llvmjit: Use explicit LLVMContextRef for inlining

When performing inlining LLVM unfortunately "leaks" types (the
types survive and are usable, but a new round of inlining will
recreate new structurally equivalent types). This accumulation
will over time amount to a memory leak which for some queries
can be large enough to trigger the OOM process killer.

To avoid accumulation of types, all IR related data is stored
in an LLVMContextRef which is dropped and recreated in order
to release all types.  Dropping and recreating incurs overhead,
so it will be done only after 100 queries. This is a heuristic
which might be revisited, but until we can get the size of the
context from LLVM we are flying a bit blind.

This issue has been reported several times, there may be more
references to it in the archives on top of the threads linked
below.

This is a backpatch of 9dce22033d5 to all supported branches.

Reported-By: Justin Pryzby <pryzby@telsasoft.com>
Reported-By: Kurt Roeckx <kurt@roeckx.be>
Reported-By: Jaime Casanova <jcasanov@systemguards.com.ec>
Reported-By: Lauri Laanmets <pcspets@gmail.com>
Author: Andres Freund and Daniel Gustafsson
Discussion: https://postgr.es/m/7acc8678-df5f-4923-9cf6-e843131ae89d@www.fastmail.com
Discussion: https://postgr.es/m/20201218235607.GC30237@telsasoft.com
Discussion: https://postgr.es/m/CAPH-tTxLf44s3CvUUtQpkDr1D8Hxqc2NGDzGXS1ODsfiJ6WSqA@mail.gmail.com
Backpatch-through: v12

1 files changed, 40 insertions, 37 deletions

diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 60a677ba439..1014ea7a224 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -37,6 +37,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 	char	   *funcname;
 
 	LLVMModuleRef mod;
+	LLVMContextRef lc;
 	LLVMBuilderRef b;
 
 	LLVMTypeRef deform_sig;
@@ -99,6 +100,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		return NULL;
 
 	mod = llvm_mutable_module(context);
+	lc = LLVMGetModuleContext(mod);
 
 	funcname = llvm_expand_funcname(context, "deform");
 
@@ -133,8 +135,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 
 		param_types[0] = l_ptr(StructTupleTableSlot);
 
-		deform_sig = LLVMFunctionType(LLVMVoidType(), param_types,
-									  lengthof(param_types), 0);
+		deform_sig = LLVMFunctionType(LLVMVoidTypeInContext(lc),
+									  param_types, lengthof(param_types), 0);
 	}
 	v_deform_fn = LLVMAddFunction(mod, funcname, deform_sig);
 	LLVMSetLinkage(v_deform_fn, LLVMInternalLinkage);
@@ -142,17 +144,17 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 	llvm_copy_attributes(AttributeTemplate, v_deform_fn);
 
 	b_entry =
-		LLVMAppendBasicBlock(v_deform_fn, "entry");
+		LLVMAppendBasicBlockInContext(lc, v_deform_fn, "entry");
 	b_adjust_unavail_cols =
-		LLVMAppendBasicBlock(v_deform_fn, "adjust_unavail_cols");
+		LLVMAppendBasicBlockInContext(lc, v_deform_fn, "adjust_unavail_cols");
 	b_find_start =
-		LLVMAppendBasicBlock(v_deform_fn, "find_startblock");
+		LLVMAppendBasicBlockInContext(lc, v_deform_fn, "find_startblock");
 	b_out =
-		LLVMAppendBasicBlock(v_deform_fn, "outblock");
+		LLVMAppendBasicBlockInContext(lc, v_deform_fn, "outblock");
 	b_dead =
-		LLVMAppendBasicBlock(v_deform_fn, "deadblock");
+		LLVMAppendBasicBlockInContext(lc, v_deform_fn, "deadblock");
 
-	b = LLVMCreateBuilder();
+	b = LLVMCreateBuilderInContext(lc);
 
 	attcheckattnoblocks = palloc(sizeof(LLVMBasicBlockRef) * natts);
 	attstartblocks = palloc(sizeof(LLVMBasicBlockRef) * natts);
@@ -233,7 +235,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 									  v_tuplep,
 									  FIELDNO_HEAPTUPLEHEADERDATA_BITS,
 									  ""),
-						 l_ptr(LLVMInt8Type()),
+						 l_ptr(LLVMInt8TypeInContext(lc)),
 						 "t_bits");
 	v_infomask1 =
 		l_load_struct_gep(b,
@@ -251,14 +253,14 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 	v_hasnulls =
 		LLVMBuildICmp(b, LLVMIntNE,
 					  LLVMBuildAnd(b,
-								   l_int16_const(HEAP_HASNULL),
+								   l_int16_const(lc, HEAP_HASNULL),
 								   v_infomask1, ""),
-					  l_int16_const(0),
+					  l_int16_const(lc, 0),
 					  "hasnulls");
 
 	/* t_infomask2 & HEAP_NATTS_MASK */
 	v_maxatt = LLVMBuildAnd(b,
-							l_int16_const(HEAP_NATTS_MASK),
+							l_int16_const(lc, HEAP_NATTS_MASK),
 							v_infomask2,
 							"maxatt");
 
@@ -273,13 +275,13 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 										v_tuplep,
 										FIELDNO_HEAPTUPLEHEADERDATA_HOFF,
 										""),
-					  LLVMInt32Type(), "t_hoff");
+					  LLVMInt32TypeInContext(lc), "t_hoff");
 
 	v_tupdata_base = l_gep(b,
-						   LLVMInt8Type(),
+						   LLVMInt8TypeInContext(lc),
 						   LLVMBuildBitCast(b,
 											v_tuplep,
-											l_ptr(LLVMInt8Type()),
+											l_ptr(LLVMInt8TypeInContext(lc)),
 											""),
 						   &v_hoff, 1,
 						   "v_tupdata_base");
@@ -291,7 +293,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 	{
 		LLVMValueRef v_off_start;
 
-		v_off_start = l_load(b, LLVMInt32Type(), v_slotoffp, "v_slot_off");
+		v_off_start = l_load(b, LLVMInt32TypeInContext(lc), v_slotoffp, "v_slot_off");
 		v_off_start = LLVMBuildZExt(b, v_off_start, TypeSizeT, "");
 		LLVMBuildStore(b, v_off_start, v_offp);
 	}
@@ -337,7 +339,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		LLVMBuildCondBr(b,
 						LLVMBuildICmp(b, LLVMIntULT,
 									  v_maxatt,
-									  l_int16_const(natts),
+									  l_int16_const(lc, natts),
 									  ""),
 						b_adjust_unavail_cols,
 						b_find_start);
@@ -346,8 +348,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		LLVMPositionBuilderAtEnd(b, b_adjust_unavail_cols);
 
 		v_params[0] = v_slot;
-		v_params[1] = LLVMBuildZExt(b, v_maxatt, LLVMInt32Type(), "");
-		v_params[2] = l_int32_const(natts);
+		v_params[1] = LLVMBuildZExt(b, v_maxatt, LLVMInt32TypeInContext(lc), "");
+		v_params[2] = l_int32_const(lc, natts);
 		f = llvm_pg_func(mod, "slot_getmissingattrs");
 		l_call(b,
 			   LLVMGetFunctionType(f), f,
@@ -357,7 +359,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 
 	LLVMPositionBuilderAtEnd(b, b_find_start);
 
-	v_nvalid = l_load(b, LLVMInt16Type(), v_nvalidp, "");
+	v_nvalid = l_load(b, LLVMInt16TypeInContext(lc), v_nvalidp, "");
 
 	/*
 	 * Build switch to go from nvalid to the right startblock.  Callers
@@ -372,7 +374,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 
 		for (attnum = 0; attnum < natts; attnum++)
 		{
-			LLVMValueRef v_attno = l_int16_const(attnum);
+			LLVMValueRef v_attno = l_int16_const(lc, attnum);
 
 			LLVMAddCase(v_switch, v_attno, attcheckattnoblocks[attnum]);
 		}
@@ -396,7 +398,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		Form_pg_attribute att = TupleDescAttr(desc, attnum);
 		LLVMValueRef v_incby;
 		int			alignto;
-		LLVMValueRef l_attno = l_int16_const(attnum);
+		LLVMValueRef l_attno = l_int16_const(lc, attnum);
 		LLVMValueRef v_attdatap;
 		LLVMValueRef v_resultp;
 
@@ -457,14 +459,14 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			else
 				b_next = attcheckattnoblocks[attnum + 1];
 
-			v_nullbyteno = l_int32_const(attnum >> 3);
-			v_nullbytemask = l_int8_const(1 << ((attnum) & 0x07));
-			v_nullbyte = l_load_gep1(b, LLVMInt8Type(), v_bits, v_nullbyteno, "attnullbyte");
+			v_nullbyteno = l_int32_const(lc, attnum >> 3);
+			v_nullbytemask = l_int8_const(lc, 1 << ((attnum) & 0x07));
+			v_nullbyte = l_load_gep1(b, LLVMInt8TypeInContext(lc), v_bits, v_nullbyteno, "attnullbyte");
 
 			v_nullbit = LLVMBuildICmp(b,
 									  LLVMIntEQ,
 									  LLVMBuildAnd(b, v_nullbyte, v_nullbytemask, ""),
-									  l_int8_const(0),
+									  l_int8_const(lc, 0),
 									  "attisnull");
 
 			v_attisnull = LLVMBuildAnd(b, v_hasnulls, v_nullbit, "");
@@ -475,8 +477,8 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 
 			/* store null-byte */
 			LLVMBuildStore(b,
-						   l_int8_const(1),
-						   l_gep(b, LLVMInt8Type(), v_tts_nulls, &l_attno, 1, ""));
+						   l_int8_const(lc, 1),
+						   l_gep(b, LLVMInt8TypeInContext(lc), v_tts_nulls, &l_attno, 1, ""));
 			/* store zero datum */
 			LLVMBuildStore(b,
 						   l_sizet_const(0),
@@ -542,10 +544,11 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 				v_off = l_load(b, TypeSizeT, v_offp, "");
 
 				v_possible_padbyte =
-					l_load_gep1(b, LLVMInt8Type(), v_tupdata_base, v_off, "padbyte");
+					l_load_gep1(b, LLVMInt8TypeInContext(lc), v_tupdata_base,
+								v_off, "padbyte");
 				v_ispad =
 					LLVMBuildICmp(b, LLVMIntEQ,
-								  v_possible_padbyte, l_int8_const(0),
+								  v_possible_padbyte, l_int8_const(lc, 0),
 								  "ispadbyte");
 				LLVMBuildCondBr(b, v_ispad,
 								attalignblocks[attnum],
@@ -653,14 +656,14 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			LLVMValueRef v_off = l_load(b, TypeSizeT, v_offp, "");
 
 			v_attdatap =
-				l_gep(b, LLVMInt8Type(), v_tupdata_base, &v_off, 1, "");
+				l_gep(b, LLVMInt8TypeInContext(lc), v_tupdata_base, &v_off, 1, "");
 		}
 
 		/* compute address to store value at */
 		v_resultp = l_gep(b, TypeSizeT, v_tts_values, &l_attno, 1, "");
 
 		/* store null-byte (false) */
-		LLVMBuildStore(b, l_int8_const(0),
+		LLVMBuildStore(b, l_int8_const(lc, 0),
 					   l_gep(b, TypeStorageBool, v_tts_nulls, &l_attno, 1, ""));
 
 		/*
@@ -670,7 +673,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		if (att->attbyval)
 		{
 			LLVMValueRef v_tmp_loaddata;
-			LLVMTypeRef vartype = LLVMIntType(att->attlen * 8);
+			LLVMTypeRef vartype = LLVMIntTypeInContext(lc, att->attlen * 8);
 			LLVMTypeRef vartypep = LLVMPointerType(vartype, 0);
 
 			v_tmp_loaddata =
@@ -762,11 +765,11 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 		LLVMValueRef v_off = l_load(b, TypeSizeT, v_offp, "");
 		LLVMValueRef v_flags;
 
-		LLVMBuildStore(b, l_int16_const(natts), v_nvalidp);
-		v_off = LLVMBuildTrunc(b, v_off, LLVMInt32Type(), "");
+		LLVMBuildStore(b, l_int16_const(lc, natts), v_nvalidp);
+		v_off = LLVMBuildTrunc(b, v_off, LLVMInt32TypeInContext(lc), "");
 		LLVMBuildStore(b, v_off, v_slotoffp);
-		v_flags = l_load(b, LLVMInt16Type(), v_flagsp, "tts_flags");
-		v_flags = LLVMBuildOr(b, v_flags, l_int16_const(TTS_FLAG_SLOW), "");
+		v_flags = l_load(b, LLVMInt16TypeInContext(lc), v_flagsp, "tts_flags");
+		v_flags = LLVMBuildOr(b, v_flags, l_int16_const(lc, TTS_FLAG_SLOW), "");
 		LLVMBuildStore(b, v_flags, v_flagsp);
 		LLVMBuildRetVoid(b);
 	}