Remove -Wno-array-bounds workaround for GCC14 compile errors

Instead launder array-tagged pointers as needed.
keirf · Jan 5, 2025 · bc655bb · bc655bb
1 parent bb9a1d7
commit bc655bb
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Showing 5 changed files with 10 additions and 6 deletions.
diff --git a/base/Rules.mk b/base/Rules.mk
@@ -23,7 +23,7 @@ FLAGS  = $(OPT_FLAGS) -nostdlib -std=gnu99 -iquote ../base/inc -fno-builtin
 FLAGS += -Wall -Werror -Wno-format -Wdeclaration-after-statement
 FLAGS += -Wstrict-prototypes -Wredundant-decls -Wnested-externs
 FLAGS += -fno-common -fno-exceptions -fno-strict-aliasing -fomit-frame-pointer
-FLAGS += -fno-delete-null-pointer-checks -Wno-array-bounds -m68000 -msoft-float
+FLAGS += -fno-delete-null-pointer-checks -m68000 -msoft-float
 
 FLAGS += -MMD -MF .$(@F).d
 DEPS = .*.d

diff --git a/base/inc/util.h b/base/inc/util.h
@@ -21,6 +21,9 @@
 
 #define barrier() asm volatile("" ::: "memory")
 
+/* Suppresses unwanted array-bounds compiler warnings. */
+#define arrayptr_launder(x) ({ typeof(x) _x; asm("":"=r"(_x):"0"(x)); _x; })
+
 #ifndef offsetof
 #define offsetof(a,b) __builtin_offsetof(a,b)
 #endif

diff --git a/cracking/cracks/nzs/Rules.mk b/cracking/cracks/nzs/Rules.mk
@@ -10,7 +10,7 @@ FLAGS  = -Os -nostdlib -std=gnu99 -iquote inc
 FLAGS += -Wall -Werror -Wno-format -Wdeclaration-after-statement
 FLAGS += -Wstrict-prototypes -Wredundant-decls -Wnested-externs
 FLAGS += -fno-common -fno-exceptions -fno-strict-aliasing -fomit-frame-pointer
-FLAGS += -fno-delete-null-pointer-checks -Wno-array-bounds -m68000 -msoft-float
+FLAGS += -fno-delete-null-pointer-checks -m68000 -msoft-float
 
 FLAGS += -MMD -MF .$(@F).d
 DEPS = .*.d

diff --git a/testkit/crash.c b/testkit/crash.c
@@ -99,13 +99,14 @@ struct frame {
 /* Fix up one 68000 unrecoverable fault handler. */
 static void fixup_68000(void *new_fn, volatile uint32_t *vec)
 {
-    uint32_t old_fn = *vec;
+    volatile uint32_t *_vec = arrayptr_launder(vec);
+    uint32_t old_fn = *_vec;
     /* Search for the JMP instruction in the shim handler, and patch it. */
     uint16_t *p = new_fn;
     while (*p != 0x4ef9) p++;
     *(uint32_t *)(p+1) = old_fn;
     /* Install our shim handler. */
-    *vec = (uint32_t)new_fn;
+    *_vec = (uint32_t)new_fn;
 }
 
 /* 68000 (only) has weird stack formats for unrecoverable faults. These cause 

diff --git a/testkit/memory.c b/testkit/memory.c
@@ -424,15 +424,15 @@ static void memcheck_direct_scan(void)
     for (i = 0; i < 27; i++) {
         if (aliased_slots & (1u << i))
             continue;
-        p = (volatile uint16_t *)&s[0] + (i << 18);
+        p = (volatile uint16_t *)arrayptr_launder(&s[0]) + (i << 18);
         p[0] = 0x5555;
         p[1<<17] = 0xaaaa;
         if ((p[0] != 0x5555) || (p[1<<17] != 0xaaaa)) {
             p[0] = p[1<<17] = 0;
             continue;
         }
         for (j = 0; j < i; j++) {
-            q = (volatile uint16_t *)s + (j << 18);
+            q = (volatile uint16_t *)arrayptr_launder(&s[0]) + (j << 18);
             if ((ram_slots & (1u << j)) && (*q == 0x5555))
                 break;
         }