Resolve warnings on aarch64

[phillipjohnston]

The following warnings are generated in Clang when compiling with an aarch64 cross-file:

12:22:27 {pj/demo} libc$ make
[35/532] Compiling C object 'src/e88f707@@printf@sta/.._printf_printf.c.o'.
../printf/printf.c:493:28: warning: shift count >= width of type [-Wshift-count-overflow]
  int exp2 = (int)((conv.U >> 52U) & 0x07FFU) - 1023;           // effectively log2
                           ^  ~~~
../printf/printf.c:501:36: warning: shift count >= width of type [-Wshift-count-overflow]
  conv.U = (uint64_t)(exp2 + 1023) << 52U;
                                   ^  ~~~
2 warnings generated.
[100/532] Compiling C object 'src/e88f707@@c@sta/stdlib_strtol.c.o'.
../src/stdlib/strtol.c:158:44: warning: implicit conversion from 'long long' to 'unsigned long' changes value from 9223372036854775807 to 4294967295 [-Wconstant-conversion]
        cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
               ~                                  ^~~~~~~~
../arch/aarch64/include/_limits.h:5:18: note: expanded from macro 'LONG_MAX'
#define LONG_MAX 0x7fffffffffffffffL
                 ^~~~~~~~~~~~~~~~~~~
1 warning generated.
[102/532] Compiling C object 'src/e88f707@@c@sta/stdlib_strtoul.c.o'.
../src/stdlib/strtoul.c:126:26: warning: overflow in expression; result is -2 with type 'long long' [-Winteger-overflow]
        cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
                                ^
../include/limits.h:61:24: note: expanded from macro 'ULONG_MAX'
#define ULONG_MAX (2UL * LONG_MAX + 1)
                       ^
../src/stdlib/strtoul.c:127:32: warning: overflow in expression; result is -2 with type 'long long' [-Winteger-overflow]
        cutlim = (int)((unsigned long)ULONG_MAX % (unsigned long)base);
                                      ^
../include/limits.h:61:24: note: expanded from macro 'ULONG_MAX'
#define ULONG_MAX (2UL * LONG_MAX + 1)
                       ^
../src/stdlib/strtoul.c:161:9: warning: overflow in expression; result is -2 with type 'long long' [-Winteger-overflow]
                acc = ULONG_MAX;
                      ^
../include/limits.h:61:24: note: expanded from macro 'ULONG_MAX'
#define ULONG_MAX (2UL * LONG_MAX + 1)
                       ^
3 warnings generated.
[127/532] Compiling C object 'src/e88f707@@c@sta/string_strlen.c.o'.
../src/string/strlen.c:58:37: warning: implicit conversion from 'long long' to 'unsigned long' changes value from 72340172838076673 to 16843009 [-Wconstant-conversion]
static const unsigned long mask01 = 0x0101010101010101;
                           ~~~~~~   ^~~~~~~~~~~~~~~~~~
../src/string/strlen.c:59:37: warning: implicit conversion from 'unsigned long long' to 'unsigned long' changes value from 9259542123273814144 to 2155905152 [-Wconstant-conversion]
static const unsigned long mask80 = 0x8080808080808080;
                           ~~~~~~   ^~~~~~~~~~~~~~~~~~
2 warnings generated.
[396/532] Compiling C object 'src/e88f707@@c_hosted@sta/stdlib_strtol.c.o'.
../src/stdlib/strtol.c:158:44: warning: implicit conversion from 'long long' to 'unsigned long' changes value from 9223372036854775807 to 4294967295 [-Wconstant-conversion]
        cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
               ~                                  ^~~~~~~~
../arch/aarch64/include/_limits.h:5:18: note: expanded from macro 'LONG_MAX'
#define LONG_MAX 0x7fffffffffffffffL
                 ^~~~~~~~~~~~~~~~~~~
1 warning generated.
[397/532] Compiling C object 'src/e88f707@@c_hosted@sta/stdlib_strtoul.c.o'.
../src/stdlib/strtoul.c:126:26: warning: overflow in expression; result is -2 with type 'long long' [-Winteger-overflow]
        cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
                                ^
../include/limits.h:61:24: note: expanded from macro 'ULONG_MAX'
#define ULONG_MAX (2UL * LONG_MAX + 1)
                       ^
../src/stdlib/strtoul.c:127:32: warning: overflow in expression; result is -2 with type 'long long' [-Winteger-overflow]
        cutlim = (int)((unsigned long)ULONG_MAX % (unsigned long)base);
                                      ^
../include/limits.h:61:24: note: expanded from macro 'ULONG_MAX'
#define ULONG_MAX (2UL * LONG_MAX + 1)
                       ^
../src/stdlib/strtoul.c:161:9: warning: overflow in expression; result is -2 with type 'long long' [-Winteger-overflow]
                acc = ULONG_MAX;
                      ^
../include/limits.h:61:24: note: expanded from macro 'ULONG_MAX'
#define ULONG_MAX (2UL * LONG_MAX + 1)
                       ^
3 warnings generated.
[423/532] Compiling C object 'src/e88f707@@c_hosted@sta/string_strlen.c.o'.
../src/string/strlen.c:58:37: warning: implicit conversion from 'long long' to 'unsigned long' changes value from 72340172838076673 to 16843009 [-Wconstant-conversion]
static const unsigned long mask01 = 0x0101010101010101;
                           ~~~~~~   ^~~~~~~~~~~~~~~~~~
../src/string/strlen.c:59:37: warning: implicit conversion from 'unsigned long long' to 'unsigned long' changes value from 9259542123273814144 to 2155905152 [-Wconstant-conversion]
static const unsigned long mask80 = 0x8080808080808080;
                           ~~~~~~   ^~~~~~~~~~~~~~~~~~
2 warnings generated.

[eyalroz]

Well, this libc uses mpaland/printf; these warnings, along with many actual bugs and even a case of undefined behavior, are all resolved in the unified fork I've been working on. See also issue #159 where I suggested adopting it.

[phillipjohnston]

Just noting for my future self: the first warning is printf, but the rest are problems within libc for aarch64

[phillipjohnston]

Resolved all of these.