testsuite: Add support for scanning assembly with comparitor
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Commit Message
There is currently no support for matching at least x lines of assembly
(only scan-assembler-times). This patch would allow setting upper or lower
bounds.
Use case: using different scheduler descriptions and/or cost models will change
assembler output. Testing common functionality across tunes would require a
separate testcase per tune since each assembly output would be different. If we
know a base number of lines should appear across all tunes (i.e. testing return
values: we expect at minimum n stores into register x), we can lower-bound the
test to search for scan-assembler-bound {RE for storing into register x} >= n.
This avoids artificially inflating the scan-assembler-times expected count due
to the assembler choosing to perform extra stores into register x (using it as
a temporary register).
The testcase would be more robust to cpu/tune changes at the cost of not being
as granular towards specific cpu tuning.
gcc/ChangeLog:
* doc/sourcebuild.texi: add scan-assembler-bound
gcc/testsuite/ChangeLog:
* lib/scanasm.exp: add scan-assembler-bound
Signed-off-by: Edwin Lu <ewlu@rivosinc.com>
---
gcc/doc/sourcebuild.texi | 4 +++
gcc/testsuite/lib/scanasm.exp | 64 +++++++++++++++++++++++++++++++++++
2 files changed, 68 insertions(+)
Comments
On Feb 12, 2024, at 11:38 AM, Edwin Lu <ewlu@rivosinc.com> wrote:
>
> There is currently no support for matching at least x lines of assembly
> (only scan-assembler-times). This patch would allow setting upper or lower
> bounds.
>
> Use case: using different scheduler descriptions and/or cost models will change
> assembler output. Testing common functionality across tunes would require a
> separate testcase per tune since each assembly output would be different. If we
> know a base number of lines should appear across all tunes (i.e. testing return
> values: we expect at minimum n stores into register x), we can lower-bound the
> test to search for scan-assembler-bound {RE for storing into register x} >= n.
> This avoids artificially inflating the scan-assembler-times expected count due
> to the assembler choosing to perform extra stores into register x (using it as
> a temporary register).
>
> The testcase would be more robust to cpu/tune changes at the cost of not being
> as granular towards specific cpu tuning.
I didn't see an Ok? Just in case you forgot, yes, this is ok.
Thanks! Committed
Edwin
On 2/15/2024 9:27 AM, Mike Stump wrote:
> On Feb 12, 2024, at 11:38 AM, Edwin Lu <ewlu@rivosinc.com> wrote:
>> There is currently no support for matching at least x lines of assembly
>> (only scan-assembler-times). This patch would allow setting upper or lower
>> bounds.
>>
>> Use case: using different scheduler descriptions and/or cost models will change
>> assembler output. Testing common functionality across tunes would require a
>> separate testcase per tune since each assembly output would be different. If we
>> know a base number of lines should appear across all tunes (i.e. testing return
>> values: we expect at minimum n stores into register x), we can lower-bound the
>> test to search for scan-assembler-bound {RE for storing into register x} >= n.
>> This avoids artificially inflating the scan-assembler-times expected count due
>> to the assembler choosing to perform extra stores into register x (using it as
>> a temporary register).
>>
>> The testcase would be more robust to cpu/tune changes at the cost of not being
>> as granular towards specific cpu tuning.
> I didn't see an Ok? Just in case you forgot, yes, this is ok.
@@ -3396,6 +3396,10 @@ excluding LTO sections.
Passes if @var{regex} is matched exactly @var{num} times in the test's
assembler output, excluding LTO sections.
+@item scan-assembler-bound @var{regex} @var{cmp} @var{num} [@{ target/xfail @var{selector} @}]
+Passes if @var{regex} is matched @var{cmp} @var{num} times in the test's
+assembler output, excluding LTO sections. @var{cmp} is a comparitor.
+
@item scan-assembler-dem @var{regex} [@{ target/xfail @var{selector} @}]
Passes if @var{regex} matches text in the test's demangled assembler output,
excluding LTO sections.
@@ -516,6 +516,70 @@ proc scan-assembler-times { args } {
set_required_options_for scan-assembler-times
+# Call pass if pattern is present within a lower or upper bound,
+# otherwise fail.
+# ex /* { dg-final { scan-assembler-bound {RE} > 3 } }
+proc scan-assembler-bound { args } {
+ if { [llength $args] < 3 } {
+ error "scan-assembler-bound: too few arguments"
+ return
+ }
+ if { [llength $args] > 4 } {
+ error "scan-assembler-bound: too many arguments"
+ return
+ }
+ if { [llength $args] >= 4 } {
+ switch [dg-process-target [lindex $args 3]] {
+ "S" { }
+ "N" { return }
+ "F" { setup_xfail "*-*-*" }
+ "P" { }
+ }
+ }
+
+ set testcase [testname-for-summary]
+ # The name might include a list of options; extract the file name.
+ set filename [lindex $testcase 0]
+ set pattern [lindex $args 0]
+ set cmp [lindex $args 1]
+ set bound [lindex $args 2]
+ set pp_pattern [make_pattern_printable $pattern]
+
+ # This must match the rule in gcc-dg.exp.
+ set output_file "[file rootname [file tail $filename]].s"
+
+ set files [glob -nocomplain $output_file]
+ if { $files == "" } {
+ verbose -log "$testcase: output file does not exist"
+ unresolved "$testcase scan-assembler-bound $pp_pattern $min $max"
+ return
+ }
+
+ if { [lsearch { < > <= >= } $cmp] == -1 } {
+ error "scan-assembler-bound: illegal argument: $cmp"
+ return
+ }
+ if ![string is integer $bound ] {
+ error "scan-assembler-bound: illegal argument: $bound"
+ return
+ }
+
+ set fd [open $output_file r]
+ set text [read $fd]
+ 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 [regexp -all -- $pattern $text]
+ if [expr $result_count $cmp $bound] {
+ pass "$testcase scan-assembler-bound $pp_pattern $cmp $bound"
+ } else {
+ verbose -log "$testcase: $pp_pattern found $result_count times"
+ fail "$testcase scan-assembler-bound $pp_pattern $cmp $bound"
+ }
+}
+
+set_required_options_for scan-assembler-bound
+
# Utility for scanning demangled compiler result, invoked via dg-final.
# Call pass if pattern is present, otherwise fail.
proc scan-assembler-dem { args } {