runtime: adapt to -Werror=implicit-fallthrough=5

Linux kbuild commit d936eb23874 sets $subject CFLAGS, so to play
catch-up, we also need to use gcc attribute(fallthrough) to label such
spots in switch() statements in our runtime / tapset.  Tested on
linux5.14 gcc11 rawhide and linux3.10 gcc4 rhel7.

diff --git a/runtime/linux/runtime.h b/runtime/linux/runtime.h
index 035f0bd97698a7186a697d5c26e7c1d9cb48cd74..e57d10a8a09ce7cbd4b6d311cf0174865b6866e5 100644 (file)
--- a/runtime/linux/runtime.h
+++ b/runtime/linux/runtime.h
@@ -65,6 +65,22 @@
 static void *kallsyms_copy_to_kernel_nofault;
 #endif
 
+
+/* A fallthrough; macro to let the runtime survive -Wimplicit-fallthrough=5 */
+/* from <linux/compiler_attribute.h> */
+#ifndef fallthrough
+#if __GNUC__ < 5
+# define fallthrough                    do {} while (0)  /* fallthrough */
+#else
+#if __has_attribute(__fallthrough__)
+# define fallthrough                    __attribute__((__fallthrough__))
+#else
+# define fallthrough                    do {} while (0)  /* fallthrough */
+#endif
+#endif
+#endif
+
+
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,23)
 #include <linux/user_namespace.h>
 #endif

diff --git a/runtime/map-gen.c b/runtime/map-gen.c
index aeeab38bf1153dd0499bfef550000fbdf20614e6..47317d61f98b1e4d46770d6f12a3e2ec05b93924 100644 (file)
--- a/runtime/map-gen.c
+++ b/runtime/map-gen.c
@@ -112,9 +112,9 @@
                 k1 = 0; \
                 switch(mylen & 3) {                \
                 case 3: k1 ^= tail[2] << 16; \
-                        /* fallthrough */ \
+                        fallthrough; \
                 case 2: k1 ^= tail[1] << 8; \
-                        /* fallthrough */ \
+                        fallthrough; \
                 case 1: k1 ^= tail[0]; \
                         k1 *= c1; k1 = ROTL32(k1,15); k1 *= c2; h1 ^= k1; \
                 } \

diff --git a/runtime/syscall.h b/runtime/syscall.h
index 6b4b3071a7240f67c60aaa40003bc6314f7459f8..f5b473b04efa3bc1cc4a04b0512bd6b9b6567392 100644 (file)
--- a/runtime/syscall.h
+++ b/runtime/syscall.h
@@ -351,23 +351,23 @@ _stp_syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
                case 0:
                        if (!n--) break;
                        *args++ = regs->bx;
-                       /* fallthrough */
+                        fallthrough;
                case 1:
                        if (!n--) break;
                        *args++ = regs->cx;
-                       /* fallthrough */
+                        fallthrough;
                case 2:
                        if (!n--) break;
                        *args++ = regs->dx;
-                       /* fallthrough */
+                        fallthrough;
                case 3:
                        if (!n--) break;
                        *args++ = regs->si;
-                       /* fallthrough */
+                        fallthrough;
                case 4:
                        if (!n--) break;
                        *args++ = regs->di;
-                       /* fallthrough */
+                        fallthrough;
                case 5:
                        if (!n--) break;
                        *args++ = regs->bp;
@@ -375,23 +375,23 @@ _stp_syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
                case 0:
                        if (!n--) break;
                        *args++ = regs->rbx;
-                       /* fallthrough */
+                        fallthrough;
                case 1:
                        if (!n--) break;
                        *args++ = regs->rcx;
-                       /* fallthrough */
+                        fallthrough;
                case 2:
                        if (!n--) break;
                        *args++ = regs->rdx;
-                       /* fallthrough */
+                        fallthrough;
                case 3:
                        if (!n--) break;
                        *args++ = regs->rsi;
-                       /* fallthrough */
+                        fallthrough;
                case 4:
                        if (!n--) break;
                        *args++ = regs->rdi;
-                       /* fallthrough */
+                        fallthrough;
                case 5:
                        if (!n--) break;
                        *args++ = regs->rbp;
@@ -405,23 +405,23 @@ _stp_syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
        case 0:
                if (!n--) break;
                *args++ = regs->di;
-               /* fallthrough */
+                fallthrough;
        case 1:
                if (!n--) break;
                *args++ = regs->si;
-               /* fallthrough */
+                fallthrough;
        case 2:
                if (!n--) break;
                *args++ = regs->dx;
-               /* fallthrough */
+                fallthrough;
        case 3:
                if (!n--) break;
                *args++ = regs->r10;
-               /* fallthrough */
+                fallthrough;
        case 4:
                if (!n--) break;
                *args++ = regs->r8;
-               /* fallthrough */
+                fallthrough;
        case 5:
                if (!n--) break;
                *args++ = regs->r9;
@@ -429,23 +429,23 @@ _stp_syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
        case 0:
                if (!n--) break;
                *args++ = regs->rdi;
-               /* fallthrough */
+                fallthrough;
        case 1:
                if (!n--) break;
                *args++ = regs->rsi;
-               /* fallthrough */
+                fallthrough;
        case 2:
                if (!n--) break;
                *args++ = regs->rdx;
-               /* fallthrough */
+                fallthrough;
        case 3:
                if (!n--) break;
                *args++ = regs->r10;
-               /* fallthrough */
+                fallthrough;
        case 4:
                if (!n--) break;
                *args++ = regs->r8;
-               /* fallthrough */
+                fallthrough;
        case 5:
                if (!n--) break;
                *args++ = regs->r9;
@@ -575,30 +575,30 @@ static inline void _stp_syscall_get_arguments(struct task_struct *task,
                case 6:
                        if (!n--) break;
                        *args++ = regs->r13;
-                       /* fallthrough */
+                       fallthrough;
                case 5:
                        if (!n--) break;
                        *args++ = regs->r15;
-                       /* fallthrough */
+                       fallthrough;
                case 4:
                        if (!n--) break;
                        *args++ = regs->r14;
-                       /* fallthrough */
+                       fallthrough;
                case 3:
                        if (!n--) break;
                        *args++ = regs->r10;
-                       /* fallthrough */
+                       fallthrough;
                case 2:
                        if (!n--) break;
                        *args++ = regs->r9;
-                       /* fallthrough */
+                       fallthrough;
                case 1:
                        if (!n--) break;
                        *args++ = regs->r11;
-                       /* fallthrough */
+                       fallthrough;
                case 0:
                        if (!n--) break;
-                       /* fallthrough */
+                       fallthrough;
                default:
                        BUG();
                        break;
@@ -630,23 +630,23 @@ _stp_syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
        case 0:
                if (!n--) break;
                *args++ = regs->orig_gpr2 & mask;
-               /* fallthrough */
+               fallthrough;
        case 1:
                if (!n--) break;
                *args++ = regs->gprs[3] & mask;
-               /* fallthrough */
+               fallthrough;
        case 2:
                if (!n--) break;
                *args++ = regs->gprs[4] & mask;
-               /* fallthrough */
+               fallthrough;
        case 3:
                if (!n--) break;
                *args++ = regs->gprs[5] & mask;
-               /* fallthrough */
+               fallthrough;
        case 4:
                if (!n--) break;
                *args++ = regs->gprs[6] & mask;
-               /* fallthrough */
+               fallthrough;
        case 5:
                if (!n--) break;
                *args++ = regs->args[0] & mask;

diff --git a/runtime/unwind.c b/runtime/unwind.c
index dba16a7246183f526398f410b2088262c72afd28..6916d2e96ca1e08da21884951f55884ef77344e1 100644 (file)
--- a/runtime/unwind.c
+++ b/runtime/unwind.c
@@ -527,7 +527,7 @@ static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc,
                                        REG_STATE.cfa.reg = value;
                                        dbug_unwind(1, "DW_CFA_def_cfa reg=%ld\n", REG_STATE.cfa.reg);
                                }
-                               /* fallthrough */
+                               fallthrough;
                        case DW_CFA_def_cfa_offset:
                                if (REG_STATE.cfa_is_expr != 0) {
                                        _stp_warn("Unexpected DW_CFA_def_cfa_offset\n");
@@ -549,7 +549,7 @@ static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc,
                                                    value, DWARF_REG_MAP(value));
                                        REG_STATE.cfa.reg = value;
                                }
-                               /* fallthrough */
+                               fallthrough;
                        case DW_CFA_def_cfa_offset_sf:
                                if (REG_STATE.cfa_is_expr != 0) {
                                        _stp_warn("Unexpected DW_CFA_def_cfa_offset_sf\n");
@@ -922,7 +922,7 @@ static int compute_expr(const u8 *expr, struct unwind_frame_info *frame,
                case DW_OP_bra:
                        if (POP == 0)
                                break;
-                       /* Fall through.  */
+                        fallthrough;
                case DW_OP_skip:
                        NEED(sizeof(u.s16));
                        memcpy(&u.s16, expr, sizeof(u.s16));

diff --git a/runtime/unwind/unwind.h b/runtime/unwind/unwind.h
index a9586a3383c804df03475f18e5ed00a9be10bcc4..5c68a5f033b8a35d045e1e64d19d878af5d1dd8e 100644 (file)
--- a/runtime/unwind/unwind.h
+++ b/runtime/unwind/unwind.h
@@ -154,13 +154,13 @@ static unsigned long read_ptr_sect(const u8 **pLoc, const void *end,
                                value = _stp_get_unaligned(ptr.p32u++);
                        break;
                }
-               /* fallthrough */
+                fallthrough;
        case DW_EH_PE_data8:
                BUILD_BUG_ON(sizeof(u64) != sizeof(value));
 #else
                BUILD_BUG_ON(sizeof(u32) != sizeof(value));
 #endif
-               /* fallthrough */
+                fallthrough;
        case DW_EH_PE_absptr:
                if (compat_task)
                {

diff --git a/runtime/vsprintf.c b/runtime/vsprintf.c
index 417d9f7f37eed3f0da237615669d1a6a6e01a786..cd31a938b78e1d3bf713f673f6d26df9d21935d8 100644 (file)
--- a/runtime/vsprintf.c
+++ b/runtime/vsprintf.c
@@ -641,7 +641,7 @@ _stp_vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 
                     case 'X':
                             flags |= STP_LARGE;
-                           /* fallthru */
+                           fallthrough;
                     case 'x':
                             base = 16;
                             break;
@@ -649,7 +649,7 @@ _stp_vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
                     case 'd':
                     case 'i':
                             flags |= STP_SIGN;
-                           /* fallthru */
+                           fallthrough;
                     case 'u':
                             break;
 
@@ -835,7 +835,7 @@ _stp_vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 
                case 'X':
                        flags |= STP_LARGE;
-                       /* fallthru */
+                        fallthrough;
                case 'x':
                        base = 16;
                        break;
@@ -843,7 +843,7 @@ _stp_vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
                case 'd':
                case 'i':
                        flags |= STP_SIGN;
-                       /* fallthru */
+                        fallthrough;
                case 'u':
                        break;
 

diff --git a/tapset/linux/aux_syscalls.stp b/tapset/linux/aux_syscalls.stp
index ad8a89898d4c6270935b34bca243aee34cbe16f3..09fb9ff41e8cc8acce060bfc2a08a66f54b94237 100644 (file)
--- a/tapset/linux/aux_syscalls.stp
+++ b/tapset/linux/aux_syscalls.stp
@@ -156,11 +156,11 @@ sigset_from_compat(sigset_t *set, compat_sigset_t *compat)
 {
        switch (_NSIG_WORDS) {
        case 4: set->sig[3] = compat->sig[6] | (((long)compat->sig[7]) << 32 );
-         /*fallthrough*/
+          fallthrough;
        case 3: set->sig[2] = compat->sig[4] | (((long)compat->sig[5]) << 32 );
-         /*fallthrough*/
+          fallthrough;
        case 2: set->sig[1] = compat->sig[2] | (((long)compat->sig[3]) << 32 );
-         /*fallthrough*/
+          fallthrough;
        case 1: set->sig[0] = compat->sig[0] | (((long)compat->sig[1]) << 32 );
        }
 }
@@ -3627,13 +3627,13 @@ function _struct_sigaction32_u:string(uaddr:long)
            {
            case 4: act.sa_mask.sig[3] = act32.sa_mask.sig[6]
                | (((long)act32.sa_mask.sig[7]) << 32);
-             /* fallthrough */
+              fallthrough;
            case 3: act.sa_mask.sig[2] = act32.sa_mask.sig[4]
                | (((long)act32.sa_mask.sig[5]) << 32);
-             /* fallthrough */
+              fallthrough;
            case 2: act.sa_mask.sig[1] = act32.sa_mask.sig[2]
                | (((long)act32.sa_mask.sig[3]) << 32);
-             /* fallthrough */
+              fallthrough;
            case 1: act.sa_mask.sig[0] = act32.sa_mask.sig[0]
                | (((long)act32.sa_mask.sig[1]) << 32);
            }