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Add expression compilation support to LLVM JIT provider.

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In addition to the interpretation of expressions (which back
evaluation of WHERE clauses, target list projection, aggregates
transition values etc) support compiling expressions to native code,
using the infrastructure added in earlier commits.

To avoid duplicating a lot of code, only support emitting code for
cases that are likely to be performance critical. For expression steps
that aren't deemed that, use the existing interpreter.

The generated code isn't great - some architectural changes are
required to address that. But this already yields a significant
speedup for some analytics queries, particularly with WHERE clauses
filtering a lot, or computing multiple aggregates.

Author: Andres Freund
Tested-By: Thomas Munro
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de

Disable JITing for VALUES() nodes.

VALUES() nodes are only ever executed once. This is primarily helpful
for debugging, when forcing JITing even for cheap queries.

Author: Andres Freund
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
This commit is contained in:
Andres Freund
2018-03-20 02:20:46 -07:00
parent 7ced1d1247
commit 2a0faed9d7
13 changed files with 2890 additions and 3 deletions
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64
src/backend/jit/llvm/llvmjit.c
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@ -14,6 +14,7 @@
#include "postgres.h"
#include "jit/llvmjit.h"
#include "jit/llvmjit_emit.h"
#include "miscadmin.h"
@ -114,6 +115,7 @@ _PG_jit_provider_init(JitProviderCallbacks *cb)
{
cb->reset_after_error = llvm_reset_after_error;
cb->release_context = llvm_release_context;
cb->compile_expr = llvm_compile_expr;
}
/*
@ -339,6 +341,68 @@ llvm_copy_attributes(LLVMValueRef v_from, LLVMValueRef v_to)
}
}
/*
* Return a callable LLVMValueRef for fcinfo.
*/
LLVMValueRef
llvm_function_reference(LLVMJitContext *context,
LLVMBuilderRef builder,
LLVMModuleRef mod,
FunctionCallInfo fcinfo)
{
char *modname;
char *basename;
char *funcname;
LLVMValueRef v_fn;
fmgr_symbol(fcinfo->flinfo->fn_oid, &modname, &basename);
if (modname != NULL && basename != NULL)
{
/* external function in loadable library */
funcname = psprintf("pgextern.%s.%s", modname, basename);
}
else if (basename != NULL)
{
/* internal function */
funcname = psprintf("%s", basename);
}
else
{
/*
* Function we don't know to handle, return pointer. We do so by
* creating a global constant containing a pointer to the function.
* Makes IR more readable.
*/
LLVMValueRef v_fn_addr;
funcname = psprintf("pgoidextern.%u",
fcinfo->flinfo->fn_oid);
v_fn = LLVMGetNamedGlobal(mod, funcname);
if (v_fn != 0)
return LLVMBuildLoad(builder, v_fn, "");
v_fn_addr = l_ptr_const(fcinfo->flinfo->fn_addr, TypePGFunction);
v_fn = LLVMAddGlobal(mod, TypePGFunction, funcname);
LLVMSetInitializer(v_fn, v_fn_addr);
LLVMSetGlobalConstant(v_fn, true);
return LLVMBuildLoad(builder, v_fn, "");
return v_fn;
}
/* check if function already has been added */
v_fn = LLVMGetNamedFunction(mod, funcname);
if (v_fn != 0)
return v_fn;
v_fn = LLVMAddFunction(mod, funcname, LLVMGetElementType(TypePGFunction));
return v_fn;
}
/*
* Optimize code in module using the flags set in context.
*/