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Since commit 757e725b (tcg: Clean up includes) "config.h" as been
replaced by "qemu/osdep.h" which itself includes 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, 9 insertions, 9 deletions

diff --git a/tcg/mips/tcg-target.inc.c b/tcg/mips/tcg-target.inc.c
index 682e19897d..f7194b6b5f 100644
--- a/tcg/mips/tcg-target.inc.c
+++ b/tcg/mips/tcg-target.inc.c
@@ -127,7 +127,7 @@ static inline uint32_t reloc_pc16_val(tcg_insn_unit *pc, tcg_insn_unit *target)
 {
     /* Let the compiler perform the right-shift as part of the arithmetic.  */
     ptrdiff_t disp = target - (pc + 1);
-    assert(disp == (int16_t)disp);
+    tcg_debug_assert(disp == (int16_t)disp);
     return disp & 0xffff;
 }
 
@@ -138,7 +138,7 @@ static inline void reloc_pc16(tcg_insn_unit *pc, tcg_insn_unit *target)
 
 static inline uint32_t reloc_26_val(tcg_insn_unit *pc, tcg_insn_unit *target)
 {
-    assert((((uintptr_t)pc ^ (uintptr_t)target) & 0xf0000000) == 0);
+    tcg_debug_assert((((uintptr_t)pc ^ (uintptr_t)target) & 0xf0000000) == 0);
     return ((uintptr_t)target >> 2) & 0x3ffffff;
 }
 
@@ -150,8 +150,8 @@ static inline void reloc_26(tcg_insn_unit *pc, tcg_insn_unit *target)
 static void patch_reloc(tcg_insn_unit *code_ptr, int type,
                         intptr_t value, intptr_t addend)
 {
-    assert(type == R_MIPS_PC16);
-    assert(addend == 0);
+    tcg_debug_assert(type == R_MIPS_PC16);
+    tcg_debug_assert(addend == 0);
     reloc_pc16(code_ptr, (tcg_insn_unit *)value);
 }
 
@@ -432,7 +432,7 @@ static bool tcg_out_opc_jmp(TCGContext *s, MIPSInsn opc, void *target)
     if ((from ^ dest) & -(1 << 28)) {
         return false;
     }
-    assert((dest & 3) == 0);
+    tcg_debug_assert((dest & 3) == 0);
 
     inst = opc;
     inst |= (dest >> 2) & 0x3ffffff;
@@ -807,9 +807,9 @@ static void tcg_out_setcond2(TCGContext *s, TCGCond cond, TCGReg ret,
     TCGReg tmp0 = TCG_TMP0;
     TCGReg tmp1 = ret;
 
-    assert(ret != TCG_TMP0);
+    tcg_debug_assert(ret != TCG_TMP0);
     if (ret == ah || ret == bh) {
-        assert(ret != TCG_TMP1);
+        tcg_debug_assert(ret != TCG_TMP1);
         tmp1 = TCG_TMP1;
     }
 
@@ -1470,8 +1470,8 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
     case INDEX_op_and_i32:
         if (c2 && a2 != (uint16_t)a2) {
             int msb = ctz32(~a2) - 1;
-            assert(use_mips32r2_instructions);
-            assert(is_p2m1(a2));
+            tcg_debug_assert(use_mips32r2_instructions);
+            tcg_debug_assert(is_p2m1(a2));
             tcg_out_opc_bf(s, OPC_EXT, a0, a1, msb, 0);
             break;
         }