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| author | Andres Freund <andres@anarazel.de> | 2018-11-27 10:07:43 -0800 |
|---|---|---|
| committer | Andres Freund <andres@anarazel.de> | 2018-11-27 10:07:43 -0800 |
| commit | aee085bc018ffb961bf0a2c3ac72a45bb3aa33a9 (patch) | |
| tree | 9d509cb312c68e63a98997a0d27ce48bc017419b /src/backend/jit/llvm | |
| parent | 5ef8f08b541da5df1ac00a3c880578a8e3bf447c (diff) | |
| download | postgresql-aee085bc018ffb961bf0a2c3ac72a45bb3aa33a9.tar.gz postgresql-aee085bc018ffb961bf0a2c3ac72a45bb3aa33a9.zip | |
Fix jit compilation bug on wide tables.
The function generated to perform JIT compiled tuple deforming failed
when HeapTupleHeader's t_hoff was bigger than a signed int8. I'd
failed to realize that LLVM's getelementptr would treat an int8 index
argument as signed, rather than unsigned. That means that a hoff
larger than 127 would result in a negative offset being applied. Fix
that by widening the index to 32bit.
Add a testcase with a wide table. Don't drop it, as it seems useful to
verify other tools deal properly with wide tables.
Thanks to Justin Pryzby for both reporting a bug and then reducing it
to a reproducible testcase!
Reported-By: Justin Pryzby
Author: Andres Freund
Discussion: https://postgr.es/m/20181115223959.GB10913@telsasoft.com
Backpatch: 11, just as jit compilation was
Diffstat (limited to 'src/backend/jit/llvm')
| -rw-r--r-- | src/backend/jit/llvm/llvmjit_deform.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c index 795f67114e6..e406d392d4e 100644 --- a/src/backend/jit/llvm/llvmjit_deform.c +++ b/src/backend/jit/llvm/llvmjit_deform.c @@ -208,10 +208,16 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc, int natts) v_infomask2, "maxatt"); + /* + * Need to zext, as getelementptr otherwise treats hoff as a signed 8bit + * integer, which'd yield a negative offset for t_hoff > 127. + */ v_hoff = - l_load_struct_gep(b, v_tuplep, - FIELDNO_HEAPTUPLEHEADERDATA_HOFF, - "t_hoff"); + LLVMBuildZExt(b, + l_load_struct_gep(b, v_tuplep, + FIELDNO_HEAPTUPLEHEADERDATA_HOFF, + ""), + LLVMInt32Type(), "t_hoff"); v_tupdata_base = LLVMBuildGEP(b, |