tcg: move tcg_use_softmmu to tcg/tcg-internal.h

In next commit, we'll apply same helper pattern for base helpers
remaining.

Our new helper pattern always include helper-*-common.h, which ends up
including include/tcg/tcg.h, which contains one occurrence of
CONFIG_USER_ONLY.
Thus, common files not being duplicated between system and target
relying on helpers will fail to compile. Existing occurrences are:
- target/arm/tcg/arith_helper.c
- target/arm/tcg/crypto_helper.c

This occurrence of CONFIG_USER_ONLY is for defining variable
tcg_use_softmmu, and we rely on dead code elimination with it in various
tcg-target.c.inc.

Thus, move its definition to tcg/tcg-internal.h, so helpers can be
included by common files. Also, change it to a define, as it has fixed
values for now.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-id: 20260219040150.2098396-8-pierrick.bouvier@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

include/tcg/tcg.h

@@ -445,12 +445,6 @@ static inline bool temp_readonly(TCGTemp *ts)
     return ts->kind >= TEMP_FIXED;
 }
 
-#ifdef CONFIG_USER_ONLY
-extern bool tcg_use_softmmu;
-#else
-#define tcg_use_softmmu  true
-#endif
-
 extern __thread TCGContext *tcg_ctx;
 extern const void *tcg_code_gen_epilogue;
 extern uintptr_t tcg_splitwx_diff;

tcg/tcg-internal.h

@@ -34,6 +34,12 @@ extern TCGContext **tcg_ctxs;
 extern unsigned int tcg_cur_ctxs;
 extern unsigned int tcg_max_ctxs;
 
+#ifdef CONFIG_USER_ONLY
+#define tcg_use_softmmu false
+#else
+#define tcg_use_softmmu true
+#endif
+
 void tcg_region_init(size_t tb_size, int splitwx, unsigned max_threads);
 bool tcg_region_alloc(TCGContext *s);
 void tcg_region_initial_alloc(TCGContext *s);

tcg/tcg.c

@@ -236,10 +236,6 @@ static TCGAtomAlign atom_and_align_for_opc(TCGContext *s, MemOp opc,
                                            MemOp host_atom, bool allow_two_ops)
     __attribute__((unused));
 
-#ifdef CONFIG_USER_ONLY
-bool tcg_use_softmmu;
-#endif
-
 TCGContext tcg_init_ctx;
 __thread TCGContext *tcg_ctx;