From 72559438f92f9a7d9205192bef601be953c7bd2a Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Thu, 15 Oct 2020 13:39:41 -0700 Subject: [PATCH] llvmjit: Also copy parameter / return value attributes from template functions. Previously we only copied the function attributes. That caused problems at least on s390x: Because we didn't copy the 'zeroext' attribute for ExecAggTransReparent()'s *IsNull parameters, expressions invoking it didn't ensure that the upper bytes of the registers were zeroed. In the - relatively rare - cases where not, ExecAggTransReparent() wrongly ended up in the newValueIsNull branch due to the register not being zero. Subsequently causing a crash. It's quite possible that this would cause problems on other platforms, and in other places than just ExecAggTransReparent() on s390x. Thanks to Christoph (and the Debian project) for providing me with access to a s390x machine, allowing me to debug this. Reported-By: Christoph Berg Author: Andres Freund Discussion: https://postgr.es/m/20201015083246.kie5726xerdt3ael@alap3.anarazel.de Backpatch: 11-, where JIT was added --- src/backend/jit/llvm/llvmjit.c | 46 ++++++++++++++++++++++++---------- 1 file changed, 33 insertions(+), 13 deletions(-) diff --git a/src/backend/jit/llvm/llvmjit.c b/src/backend/jit/llvm/llvmjit.c index 43bed78a52..7965b61165 100644 --- a/src/backend/jit/llvm/llvmjit.c +++ b/src/backend/jit/llvm/llvmjit.c @@ -324,26 +324,46 @@ llvm_pg_func(LLVMModuleRef mod, const char *funcname) } /* - * Copy attributes from one function to another. + * Copy attributes from one function to another, for a specific index (an + * index can reference return value, function and parameter attributes). + */ +static void +llvm_copy_attributes_at_index(LLVMValueRef v_from, LLVMValueRef v_to, uint32 index) +{ + int num_attributes; + LLVMAttributeRef *attrs; + + num_attributes = LLVMGetAttributeCountAtIndex(v_from, index); + + attrs = palloc(sizeof(LLVMAttributeRef) * num_attributes); + LLVMGetAttributesAtIndex(v_from, index, attrs); + + for (int attno = 0; attno < num_attributes; attno++) + LLVMAddAttributeAtIndex(v_to, index, attrs[attno]); + + pfree(attrs); +} + +/* + * Copy all attributes from one function to another. I.e. function, return and + * parameters will be copied. */ void llvm_copy_attributes(LLVMValueRef v_from, LLVMValueRef v_to) { - int num_attributes; - int attno; - LLVMAttributeRef *attrs; + uint32 param_count; - num_attributes = - LLVMGetAttributeCountAtIndex(v_from, LLVMAttributeFunctionIndex); + /* copy function attributes */ + llvm_copy_attributes_at_index(v_from, v_to, LLVMAttributeFunctionIndex); - attrs = palloc(sizeof(LLVMAttributeRef) * num_attributes); - LLVMGetAttributesAtIndex(v_from, LLVMAttributeFunctionIndex, attrs); + /* and the return value attributes */ + llvm_copy_attributes_at_index(v_from, v_to, LLVMAttributeReturnIndex); - for (attno = 0; attno < num_attributes; attno++) - { - LLVMAddAttributeAtIndex(v_to, LLVMAttributeFunctionIndex, - attrs[attno]); - } + /* and each function parameter's attribute */ + param_count = LLVMCountParams(v_from); + + for (int paramidx = 1; paramidx <= param_count; paramidx++) + llvm_copy_attributes_at_index(v_from, v_to, paramidx); } /*