Commit d05a92c9 authored by jan.koester's avatar jan.koester
Browse files

string: to_string((unsigned) long long) at full 64-bit width on ILP32 

It went through ltoa()/ultoa(), whose long is 32 bits on powerpc: storaged
reported a 160 GB disk as 1.05 GiB to webctl (RAID/LVM dialogs).

Co-Authored-By: default avatarClaude Opus 5.5 <noreply@anthropic.com>
parent fbdfa971

include/cxx/string

+14 −2
Changes for include/cxx/string: 14 added lines, 2 removed lines.
Original line number Diff line number Diff line
@@ -1621,7 +1621,19 @@ typedef string::size_type size_type; 


inline string to_string(int v) { char buf[16]; itoa(v, buf); return string(buf); }

inline string to_string(long v) { char buf[24]; ltoa(v, buf); return string(buf); }

inline string to_string(long long v) { char buf[24]; ltoa((long)v, buf); return string(buf); }

/* (unsigned) long long is 64 bits on ILP32 too: ltoa()/ultoa() take a

 * (32-bit there) long, so cutting through them truncated e.g. disk sizes

 * > 4 GiB on powerpc. Converted here at full width. */

inline string __ulltostr(unsigned long long v, bool neg) {

    char buf[24], *p = buf + sizeof buf;

    *--p = 0;

    do { *--p = (char)('0' + v % 10); v /= 10; } while (v);

    if (neg) *--p = '-';

    return string(p);

}

inline string to_string(long long v) {

    return v < 0 ? __ulltostr(0ULL - (unsigned long long)v, true) : __ulltostr((unsigned long long)v, false);

}

inline string to_string(unsigned int v) { char buf[16]; ultoa(v, buf); return string(buf); }

inline string to_string(unsigned long v) { char buf[24]; ultoa(v, buf); return string(buf); }

/* Real gap found compiling LLVM: to_string(long long) already existed
@@ -1634,7 +1646,7 @@ inline string to_string(unsigned long v) { char buf[24]; ultoa(v, buf); return s 
 * long long converts to either via an equally-ranked plain integral

 * conversion, neither promotion nor exact match) -- same lossless

 * same-width cast to unsigned long as to_string(long long)'s own. */

inline string to_string(unsigned long long v) { char buf[24]; ultoa((unsigned long)v, buf); return string(buf); }

inline string to_string(unsigned long long v) { return __ulltostr(v, false); }



/* Real gap found compiling LLVM: to_string had no floating-point

 * overloads at all -- real gap: llvm/include/llvm/Analysis/CFGPrinter.h's

src/test/e2e/CMakeLists.txt

+20 −0
Changes for src/test/e2e/CMakeLists.txt: 20 added lines, 0 removed lines.
Original line number Diff line number Diff line
@@ -3767,3 +3767,23 @@ add_test(NAME e2e_thread_reclaim COMMAND e2e_thread_reclaim) 
if(CMAKE_CROSSCOMPILING_EMULATOR)

    set_tests_properties(e2e_thread_reclaim PROPERTIES DISABLED TRUE)

endif()



add_executable(e2e_to_string_wide to_string_wide_test.cpp)

set_target_properties(e2e_to_string_wide PROPERTIES OUTPUT_NAME "to_string_wide_test")

target_compile_options(e2e_to_string_wide PRIVATE -fPIE)

target_link_options(e2e_to_string_wide PRIVATE

    -nostdlib -pie

    -Wl,--hash-style=sysv

    -Wl,--dynamic-linker,$<TARGET_FILE_DIR:systempp>/ld-linux-${CMAKE_SYSTEM_PROCESSOR}.so

    -Wl,-rpath,$<TARGET_FILE_DIR:systempp>

)

target_link_libraries(e2e_to_string_wide PRIVATE

    $<TARGET_OBJECTS:crti>

    $<TARGET_OBJECTS:Scrt1>

    $<TARGET_OBJECTS:crtbeginS>

    $<TARGET_OBJECTS:crtn>

    systempp

)

add_dependencies(e2e_to_string_wide crti Scrt1 crtbeginS crtn systempp)



add_test(NAME e2e_to_string_wide COMMAND e2e_to_string_wide)

src/test/e2e/to_string_wide_test.cpp

0 → 100644
+21 −0
Changes for src/test/e2e/to_string_wide_test.cpp: 21 added lines, 0 removed lines.
Original line number Diff line number Diff line 
/* std::to_string((unsigned) long long) must keep all 64 bits on ILP32:

 * it used to go through ltoa()/ultoa() (32-bit long on powerpc), so a

 * 160 GB disk was reported by storaged as 1.05 GiB. */



#include <string>

#include <stdio.h>



#define CHECK(cond, msg) \

    do { if (!(cond)) { printf("FAIL: %s\n", msg); return 1; } } while (0)



int main() {

    CHECK(std::to_string(160041885696LL) == "160041885696", "to_string(long long) > 4 GiB");

    CHECK(std::to_string(160041885696ULL) == "160041885696", "to_string(unsigned long long) > 4 GiB");

    CHECK(std::to_string(-160041885696LL) == "-160041885696", "to_string(long long) negative > 32 bit");

    CHECK(std::to_string((long long)(-9223372036854775807LL - 1)) == "-9223372036854775808", "to_string(LLONG_MIN)");

    CHECK(std::to_string(18446744073709551615ULL) == "18446744073709551615", "to_string(ULLONG_MAX)");

    CHECK(std::to_string(0LL) == "0" && std::to_string(0ULL) == "0", "to_string(0)");

    CHECK(std::stoll(std::to_string(-1234567890123LL)) == -1234567890123LL, "stoll(to_string()) round trip");

    printf("PASS\n");

    return 0;

}