141 lines
6.5 KiB
Diff
141 lines
6.5 KiB
Diff
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Fix for gdb.base/solib-search.exp test.
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The variable right_lib_flags is not being set correctly to define RIGHT.
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The value RIGHT is needed to force the address of the library functions
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lib1_func3 and lib2_func4 to occur at different address in the wrong and
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right libraries.
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With RIGHT defined correctly, functions lib1_func3 and lib2_func4 occur
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at different addresses the test runs correctly on Powerpc.
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The test needs the lib2 addresses to be different in the right and
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wrong cases. That is the point of introducing function lib2_spacer
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with the ifdef RIGHT compiler directive.
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On Intel, the ARRAY_SIZE of 1 versus 8192 is sufficient to get the
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dynamic linker to move the addresses of the library. You can also get
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the same effect on PowerPC but you must use a value much larger than
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8192.
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The key thing is that the test was not properly setting RIGHT to
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defined to get the lib2_spacer function on Intel and Powerpc.
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Without the patch, we have the Intel backtrace for the bad libraries:
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backtrace
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#0 break_here () at /home/ ... /gdb/testsuite/gdb.base/solib-search.c:30
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#1 0x00007ffff7fae156 in ?? ()
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#2 0x00007fffffffc150 in ?? ()
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#3 0x00007ffff7fbb156 in ?? ()
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#4 0x00007fffffffc160 in ?? ()
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#5 0x00007ffff7fae146 in ?? ()
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#6 0x00007fffffffc170 in ?? ()
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#7 0x00007ffff7fbb146 in ?? ()
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#8 0x00007fffffffc180 in ?? ()
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#9 0x0000555555555156 in main () at /home/ ... /binutils-gdb/gdb/testsuite/gdb.base/solib-search.c:23
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Backtrace stopped: previous frame inner to this frame (corrupt stack?)
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(gdb) PASS: gdb.base/solib-search.exp: backtrace (with wrong libs) (data collection)
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The backtrace on Intel with the good libraries is:
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backtrace
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#0 break_here () at /.../binutils-gdb/gdb/testsuite/gdb.base/solib-search.c:30
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#1 0x00007ffff7fae156 in lib2_func4 () at /.../binutils-gdb/gdb/testsuite/gdb.base/solib-search-lib2.c:49
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#2 0x00007ffff7fbb156 in lib1_func3 () at /.../gdb.base/solib-search-lib1.c:49
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#3 0x00007ffff7fae146 in lib2_func2 () at /.../testsuite/gdb.base/solib-search-lib2.c:30
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#4 0x00007ffff7fbb146 in lib1_func1 () at /.../gdb.base/solib-search-lib1.c:30
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#5 0x0000555555555156 in main () at /...solib-search.c:23
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(gdb) PASS: gdb.base/solib-search.exp: backtrace (with right libs) (data collection)
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PASS: gdb.base/solib-search.exp: backtrace (with right libs)
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In one case the backtrace is correct and the other it
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is wrong on Intel. This is due to the fact that the ARRAY_SIZE caused
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the dynamic linker to move the library function addresses around. I
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believe it has to do with the default size of the data and code
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sections used by the dynamic linker.
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So without the patch the backtrace on PowerPC looks like:
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backtrace
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#0 break_here () at /.../solib-search.c:30
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#1 0x00007ffff7f007f4 in lib2_func4 () at /.../solib-search-lib2.c:49
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#2 0x00007ffff7f307f4 in lib1_func3 () at /.../solib-search-lib1.c:49
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#3 0x00007ffff7f007ac in lib2_func2 () at /.../solib-search-lib2.c:30
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#4 0x00007ffff7f307ac in lib1_func1 () at /.../solib-search-lib1.c:30
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#5 0x000000001000074c in main () at /.../solib-search.c:23
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for both the good and bad libraries.
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The patch fixes defining RIGHT in solib-search-lib1.c and solib-search-
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lib2.c. Note, without the patch the lib1_spacer and lib2_spacer
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functions do not show up in the object dump of the Intel or Powerpc
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libraries as it should. The patch fixes that by making sure RIGHT gets
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defined.
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Now with the patch the backtrace for the bad library on PowerPC looks
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like:
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backtrace
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#0 break_here () at /.../solib-search.c:30
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#1 0x00007ffff7f0083c in __glink_PLTresolve () from /.../solib-search-lib2.so
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Backtrace stopped: frame did not save the PC
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And the backtrace for the good libraries on PowerPC looks like:
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backtrace
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#0 break_here () at /.../solib-search.c:30
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#1 0x00007ffff7f0083c in lib2_func4 () at /.../solib-search-lib2.c:49
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#2 0x00007ffff7f3083c in lib1_func3 () at /.../solib-search-lib1.c:49
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#3 0x00007ffff7f007cc in lib2_func2 () at /.../solib-search-lib2.c:30
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#4 0x00007ffff7f307cc in lib1_func1 () at /.../solib-search-lib1.c:30
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#5 0x000000001000074c in main () at /.../solib-search.c:23
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(gdb) PASS: gdb.base/solib-search.exp: backtrace (with right libs) (data collection)
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PASS: gdb.base/solib-search.exp: backtrace (with right libs)
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The issue then is on Power where the ARRAY_SIZE of 1 versus 8192 is not
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sufficient to cause the dymanic linker to allocate the libraries at
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different addresses. I don't claim to understand the specifics of how
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the dynamic linker works and what the default size is for the data and
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code sections are. My guess is by default PowerPC allocates a larger
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data size by default, which is large enough to hold array[8192]. The
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default size of the data section allocated by the dynamic linker on
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Intel is not large enough to hold array[8192] thus causing the code
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section on Intel to have to move when the large array is defined.
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Note on PowerPC, if you make ARRAY_SIZE big enough, then you will cause
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the library addresses to occur at different addresses as the larger
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data section forces the code section to a different address. That was
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actually my original fix for the program until I spoke with Doug Evans
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who originally wrote the test. Doug noticed that RIGHT was not getting
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defined as he originally intended in the test.
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With the patch to fix the definition of RIGHT, PowerPC has a bad and a
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good backtrace because the address of lib1_func3 and lib2_func4 both
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move because lib1_spacer and lib2_spacer are now defined
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before lib1_func3 and lib2_func4.
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Without the patch, the lib1_spacer and lib2_spacer function doesn't show
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up in the binary for the correct or incorrect library on Intel or PowerPC.
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With the patch, RIGHT gets defined as originally intended for the test on
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both architectures and lib1_spacer and lib2_spacer function show up in the
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binaries on both architectures changing the other function addresses as
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intended thus causing the test work as intended on PowerPC.
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---
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gdb/testsuite/gdb.base/solib-search.exp | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/gdb/testsuite/gdb.base/solib-search.exp b/gdb/testsuite/gdb.base/solib-search.exp
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index eaabe508bf0..202e79d85de 100644
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--- a/gdb/testsuite/gdb.base/solib-search.exp
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+++ b/gdb/testsuite/gdb.base/solib-search.exp
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@@ -54,7 +54,7 @@ set binfile2_lib [standard_output_file ${libname2}.so]
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set lib_flags [list debug ldflags=-Wl,-Bsymbolic]
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set wrong_lib_flags "$lib_flags additional_flags=-DARRAY_SIZE=1"
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-set right_lib_flags "$lib_flags additional_flags=-DARRAY_SIZE=8192 -DRIGHT"
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+set right_lib_flags "$lib_flags additional_flags=-DARRAY_SIZE=8192 additional_flags=-DRIGHT"
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# Binary file.
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standard_testfile .c
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