Fix StaticTracepoint argument size type identification

Summary:
We need to determine the size of the Tracepoint arguments in the Macro. The only exception that we can not simply take `sizeof` is arrays, where `sizeof` will return size of the array where we really want is size of a pointer. Before we specifically check this with `FOLLY_SDT_ISARRAY` which checks if `__builtin_classify_type` of the argument is 14. However in recent update of LLVM, some arrays will be reported with type 5 (pointer type). Originally we didn't add that because we thought if the type of the argument is already a pointer then just take a `sizeof` on it would still be correct. This Diff fixes the issue.

LLVM change in question is https://reviews.llvm.org/rL333126

Reviewed By: taewookoh

Differential Revision: D10453657

fbshipit-source-id: 154fdfc78fe6438cd66cf256203c8d174773c1a8

folly/tracing/StaticTracepoint-ELFx86.h

@@ -50,8 +50,11 @@
 #define FOLLY_SDT_ASM_STRING(x)       FOLLY_SDT_ASM_1(.asciz FOLLY_SDT_S(x))
 
 // Helper to determine the size of an argument.
-#define FOLLY_SDT_ISARRAY(x)  (__builtin_classify_type(x) == 14)
-#define FOLLY_SDT_ARGSIZE(x)  (FOLLY_SDT_ISARRAY(x) ? sizeof(void*) : sizeof(x))
+#define FOLLY_SDT_IS_ARRAY_POINTER(x)  ((__builtin_classify_type(x) == 14) ||  \
+                                        (__builtin_classify_type(x) == 5))
+#define FOLLY_SDT_ARGSIZE(x)  (FOLLY_SDT_IS_ARRAY_POINTER(x)                   \
+                               ? sizeof(void*)                                 \
+                               : sizeof(x))
 
 // Format of each probe arguments as operand.
 // Size of the arugment tagged with FOLLY_SDT_Sn, with "n" constraint.