tcg: use tcg_debug_assert instead of assert (fix performance regression)

The TCG code is quite performance sensitive, but at the same time can
also be quite tricky. That is why asserts that can be enabled with the
--enable-debug-tcg configure option.

This used to work the following way:

| #include "config.h"
|
| ...
|
| #if !defined(CONFIG_DEBUG_TCG) && !defined(NDEBUG)
| /* define it to suppress various consistency checks (faster) */
| #define NDEBUG
| #endif
|
| ...
|
| #include <assert.h>

Since commit 757e725b (tcg: Clean up includes) "config.h" as been
replaced by "qemu/osdep.h" which itself includes <assert.h>. As a
consequence the assertions are always enabled, even when using
--disable-debug-tcg, causing a performance regression, especially on
targets with many registers. For instance on qemu-system-ppc the
speed difference is about 15%.

tcg_debug_assert is controlled directly by CONFIG_DEBUG_TCG and already
uses in some places. This patch replaces all the calls to assert into
calss to tcg_debug_assert.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Message-id: 1461228530-14852-1-git-send-email-aurelien@aurel32.net
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/tcg/arm/tcg-target.inc.c b/tcg/arm/tcg-target.inc.c
index 3edf6a6..9995b74 100644
--- a/tcg/arm/tcg-target.inc.c
+++ b/tcg/arm/tcg-target.inc.c
@@ -124,8 +124,8 @@ static inline void reloc_pc24(tcg_insn_unit *code_ptr, tcg_insn_unit *target)
 static void patch_reloc(tcg_insn_unit *code_ptr, int type,
                         intptr_t value, intptr_t addend)
 {
-    assert(type == R_ARM_PC24);
-    assert(addend == 0);
+    tcg_debug_assert(type == R_ARM_PC24);
+    tcg_debug_assert(addend == 0);
     reloc_pc24(code_ptr, (tcg_insn_unit *)value);
 }
 
@@ -492,7 +492,7 @@ static inline void tcg_out_dat_rI(TCGContext *s, int cond, int opc, TCGArg dst,
      */
     if (rhs_is_const) {
         int rot = encode_imm(rhs);
-        assert(rot >= 0);
+        tcg_debug_assert(rot >= 0);
         tcg_out_dat_imm(s, cond, opc, dst, lhs, rotl(rhs, rot) | (rot << 7));
     } else {
         tcg_out_dat_reg(s, cond, opc, dst, lhs, rhs, SHIFT_IMM_LSL(0));
@@ -511,7 +511,7 @@ static void tcg_out_dat_rIK(TCGContext *s, int cond, int opc, int opinv,
         if (rot < 0) {
             rhs = ~rhs;
             rot = encode_imm(rhs);
-            assert(rot >= 0);
+            tcg_debug_assert(rot >= 0);
             opc = opinv;
         }
         tcg_out_dat_imm(s, cond, opc, dst, lhs, rotl(rhs, rot) | (rot << 7));
@@ -532,7 +532,7 @@ static void tcg_out_dat_rIN(TCGContext *s, int cond, int opc, int opneg,
         if (rot < 0) {
             rhs = -rhs;
             rot = encode_imm(rhs);
-            assert(rot >= 0);
+            tcg_debug_assert(rot >= 0);
             opc = opneg;
         }
         tcg_out_dat_imm(s, cond, opc, dst, lhs, rotl(rhs, rot) | (rot << 7));
@@ -1100,7 +1100,7 @@ static TCGReg NAME(TCGContext *s, TCGReg argreg, ARGTYPE arg)              \
     } else {                                                               \
         int ofs = (argreg - 4) * 4;                                        \
         EXT_ARG;                                                           \
-        assert(ofs + 4 <= TCG_STATIC_CALL_ARGS_SIZE);                      \
+        tcg_debug_assert(ofs + 4 <= TCG_STATIC_CALL_ARGS_SIZE);            \
         tcg_out_st32_12(s, COND_AL, arg, TCG_REG_CALL_STACK, ofs);         \
     }                                                                      \
     return argreg + 1;                                                     \