binout: reinstate checks for truncated values

tools/common/binout.c

@@ -18,18 +18,18 @@ struct {
 	struct placeholder_data value;
 } *placeholder_hash = NULL;
 
-void w8(FILE *f, uint8_t v) 
+void _w8(FILE *f, uint8_t v) 
 {
     fputc(v, f);
 }
 
-void w16(FILE *f, uint16_t v)
+void _w16(FILE *f, uint16_t v)
 {
     w8(f, v >> 8);
     w8(f, v & 0xff);
 }
 
-void w32(FILE *f, uint32_t v)
+void _w32(FILE *f, uint32_t v)
 {
     w16(f, v >> 16);
     w16(f, v & 0xffff);

tools/common/binout.h

@@ -14,6 +14,18 @@
 
 #define BITCAST_F2I(f)   ({ uint32_t __i; float __f = (f); memcpy(&__i, &(__f), 4); __i; })
 
+#define _wconv(type, v) ({ \
+    typeof(v) _v = (v); \
+    if (sizeof(type) < sizeof(_v)) { \
+        int64_t ext = (int64_t)_v >> (sizeof(type) * 8); \
+        if (ext != 0 && ext != (uint64_t)-1) { \
+            fprintf(stderr, "fatal: truncating value %lld to %s (ext=%lld)\n", (long long)_v, #type, ext); \
+            assert(ext == 0 || ext == (uint64_t)-1); \
+        } \
+    } \
+    (type)_v; \
+})
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -24,10 +36,13 @@ void placeholder_setv_offset(FILE *file, int offset, const char *format, va_list
 void placeholder_set_offset(FILE *file, int offset, const char *format, ...);
 void placeholder_clear();
 
-void w8(FILE *f, uint8_t v);
-void w16(FILE *f, uint16_t v);
-void w32(FILE *f, uint32_t v);
-#define wf32(f, v) w32(f, BITCAST_F2I(v))
+void _w8(FILE *f, uint8_t v);
+void _w16(FILE *f, uint16_t v);
+void _w32(FILE *f, uint32_t v);
+#define w8(f, v) _w8(f, _wconv(uint8_t, v))
+#define w16(f, v) _w16(f, _wconv(uint16_t, v))
+#define w32(f, v) _w32(f, _wconv(uint32_t, v))
+#define wf32(f, v) _w32(f, BITCAST_F2I(v))
 #define wf32approx(f, v, prec) wf32(f, roundf((v)/(prec))*(prec))
 
 int w32_placeholder(FILE *f);