I believe they are legal. Although the exact behavior for the first one is debatable (should (*x)++ side effect be reflected?). I haven't got exact answer on the first case yet, but the current implementation is the same as gcc's.
Sincerely ------------------------------- Feng Zhou On Thu, Jan 20, 2011 at 12:25 PM, Handong Ye <yehand...@gmail.com> wrote: > Hi Feng, where is the test case from? > Why people create such weird code? > Is it a legal one? > > Handong > > On Thu, Jan 20, 2011 at 9:09 AM, Feng Zhou <fengzho...@gmail.com> wrote: >> Hello, all >> >> Attached is my fix for bug >> #585(https://bugs.open64.net/show_bug.cgi?id=585). There are three >> test cases attached to the bug report. They all experience same >> problem: compile time segmentation fault at wgen phase. However, each >> of them is caused by a different problem. >> >> pr22061-2.c >> =========== >> The test case is shown below: >> >> int *x; >> static void bar (char a[2][(*x)++]) {} >> >> The problem is that when generating type information for bar function, >> (*x)++ needs to be expanded since `a` is a variable length array. >> However, current wgen assumes that WHIRL node for current function >> (`Current_Entry_Wn()`) already exists. However, this is not true at >> the time of generating function type information. >> >> crash2.C >> ======== >> The part of code causing problems is shown below: >> >> R1::R1( const R& a ) : >> m_( a.empty() ? get_empty().m_ : C() ) >> >> The gspin expression for the select is organized as follows: >> >> COND_EXPR >> |-- COND >> |-- TARGET_EXPR >> |-- COMPONENT_REF (S1) >> |-- INDIRECT_REF >> |-- ... >> |-- COMPONENT_REF (S2) >> |-- TARGET_REF >> |-- ... >> |-- ... >> >> S1 is actually a VAR_DECL expression in gspin file. It is changed to >> COMPONENT_REF when converting COND_EXPR (see wgen_expr.cxx:6056, added >> for bug 15210). However, the presence of INDIRECT_REF causes target >> symbol being NULL and this caused segmentation fault in WN_Lda >> function. >> >> ftp.i >> ===== >> The following code snippet caused the problem: >> >> struct string { >> unsigned char *source; >> }; >> struct ftp_file_info { >> struct string name; >> struct string symlink; >> long size; >> time_t mtime; >> unsigned int local_time_zone:1; >> mode_t permissions; >> }; >> static int ftp_process_dirlist() >> { >> int ret = 0; >> while (1) { >> struct ftp_file_info ftp_info = { FTP_FILE_UNKNOWN, {"", 0}, >> {"", 0}, -1, 0, 0 }; >> } >> } >> >> The compiler tries to generate initialization code for each field of >> `ftp_info`. For each field, `Advance_Field_Id` is called to advance to >> next field after generating initialization code for current field. Due >> to the presence of `struct string`, the field_id and fld is no long in >> sync. For example, after generating initialization code for >> ftp_info.symlink, the field_id is the for the last field of symlink >> struct (ftp_info.symlink.source) while fld still points to >> ftp_info.symlink field. This caused field_id being incremented >> incorrectly and caused segmentation fault in `FLD_get_to_field` >> function. >> >> >> Thanks. >> ------------------------------- >> Feng Zhou >> >> ------------------------------------------------------------------------------ >> Protect Your Site and Customers from Malware Attacks >> Learn about various malware tactics and how to avoid them. Understand >> malware threats, the impact they can have on your business, and how you >> can protect your company and customers by using code signing. >> http://p.sf.net/sfu/oracle-sfdevnl >> _______________________________________________ >> Open64-devel mailing list >> Open64-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/open64-devel >> >> > > > > -- > Thanks. > Handong > ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Open64-devel mailing list Open64-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/open64-devel
