Re: Help with clang sanitizer

[Akim Demaille]

> Le 21 sept. 2018 à 07:08, Akim Demaille <address@hidden> a écrit :
> 
> Hi all,
> 
> The CI is running the test suite with address sanitizer turned on.
> There are two failing tests:
> 
>> =================================================================
>> ==3989==ERROR: LeakSanitizer: detected memory leaks
>> Direct leak of 28 byte(s) in 1 object(s) allocated from:
>>    #0 0x527308 in operator new(unsigned long) 
>> (/home/travis/build/akimd/bison/tests/testsuite.dir/317/test+0x527308)
>>    #1 0x2b0a17ec6248 in std::string::_Rep::_S_create(unsigned long, unsigned 
>> long, std::allocator<char> const&) 
>> (/usr/lib/x86_64-linux-gnu/libstdc++.so.6+0xba248)
>>    #2 0x724e58  (<unknown module>)
>> SUMMARY: AddressSanitizer: 28 byte(s) leaked in 1 allocation(s).
>> ./types.at:128: exit code was 1, expected 0
>> 317. types.at:128: 317. lalr1.cc api.value.type=variant (types.at:128): 
>> FAILED (types.at:128)

Finally got it.  A careful reading of the test case should have
sufficed to find it :-/


commit 6537a59c98bccda8899a2fff8431071827188264
Author: Akim Demaille <address@hidden>
Date:   Sun Sep 23 11:42:56 2018 +0200

    tests: fix a memory leak
    
    This has been bugging me for while.  I was hard to reproduce: it
    worked only on GNU/Linux, probably because libc++ implements the small
    string optimization, while libstdc++ did not and actually allocated on
    the heap for this small string.
    
    See https://lists.gnu.org/archive/html/bison-patches/2018-09/msg00110.html.
    
    * tests/types.at (api.value.type): Do not provide a semantic value to
    EOF.

diff --git a/tests/types.at b/tests/types.at
index c17e852f..c95d93e4 100644
--- a/tests/types.at
+++ b/tests/types.at
@@ -132,7 +132,8 @@ m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], 
[glr.cc]],
           [],
           ['1' '2' { printf ("%2.1f\n", $1 + $2); }],
           ["12"],
-          [AT_VAL = (res - '0') / 10.0],
+          [if (res)
+             AT_VAL = (res - '0') / 10.0],
           [0.3])
 
   # A typedef which looks like a Bison keyword, but it's using braces.
@@ -141,7 +142,8 @@ m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], 
[glr.cc]],
           [%code requires { typedef double variant; }],
           ['1' '2' { printf ("%2.1f\n", $1 + $2); }],
           ["12"],
-          [AT_VAL = (res - '0') / 10.0],
+          [if (res)
+             AT_VAL = (res - '0') / 10.0],
           [0.3])
 
   # A user defined struct.
@@ -151,8 +153,11 @@ m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], 
[glr.cc]],
           ['1' '2'
              { printf ("%d %2.1f\n", $1.ival + $2.ival, $1.fval + $2.fval); }],
           ["12"],
-          [AT_VAL.ival = (res - '0') * 10;
-           AT_VAL.fval = (res - '0') / 10.f],
+          [if (res)
+             {
+               AT_VAL.ival = (res - '0') * 10;
+               AT_VAL.fval = (res - '0') / 10.f;
+             }],
           [30 0.3])
 
   # A user defined struct that uses pointers.
@@ -197,7 +202,7 @@ m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], 
[glr.cc]],
           ["12"],
           [if (res == '1')
              AT_VAL.ival = 10;
-           else
+           else if (res == '2')
              AT_VAL.fval = .2f],
           [10 0.2])
 
@@ -215,7 +220,7 @@ m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], 
[glr.cc]],
             ["12"],
             [if (res == '1')
                AT_VAL.ival = 10;
-             else
+             else if (res == '2')
                AT_VAL.fval = 0.2f],
             [10 0.2])])
 
@@ -251,7 +256,7 @@ m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], 
[glr.cc]],
           ["12"],
           [if (res == '1')
              AT_VAL.build(10);
-           else
+           else if (res == '2')
              AT_VAL.build<std::string>("two");],
           [10, two])])
 ])