| Message ID | alpine.DEB.2.20.2311190446360.5892@tpp.orcam.me.uk |
|---|---|
| State | New |
| Headers | show |
| Series | testsuite: Fix subexpressions with `scan-assembler-times' | expand |
On 11/19/23 04:27, Maciej W. Rozycki wrote: > We have an issue with `scan-assembler-times' handling expressions using > subexpressions as produced by capturing parentheses `()' in an odd way, > and one that is inconsistent with `scan-assembler', `scan-assembler-not', > etc. The problem comes from calling `regexp' with `-inline -all', which > causes a list to be returned that would otherwise be placed in match > variables. > > Consequently if we have say: > > /* { dg-final { scan-assembler-times "\\s(foo|bar)\\s" 1 } } */ > > in a test case and there is a lone `foo' present in output being matched, > then our invocation of `regexp -inline -all' in `scan-assembler-times' > will return: > > { foo } foo > > and that in turn will confuse our match count calculation as `llength' > will return 2 rather than 1, making the test fail even though `foo' was > only actually matched once. > > It seems unclear why we chose to call `regexp' in such an odd way in the > first place just to figure out the number of matches. The first version > of TCL that supports the `-all' option to `regexp' is 8.3, and according > to its documentation[1][2] `regexp' already returns the number of matches > found whenever `-all' has been used *unless* `-inline' has also been used. > > Remove the `-inline' option then along with the `llength' invocation. > > References: > > [1] "Tcl Built-In Commands - regexp manual page", > <https://www.tcl.tk/man/tcl8.2.3/TclCmd/regexp.html> > > [2] "Tcl Built-In Commands - regexp manual page", > <https://www.tcl.tk/man/tcl8.3/TclCmd/regexp.html> > > gcc/testsuite/ > * lib/scanasm.exp (scan-assembler-times): Remove the `-inline' > option to `regexp' and the wrapping `llength' call. > --- > Hi, > > Verified with the `riscv64-linux-gnu' target and the C language > testsuite. OK to apply? Not sure why it is the way it is -- I walked back to Zdenek's change which introduced the scan-assembler-times and nothing about the -inline argument. OK, but be on the lookout for scan-asm problems on other targets over the next few days. Jeff
On Sun, 19 Nov 2023, Jeff Law wrote: > > Verified with the `riscv64-linux-gnu' target and the C language > > testsuite. OK to apply? > Not sure why it is the way it is -- I walked back to Zdenek's change which > introduced the scan-assembler-times and nothing about the -inline argument. I went through our history beforehand too and found nothing interesting either. My only suspicion has been it may have happened as a conseqence of somewhat confusing regexp(n) TCL documentation just saying: "Determines whether the regular expression exp matches part or all of string and returns 1 if it does, 0 if it does not, unless -inline is specified (see below)." and then you need to dive into the description of `-all' to find out it actually returns the number of matches rather than just 1 or 0: "Causes the regular expression to be matched as many times as possible in the string, returning the total number of matches found." I guess maybe Zdenek missed the part after the comma? > OK, but be on the lookout for scan-asm problems on other targets over the next > few days. Good point. I have grepped our testsuite for instances and found only one (as opposed to numerous non-captured subexpressions), specifically gcc/testsuite/gcc.target/arm/pr53447-5.c, well-documented as working around the quirk. I've posted a change to avoid the quirk with this case: <https://gcc.gnu.org/pipermail/gcc-patches/2023-November/637710.html> and I mean to apply it just before this `scan-assembler-times' fix. Maciej
Index: gcc/gcc/testsuite/lib/scanasm.exp =================================================================== --- gcc.orig/gcc/testsuite/lib/scanasm.exp +++ gcc/gcc/testsuite/lib/scanasm.exp @@ -505,7 +505,7 @@ proc scan-assembler-times { args } { close $fd regsub -all {(^|\n)[[:space:]]*\.section[[:space:]]*\.gnu\.lto_(?:[^\n]*\n(?![[:space:]]*\.(section|text|data|bss)))*[^\n]*\n} $text {\1} text - set result_count [llength [regexp -inline -all -- $pattern $text]] + set result_count [regexp -all -- $pattern $text] if {$result_count == $times} { pass "$testcase scan-assembler-times $pp_pattern $times" } else {
We have an issue with `scan-assembler-times' handling expressions using subexpressions as produced by capturing parentheses `()' in an odd way, and one that is inconsistent with `scan-assembler', `scan-assembler-not', etc. The problem comes from calling `regexp' with `-inline -all', which causes a list to be returned that would otherwise be placed in match variables. Consequently if we have say: /* { dg-final { scan-assembler-times "\\s(foo|bar)\\s" 1 } } */ in a test case and there is a lone `foo' present in output being matched, then our invocation of `regexp -inline -all' in `scan-assembler-times' will return: { foo } foo and that in turn will confuse our match count calculation as `llength' will return 2 rather than 1, making the test fail even though `foo' was only actually matched once. It seems unclear why we chose to call `regexp' in such an odd way in the first place just to figure out the number of matches. The first version of TCL that supports the `-all' option to `regexp' is 8.3, and according to its documentation[1][2] `regexp' already returns the number of matches found whenever `-all' has been used *unless* `-inline' has also been used. Remove the `-inline' option then along with the `llength' invocation. References: [1] "Tcl Built-In Commands - regexp manual page", <https://www.tcl.tk/man/tcl8.2.3/TclCmd/regexp.html> [2] "Tcl Built-In Commands - regexp manual page", <https://www.tcl.tk/man/tcl8.3/TclCmd/regexp.html> gcc/testsuite/ * lib/scanasm.exp (scan-assembler-times): Remove the `-inline' option to `regexp' and the wrapping `llength' call. --- Hi, Verified with the `riscv64-linux-gnu' target and the C language testsuite. OK to apply? Maciej --- gcc/testsuite/lib/scanasm.exp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) gcc-test-scan-assembler-times-count.diff