Hi, I have the follow flex code using Boehm garbage collector. http://www.hboehm.info/gc/gcinterface.html
The program is compiled with the following commands. $ flex -o main.l.c main.l $ clang -I. -DGC_DEBUG -Wall -pedantic -g -c -o main.l.o main.l.c # rapidstring.h is in . $ clang main.l.o -lgc -lfl -o main.l.exe $ dsymutil main.l.exe rapidstring.h can be downloaded here. https://raw.githubusercontent.com/boyerjohn/rapidstring/master/include/rapidstring.h The following commands show that without using valgrind, the program runs OK. But if valgrind is used, the program will cause a segmentation fault. Is it because valgrind does not work with a garbage collector? $ ./main.l.exe <<EOF 1a23b 456c EOF tok = 1000, yylval= 1 tok = 1001, yylval= a tok = 1000, yylval= 23 tok = 1001, yylval= b tok = 1000, yylval= 456 tok = 1001, yylval= c $ valgrind ./main.l.exe <<EOF 1a23b 456c EOF ==44938== Memcheck, a memory error detector ==44938== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. ==44938== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright info ==44938== Command: ./main.l.exe ==44938== ==44938== Syscall param __pthread_sigmask(set) points to uninitialised byte(s) ==44938== at 0x10068CB96: __pthread_sigmask (in /usr/lib/system/libsystem_kernel.dylib) ==44938== by 0x1006C3674: pthread_sigmask (in /usr/lib/system/libsystem_pthread.dylib) ==44938== by 0x1000D0225: GC_start_mark_threads_inner (in /usr/local/Cellar/bdw-gc/8.0.2/lib/libgc.1.dylib) ==44938== by 0x1000C0060: GC_init (in /usr/local/Cellar/bdw-gc/8.0.2/lib/libgc.1.dylib) ==44938== by 0x100003133: main (main.l:33) ==44938== Address 0x1048a42e4 is on thread 1's stack ==44938== in frame #2, created by GC_start_mark_threads_inner (???:) ==44938== ==44938== Thread 2: ==44938== Invalid read of size 4 ==44938== at 0x1006C35BA: _pthread_body (in /usr/lib/system/libsystem_pthread.dylib) ==44938== by 0x1006C350C: _pthread_start (in /usr/lib/system/libsystem_pthread.dylib) ==44938== by 0x1006C2BF8: thread_start (in /usr/lib/system/libsystem_pthread.dylib) ==44938== Address 0x18 is not stack'd, malloc'd or (recently) free'd ==44938== ==44938== ==44938== Process terminating with default action of signal 11 (SIGSEGV) ==44938== Access not within mapped region at address 0x18 ==44938== at 0x1006C35BA: _pthread_body (in /usr/lib/system/libsystem_pthread.dylib) ==44938== by 0x1006C350C: _pthread_start (in /usr/lib/system/libsystem_pthread.dylib) ==44938== by 0x1006C2BF8: thread_start (in /usr/lib/system/libsystem_pthread.dylib) ==44938== If you believe this happened as a result of a stack ==44938== overflow in your program's main thread (unlikely but ==44938== possible), you can try to increase the size of the ==44938== main thread stack using the --main-stacksize= flag. ==44938== The main thread stack size used in this run was 8388608. ==44938== ==44938== HEAP SUMMARY: ==44938== in use at exit: 19,932 bytes in 162 blocks ==44938== total heap usage: 183 allocs, 21 frees, 28,380 bytes allocated ==44938== ==44938== LEAK SUMMARY: ==44938== definitely lost: 0 bytes in 0 blocks ==44938== indirectly lost: 2,064 bytes in 1 blocks ==44938== possibly lost: 0 bytes in 0 blocks ==44938== still reachable: 200 bytes in 6 blocks ==44938== suppressed: 17,668 bytes in 155 blocks ==44938== Rerun with --leak-check=full to see details of leaked memory ==44938== ==44938== For counts of detected and suppressed errors, rerun with: -v ==44938== Use --track-origins=yes to see where uninitialised values come from ==44938== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 4 from 4) Segmentation fault: 11 $ cat main.l // clang-format off %{ // clang-format on #define TOK_NUMBER 1000 #define TOK_STRING 1001 #include <gc.h> #define RS_MALLOC GC_MALLOC #define RS_REALLOC GC_REALLOC #define RS_FREE GC_FREE #include <rapidstring.h> typedef struct { int num; rapidstring str; } YYSTYPE; // clang-format off %} %option nodefault noinput nounput %option reentrant bison-bridge %% [[:digit:]]+ yylval->num=atoi(yytext); return TOK_NUMBER; [[:alpha:]]+ { // clang-format on rs_cpy(&yylval->str, yytext); return TOK_STRING; // clang-format off } .|\n %% int main() { // clang-format on GC_INIT(); yyscan_t scanner; yylex_init(&scanner); int tok; YYSTYPE lval; rs_init(&lval.str); while ((tok = yylex(&lval, scanner))) { if (tok == TOK_NUMBER) { printf("tok = %d, yylval= %d\n", tok, yyget_lval(scanner)->num); } else if (tok == TOK_STRING) { printf("tok = %d, yylval= %s\n", tok, rs_data(&yyget_lval(scanner)->str)); } } yylex_destroy(scanner); return 0; } -- Regards, Peng _______________________________________________ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
