target/i386: Mark some helpers as noreturn

Any helper that always raises an exception or interrupt,
or simply exits to the main loop, can be so marked.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210514151342.384376-35-richard.henderson@linaro.org>

5 files changed, 29 insertions, 26 deletions

diff --git a/target/i386/helper.h b/target/i386/helper.h
index d0f7f07c6c..f794d1c7c7 100644
--- a/target/i386/helper.h
+++ b/target/i386/helper.h
@@ -60,14 +60,14 @@ DEF_HELPER_2(sysexit, void, env, int)
 DEF_HELPER_2(syscall, void, env, int)
 DEF_HELPER_2(sysret, void, env, int)
 #endif
-DEF_HELPER_2(hlt, void, env, int)
-DEF_HELPER_2(monitor, void, env, tl)
-DEF_HELPER_2(mwait, void, env, int)
-DEF_HELPER_2(pause, void, env, int)
-DEF_HELPER_1(debug, void, env)
+DEF_HELPER_FLAGS_2(hlt, TCG_CALL_NO_WG, noreturn, env, int)
+DEF_HELPER_FLAGS_2(monitor, TCG_CALL_NO_WG, void, env, tl)
+DEF_HELPER_FLAGS_2(mwait, TCG_CALL_NO_WG, noreturn, env, int)
+DEF_HELPER_FLAGS_2(pause, TCG_CALL_NO_WG, noreturn, env, int)
+DEF_HELPER_FLAGS_1(debug, TCG_CALL_NO_WG, noreturn, env)
 DEF_HELPER_1(reset_rf, void, env)
-DEF_HELPER_3(raise_interrupt, void, env, int, int)
-DEF_HELPER_2(raise_exception, void, env, int)
+DEF_HELPER_FLAGS_3(raise_interrupt, TCG_CALL_NO_WG, noreturn, env, int, int)
+DEF_HELPER_FLAGS_2(raise_exception, TCG_CALL_NO_WG, noreturn, env, int)
 DEF_HELPER_1(cli, void, env)
 DEF_HELPER_1(sti, void, env)
 DEF_HELPER_1(clac, void, env)
@@ -86,12 +86,12 @@ DEF_HELPER_2(cmpxchg8b, void, env, tl)
 DEF_HELPER_2(cmpxchg16b_unlocked, void, env, tl)
 DEF_HELPER_2(cmpxchg16b, void, env, tl)
 #endif
-DEF_HELPER_1(single_step, void, env)
+DEF_HELPER_FLAGS_1(single_step, TCG_CALL_NO_WG, noreturn, env)
 DEF_HELPER_1(rechecking_single_step, void, env)
 DEF_HELPER_1(cpuid, void, env)
 DEF_HELPER_1(rdtsc, void, env)
 DEF_HELPER_1(rdtscp, void, env)
-DEF_HELPER_1(rdpmc, void, env)
+DEF_HELPER_FLAGS_1(rdpmc, TCG_CALL_NO_WG, noreturn, env)
 DEF_HELPER_1(rdmsr, void, env)
 DEF_HELPER_1(wrmsr, void, env)
 
diff --git a/target/i386/tcg/bpt_helper.c b/target/i386/tcg/bpt_helper.c
index fb2a65ac9c..83cd89581e 100644
--- a/target/i386/tcg/bpt_helper.c
+++ b/target/i386/tcg/bpt_helper.c
@@ -22,7 +22,7 @@
 #include "exec/helper-proto.h"
 #include "helper-tcg.h"
 
-void helper_single_step(CPUX86State *env)
+void QEMU_NORETURN helper_single_step(CPUX86State *env)
 {
 #ifndef CONFIG_USER_ONLY
     check_hw_breakpoints(env, true);
diff --git a/target/i386/tcg/excp_helper.c b/target/i386/tcg/excp_helper.c
index 0183f3932e..bdae887d0a 100644
--- a/target/i386/tcg/excp_helper.c
+++ b/target/i386/tcg/excp_helper.c
@@ -25,12 +25,13 @@
 #include "exec/helper-proto.h"
 #include "helper-tcg.h"
 
-void helper_raise_interrupt(CPUX86State *env, int intno, int next_eip_addend)
+void QEMU_NORETURN helper_raise_interrupt(CPUX86State *env, int intno,
+                                          int next_eip_addend)
 {
     raise_interrupt(env, intno, 1, 0, next_eip_addend);
 }
 
-void helper_raise_exception(CPUX86State *env, int exception_index)
+void QEMU_NORETURN helper_raise_exception(CPUX86State *env, int exception_index)
 {
     raise_exception(env, exception_index);
 }
@@ -116,24 +117,25 @@ void QEMU_NORETURN raise_interrupt(CPUX86State *env, int intno, int is_int,
     raise_interrupt2(env, intno, is_int, error_code, next_eip_addend, 0);
 }
 
-void raise_exception_err(CPUX86State *env, int exception_index,
-                         int error_code)
+void QEMU_NORETURN raise_exception_err(CPUX86State *env, int exception_index,
+                                       int error_code)
 {
     raise_interrupt2(env, exception_index, 0, error_code, 0, 0);
 }
 
-void raise_exception_err_ra(CPUX86State *env, int exception_index,
-                            int error_code, uintptr_t retaddr)
+void QEMU_NORETURN raise_exception_err_ra(CPUX86State *env, int exception_index,
+                                          int error_code, uintptr_t retaddr)
 {
     raise_interrupt2(env, exception_index, 0, error_code, 0, retaddr);
 }
 
-void raise_exception(CPUX86State *env, int exception_index)
+void QEMU_NORETURN raise_exception(CPUX86State *env, int exception_index)
 {
     raise_interrupt2(env, exception_index, 0, 0, 0, 0);
 }
 
-void raise_exception_ra(CPUX86State *env, int exception_index, uintptr_t retaddr)
+void QEMU_NORETURN raise_exception_ra(CPUX86State *env, int exception_index,
+                                      uintptr_t retaddr)
 {
     raise_interrupt2(env, exception_index, 0, 0, 0, retaddr);
 }
diff --git a/target/i386/tcg/misc_helper.c b/target/i386/tcg/misc_helper.c
index a30379283e..0e9a4f0bfc 100644
--- a/target/i386/tcg/misc_helper.c
+++ b/target/i386/tcg/misc_helper.c
@@ -96,7 +96,7 @@ void helper_rdtscp(CPUX86State *env)
     env->regs[R_ECX] = (uint32_t)(env->tsc_aux);
 }
 
-void helper_rdpmc(CPUX86State *env)
+void QEMU_NORETURN helper_rdpmc(CPUX86State *env)
 {
     if (((env->cr[4] & CR4_PCE_MASK) == 0 ) &&
         ((env->hflags & HF_CPL_MASK) != 0)) {
@@ -109,7 +109,7 @@ void helper_rdpmc(CPUX86State *env)
     raise_exception_err(env, EXCP06_ILLOP, 0);
 }
 
-static void do_pause(X86CPU *cpu)
+static QEMU_NORETURN void do_pause(X86CPU *cpu)
 {
     CPUState *cs = CPU(cpu);
 
@@ -118,7 +118,7 @@ static void do_pause(X86CPU *cpu)
     cpu_loop_exit(cs);
 }
 
-static void do_hlt(X86CPU *cpu)
+static QEMU_NORETURN void do_hlt(X86CPU *cpu)
 {
     CPUState *cs = CPU(cpu);
     CPUX86State *env = &cpu->env;
@@ -129,7 +129,7 @@ static void do_hlt(X86CPU *cpu)
     cpu_loop_exit(cs);
 }
 
-void helper_hlt(CPUX86State *env, int next_eip_addend)
+void QEMU_NORETURN helper_hlt(CPUX86State *env, int next_eip_addend)
 {
     X86CPU *cpu = env_archcpu(env);
 
@@ -148,7 +148,7 @@ void helper_monitor(CPUX86State *env, target_ulong ptr)
     cpu_svm_check_intercept_param(env, SVM_EXIT_MONITOR, 0, GETPC());
 }
 
-void helper_mwait(CPUX86State *env, int next_eip_addend)
+void QEMU_NORETURN helper_mwait(CPUX86State *env, int next_eip_addend)
 {
     CPUState *cs = env_cpu(env);
     X86CPU *cpu = env_archcpu(env);
@@ -167,7 +167,7 @@ void helper_mwait(CPUX86State *env, int next_eip_addend)
     }
 }
 
-void helper_pause(CPUX86State *env, int next_eip_addend)
+void QEMU_NORETURN helper_pause(CPUX86State *env, int next_eip_addend)
 {
     X86CPU *cpu = env_archcpu(env);
 
@@ -177,7 +177,7 @@ void helper_pause(CPUX86State *env, int next_eip_addend)
     do_pause(cpu);
 }
 
-void helper_debug(CPUX86State *env)
+void QEMU_NORETURN helper_debug(CPUX86State *env)
 {
     CPUState *cs = env_cpu(env);
 
diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index b2a997fb30..c1d4d58c61 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -7282,6 +7282,7 @@ static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
         gen_update_cc_op(s);
         gen_jmp_im(s, pc_start - s->cs_base);
         gen_helper_rdpmc(cpu_env);
+        s->base.is_jmp = DISAS_NORETURN;
         break;
     case 0x134: /* sysenter */
         /* For Intel SYSENTER is valid on 64-bit */
@@ -7443,7 +7444,7 @@ static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
             gen_update_cc_op(s);
             gen_jmp_im(s, pc_start - s->cs_base);
             gen_helper_mwait(cpu_env, tcg_const_i32(s->pc - pc_start));
-            gen_eob(s);
+            s->base.is_jmp = DISAS_NORETURN;
             break;
 
         case 0xca: /* clac */