdef __cplusplus } /* extern "C" */ #endif |