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Fix gdb.base/align-*.exp and Clang + LTO and AIX GCC

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Clang with LTO (clang -flto) garbage collects unused global variables,
Thus, gdb.base/align-c.exp and gdb.base/align-c++.exp fail with
hundreds of FAILs like so:

 $ make check \
    TESTS="gdb.*/align-*.exp" \
    RUNTESTFLAGS="CC_FOR_TARGET='clang -flto' CXX_FOR_TARGET='clang++ -flto'"
 ...
 FAIL: gdb.base/align-c.exp: get integer valueof "a_char"
 FAIL: gdb.base/align-c.exp: print _Alignof(char)
 FAIL: gdb.base/align-c.exp: get integer valueof "a_char_x_char"
 FAIL: gdb.base/align-c.exp: print _Alignof(struct align_pair_char_x_char)
 FAIL: gdb.base/align-c.exp: get integer valueof "a_char_x_unsigned_char"
 ...

AIX GCC has the same issue, and there the easier way of adding
__attribute__((used)) to globals does not help.

So add explicit uses of all globals to the generated code.

For the C++ test, that reveals that the static variable members of the
generated structs are not defined anywhere, leading to undefined
references.  Fixed by emitting initialization for all static members.

Lastly, I noticed that CXX_FOR_TARGET was being ignored -- that's
because the align-c++.exp testcase is compiling with the C compiler
driver.  Fixed by passing "c++" as option to prepare_for_testing.

Change-Id: I874b717afde7b6fb1e45e526912b518a20a12716
This commit is contained in:
Pedro Alves 2023-03-29 13:21:20 +01:00
parent a52aeef923
commit b4f767131f
1 changed files with 47 additions and 2 deletions
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49
gdb/testsuite/gdb.base/align.exp.tcl
View file

@ -94,12 +94,15 @@ proc prepare_test_source_file { lang } {
puts $outfile "DEF_WITH_1_STATIC ($utype, $uinner);"
set joined "static_${utype}_x_${uinner}"
puts $outfile "struct align_pair_$joined item_${joined};"
puts $outfile "$utype align_pair_${joined}::one = 0;"
puts $outfile "unsigned a_${joined}"
puts $outfile " = ${align_func} (struct align_pair_${joined});"
puts $outfile "DEF_WITH_2_STATIC ($utype, $uinner);"
set joined "static_${utype}_x_static_${uinner}"
puts $outfile "struct align_pair_$joined item_${joined};"
puts $outfile "$utype align_pair_${joined}::one = 0;"
puts $outfile "$uinner align_pair_${joined}::two = 0;"
puts $outfile "unsigned a_${joined}"
puts $outfile " = ${align_func} (struct align_pair_${joined});"
}
@ -107,12 +110,53 @@ proc prepare_test_source_file { lang } {
}
# Epilogue.
puts $outfile {
puts $outfile "
int main() {
return 0;
"
# Clang with LTO garbage collects unused global variables, even at
# -O0. Likewise AIX GCC. Add uses to all global variables to
# prevent it.
if { $lang == "c" } {
puts $outfile "a_void++;"
}
# First, add uses for single items.
foreach type $typelist {
set utype [join [split $type] _]
puts $outfile "item_$utype++;"
if { $lang == "c" } {
puts $outfile "a_$utype++;"
}
}
# Now add uses for all pairs.
foreach type $typelist {
set utype [join [split $type] _]
foreach inner $typelist {
set uinner [join [split $inner] _]
set joined "${utype}_x_${uinner}"
puts $outfile "item_${joined}.one++;"
puts $outfile "a_${joined}++;"
if { $lang == "c++" } {
set joined "static_${utype}_x_${uinner}"
puts $outfile "item_${joined}.one++;"
puts $outfile "a_${joined}++;"
set joined "static_${utype}_x_static_${uinner}"
puts $outfile "item_${joined}.one++;"
puts $outfile "a_${joined}++;"
}
}
}
puts $outfile "
return 0;
}
"
close $outfile
return $filename
@ -127,6 +171,7 @@ proc run_alignment_test { lang } {
set flags {debug}
if { "$lang" == "c++" } {
lappend flags "c++"
lappend flags "additional_flags=-std=c++11"
}
standard_testfile $filename