i#2360: consistently label nzcvqg as arithmetic on ARM (#2362)

DR considers the Q and GE flags to be arithmetic for saving, restoring, and
in the EFLAGS_ARITH constant, yet not in the EFLAGS_{READ,WRITE}_ARITH
defines.  We correct that here by including them in all arithmetic
defines.

Re-enables the drreg test that was broken because of this.

Relaxes a drreg assert on re-spilling to the aflags slot with different
regs, which is exposed by this fix.  This relaxation mirrors what we
already do on restoring aflags.

Fixes #2360

core/arch/instr.h

@@ -2863,8 +2863,9 @@ enum {
 # define EFLAGS_READ_GE     0x00000020 /**< Reads GE (>= for parallel arithmetic). */
 # define EFLAGS_READ_NZCV   (EFLAGS_READ_N | EFLAGS_READ_Z |\
                              EFLAGS_READ_C | EFLAGS_READ_V)
-# define EFLAGS_READ_ARITH  EFLAGS_READ_NZCV /**< Reads all arithmetic flags. */
-# define EFLAGS_READ_ALL    (EFLAGS_READ_NZCV | EFLAGS_READ_GE) /**< Reads all flags. */
+/** Platform-independent macro for reads all arithmetic flags. */
+# define EFLAGS_READ_ARITH  (EFLAGS_READ_NZCV | EFLAGS_READ_Q | EFLAGS_READ_GE)
+# define EFLAGS_READ_ALL    (EFLAGS_READ_ARITH) /**< Reads all flags. */
 # define EFLAGS_READ_NON_PRED EFLAGS_READ_GE /**< Flags not read by predicates. */
 # define EFLAGS_WRITE_N     0x00000040 /**< Reads N (negative). */
 # define EFLAGS_WRITE_Z     0x00000080 /**< Reads Z (zero). */
@@ -2874,13 +2875,9 @@ enum {
 # define EFLAGS_WRITE_GE    0x00000800 /**< Reads GE (>= for parallel arithmetic). */
 # define EFLAGS_WRITE_NZCV  (EFLAGS_WRITE_N | EFLAGS_WRITE_Z |\
                              EFLAGS_WRITE_C | EFLAGS_WRITE_V)
-# define EFLAGS_WRITE_ARITH EFLAGS_WRITE_NZCV /**< Reads all arithmetic flags. */
-# define EFLAGS_WRITE_ALL   (EFLAGS_WRITE_NZCV | EFLAGS_WRITE_GE) /**< Reads all flags. */
-
-/** Platform-independent macro for reads all arithmetic flags. */
-# define EFLAGS_READ_ARITH   EFLAGS_READ_NZCV
-/** Platform-independent macor for writes all arithmetic flags. */
-# define EFLAGS_WRITE_ARITH  EFLAGS_WRITE_NZCV
+/** Platform-independent macro for writes all arithmetic flags. */
+# define EFLAGS_WRITE_ARITH (EFLAGS_WRITE_NZCV | EFLAGS_WRITE_Q | EFLAGS_WRITE_GE)
+# define EFLAGS_WRITE_ALL   (EFLAGS_WRITE_ARITH) /**< Writes all flags. */
 
 /** Converts an EFLAGS_WRITE_* value to the corresponding EFLAGS_READ_* value. */
 # define EFLAGS_WRITE_TO_READ(x) ((x) >> 6)

ext/drreg/drreg.c

@@ -185,7 +185,10 @@ spill_reg(void *drcontext, per_thread_t *pt, reg_id_t reg, uint slot,
         "%s @%d."PFX" %s %d\n", __FUNCTION__, pt->live_idx, instr_get_app_pc(where),
         get_register_name(reg), slot);
     ASSERT(pt->slot_use[slot] == DR_REG_NULL ||
-           pt->slot_use[slot] == reg, "internal tracking error");
+           pt->slot_use[slot] == reg ||
+           /* aflags can be saved and restored using different regs */
+           slot == AFLAGS_SLOT,
+           "internal tracking error");
     pt->slot_use[slot] = reg;
     if (slot < ops.num_spill_slots) {
         dr_insert_write_raw_tls(drcontext, ilist, where, tls_seg,

suite/tests/api/ir_arm.c

@@ -1,5 +1,5 @@
 /* **********************************************************
- * Copyright (c) 2015-2016 Google, Inc.  All rights reserved.
+ * Copyright (c) 2015-2017 Google, Inc.  All rights reserved.
  * **********************************************************/
 
 /*
@@ -88,8 +88,8 @@ test_pred(void *dc)
          (dc, opnd_create_reg(DR_REG_R0), opnd_create_reg(DR_REG_R1),
           opnd_create_reg(DR_REG_R1)),
          DR_PRED_EQ);
-    ASSERT(instr_get_eflags(inst, DR_QUERY_INCLUDE_COND_SRCS) == EFLAGS_READ_ALL);
-    ASSERT(instr_get_eflags(inst, 0) == EFLAGS_READ_ARITH);
+    ASSERT(instr_get_eflags(inst, DR_QUERY_INCLUDE_COND_SRCS) == EFLAGS_READ_ARITH);
+    ASSERT(instr_get_eflags(inst, 0) == (EFLAGS_READ_ARITH & (~EFLAGS_READ_GE)));
     instr_free(dc, inst);
     inst = INSTR_CREATE_sel
         (dc, opnd_create_reg(DR_REG_R0), opnd_create_reg(DR_REG_R1),

suite/tests/client-interface/drreg-test.dll.c

@@ -156,11 +156,10 @@ event_app_instruction(void *drcontext, void *tag, instrlist_t *bb, instr_t *inst
         CHECK(res == DRREG_SUCCESS, "unreserve should work");
 
         /* test aflags */
-        /* FIXME i#2360: ARM's arith flags are inconsistent */
         /* FIXME i#2263: AArch64 fails to mark what flags are used in the IR, breaking
          * use of aflags in instrumentation.
          */
-#ifndef AARCHXX
+#ifndef AARCH64
         res = drreg_reserve_aflags(drcontext, bb, inst);
         CHECK(res == DRREG_SUCCESS, "reserve of aflags should work");
         res = drreg_restore_app_aflags(drcontext, bb, inst);