jit: Correct parameter type for generated expression evaluation functions.

anarazel · anarazel · commit 1e16ad101459 · 2020-12-07T18:40:27.000-08:00
clang only uses the 'i1' type for scalar booleans, not for pointers to booleans (as the pointer might be pointing into a larger memory allocation). Therefore a pointer-to-bool needs to the "storage" boolean. There's no known case of wrong code generation due to this, but it seems quite possible that it could cause problems (see e.g. 7255943). Author: Andres Freund Discussion: https://postgr.es/m/20201207212142.wz5tnbk2jsaqzogb@alap3.anarazel.de Backpatch: 11-, where jit support was added
diff --git a/src/backend/jit/llvm/llvmjit_expr.c b/src/backend/jit/llvm/llvmjit_expr.c
@@ -152,7 +152,7 @@ llvm_compile_expr(ExprState *state)
 
 		param_types[0] = l_ptr(StructExprState);	/* state */
 		param_types[1] = l_ptr(StructExprContext);	/* econtext */
-		param_types[2] = l_ptr(TypeParamBool);	/* isnull */
+		param_types[2] = l_ptr(TypeStorageBool);	/* isnull */
 
 		eval_sig = LLVMFunctionType(TypeSizeT,
 									param_types, lengthof(param_types),
@@ -259,8 +259,6 @@ llvm_compile_expr(ExprState *state)
 
 					v_tmpvalue = LLVMBuildLoad(b, v_tmpvaluep, "");
 					v_tmpisnull = LLVMBuildLoad(b, v_tmpisnullp, "");
-					v_tmpisnull =
-						LLVMBuildTrunc(b, v_tmpisnull, TypeParamBool, "");
 
 					LLVMBuildStore(b, v_tmpisnull, v_isnullp);
 
