Update unwind.c to minimize usage of 'while (TRUE)' (#33107)

There is no need to have a "while (TRUE)" statement if we can check at the end of the loop or at the beginning.

diff --git a/src/mono/mono/mini/unwind.c b/src/mono/mono/mini/unwind.c
index 34f35da..55e2db3 100644 (file)
--- a/src/mono/mono/mini/unwind.c
+++ b/src/mono/mono/mini/unwind.c
@@ -176,18 +176,16 @@ mono_hw_reg_to_dwarf_reg (int reg)
        if (NUM_HW_REGS == 0) {
                g_assert_not_reached ();
                return -1;
-       } else {
-               return map_hw_reg_to_dwarf_reg [reg];
        }
+
+       return map_hw_reg_to_dwarf_reg [reg];
 }
 
 static void
 init_dwarf_reg_map (void)
 {
-       int i;
-
        g_assert (NUM_HW_REGS > 0);
-       for (i = 0; i < NUM_HW_REGS; ++i) {
+       for (int i = 0; i < NUM_HW_REGS; ++i) {
                map_dwarf_reg_to_hw_reg [mono_hw_reg_to_dwarf_reg (i)] = i;
        }
 
@@ -280,18 +278,18 @@ decode_sleb128 (guint8 *buf, guint8 **endbuf)
        gint32 res = 0;
        int shift = 0;
 
-       while (TRUE) {
-               guint8 b = *p;
+       guint8 b;
+
+       do {
+               b = *p;
                p ++;
 
                res = res | (((int)(b & 0x7f)) << shift);
                shift += 7;
-               if (!(b & 0x80)) {
-                       if (shift < 32 && (b & 0x40))
-                               res |= - (1 << shift);
-                       break;
-               }
-       }
+       } while (b & 0x80);
+
+       if (shift < 32 && (b & 0x40))
+               res |= - (1 << shift);
 
        *endbuf = p;
 
@@ -395,17 +393,14 @@ mono_print_unwind_info (guint8 *unwind_info, int unwind_info_len)
 guint8*
 mono_unwind_ops_encode_full (GSList *unwind_ops, guint32 *out_len, gboolean enable_extensions)
 {
-       GSList *l;
        MonoUnwindOp *op;
-       int loc;
+       int loc = 0;
        guint8 buf [4096];
        guint8 *p, *res;
 
        p = buf;
 
-       loc = 0;
-       l = unwind_ops;
-       for (; l; l = l->next) {
+       for (GSList *l = unwind_ops; l; l = l->next) {
                int reg;
 
                op = (MonoUnwindOp *)l->data;
@@ -522,11 +517,9 @@ mono_unwind_ops_encode (GSList *unwind_ops, guint32 *out_len)
 static G_GNUC_UNUSED void
 print_dwarf_state (int cfa_reg, int cfa_offset, int ip, int nregs, Loc *locations, guint8 *reg_saved)
 {
-       int i;
-
        printf ("\t%x: cfa=r%d+%d ", ip, cfa_reg, cfa_offset);
 
-       for (i = 0; i < nregs; ++i)
+       for (int i = 0; i < nregs; ++i)
                if (reg_saved [i] && locations [i].loc_type == LOC_OFFSET)
                        printf ("r%d@%d(cfa) ", i, locations [i].offset);
        printf ("\n");
@@ -732,14 +725,12 @@ mono_unwind_init (void)
 void
 mono_unwind_cleanup (void)
 {
-       int i;
-
        mono_os_mutex_destroy (&unwind_mutex);
 
        if (!cached_info)
                return;
 
-       for (i = 0; i < cached_info_next; ++i) {
+       for (int i = 0; i < cached_info_next; ++i) {
                MonoUnwindInfo *cached = cached_info [i];
 
                g_free (cached);
@@ -944,7 +935,7 @@ static void
 decode_lsda (guint8 *lsda, guint8 *code, MonoJitExceptionInfo *ex_info, gpointer *type_info, guint32 *ex_info_len, int *this_reg, int *this_offset)
 {
        guint8 *p;
-       int i, ncall_sites, this_encoding;
+       int ncall_sites, this_encoding;
        guint32 mono_magic, version;
 
        p = lsda;
@@ -980,7 +971,7 @@ decode_lsda (guint8 *lsda, guint8 *code, MonoJitExceptionInfo *ex_info, gpointer
        if (ex_info_len)
                *ex_info_len = ncall_sites;
 
-       for (i = 0; i < ncall_sites; ++i) {
+       for (int i = 0; i < ncall_sites; ++i) {
                int block_start_offset, block_size, landing_pad;
                guint8 *tinfo;
 
@@ -1167,8 +1158,7 @@ mono_unwind_decode_fde (guint8 *fde, guint32 *out_len, guint32 *code_len, MonoJi
        while (p < cie + cie_len + 4) {
                if (*p == DW_CFA_nop)
                        break;
-               else
-                       decode_cie_op (p, &p);
+               decode_cie_op (p, &p);
        }
        memcpy (buf + i, cie_cfi, p - cie_cfi);
        i += p - cie_cfi;
@@ -1177,8 +1167,7 @@ mono_unwind_decode_fde (guint8 *fde, guint32 *out_len, guint32 *code_len, MonoJi
        while (p < fde + fde_len + 4) {
                if (*p == DW_CFA_nop)
                        break;
-               else
-                       decode_cie_op (p, &p);
+               decode_cie_op (p, &p);
        }
        memcpy (buf + i, fde_cfi, p - fde_cfi);
        i += p - fde_cfi;
@@ -1256,11 +1245,8 @@ mono_unwind_decode_llvm_mono_fde (guint8 *fde, int fde_len, guint8 *cie, guint8
 
        /* Compute size of CIE unwind info it is DW_CFA_nop terminated */
        p = cie_cfi;
-       while (TRUE) {
-               if (*p == DW_CFA_nop)
-                       break;
-               else
-                       decode_cie_op (p, &p);
+       while (*p != DW_CFA_nop) {
+           decode_cie_op (p, &p);
        }
        cie_cfi_len = p - cie_cfi;
        fde_cfi_len = (fde + fde_len - fde_cfi);