From 90ed9b8bc136c80116273d1aae5a31fbd415af27 Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Thu, 15 Dec 2016 15:22:49 +0000 Subject: [PATCH] bfd/dwarf: Improve use of previously loaded dwarf information When parsing DWARF data in order to report file/line type error messages we perform section placement to make section addresses unique within relocatable object files. Currently, if we reuse previously loaded (and cached) dwarf data then we neglect to perform section placement, the result is that the section addresses will not be unique, and we might, incorrectly associate an address with the wrong debug information, and so report an incorrect file and line number. Further we neglect to check that that bfd for which we are looking up debug information is actually the bfd for which the previous debug information was loaded, it is possible that we will reuse previously loaded debug information for a different bfd. And finally, due to following of gnu_debuglink links in one bfd to another, the process of checking that the cached debug information is valid requires us to track the original bfd in the cached debug information. The original debug information here is either the bfd that we're interested in, not the bfd we finally load the debug information from. bfd/ChangeLog: * dwarf2.c (struct dwarf2_debug): Add orig_bfd member. (_bfd_dwarf2_slurp_debug_info): If stashed debug information does not match current bfd, then reload debug information. Record bfd we're loading debug info for in the stash. If we have debug informatin in the cache then perform section placement before returning. ld/ChangeLog: * testsuite/ld-elf/dwarf.exp (build_tests): Add new tests. * testsuite/ld-elf/dwarf2.err: New file. * testsuite/ld-elf/dwarf2a.c: New file. * testsuite/ld-elf/dwarf2b.c: New file. * testsuite/ld-elf/dwarf3.c: New file. * testsuite/ld-elf/dwarf3.err: New file. --- bfd/ChangeLog | 9 +++++++++ bfd/dwarf2.c | 23 +++++++++++++++++++++-- ld/ChangeLog | 9 +++++++++ ld/testsuite/ld-elf/dwarf.exp | 6 ++++++ ld/testsuite/ld-elf/dwarf2.err | 4 ++++ ld/testsuite/ld-elf/dwarf2a.c | 8 ++++++++ ld/testsuite/ld-elf/dwarf2b.c | 10 ++++++++++ ld/testsuite/ld-elf/dwarf3.c | 13 +++++++++++++ ld/testsuite/ld-elf/dwarf3.err | 4 ++++ 9 files changed, 84 insertions(+), 2 deletions(-) create mode 100644 ld/testsuite/ld-elf/dwarf2.err create mode 100644 ld/testsuite/ld-elf/dwarf2a.c create mode 100644 ld/testsuite/ld-elf/dwarf2b.c create mode 100644 ld/testsuite/ld-elf/dwarf3.c create mode 100644 ld/testsuite/ld-elf/dwarf3.err diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 0c45c44bfed..01314bda146 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,12 @@ +2017-02-16 Andrew Burgess + + * dwarf2.c (struct dwarf2_debug): Add orig_bfd member. + (_bfd_dwarf2_slurp_debug_info): If stashed debug information does + not match current bfd, then reload debug information. Record bfd + we're loading debug info for in the stash. If we have debug + informatin in the cache then perform section placement before + returning. + 2017-02-16 Alan Modra PR 21000 diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c index 6b111d3d7a0..03447a908a5 100644 --- a/bfd/dwarf2.c +++ b/bfd/dwarf2.c @@ -100,6 +100,12 @@ struct dwarf2_debug /* Pointer to the end of the .debug_info section memory buffer. */ bfd_byte *info_ptr_end; + /* Pointer to the original bfd for which debug was loaded. This is what + we use to compare and so check that the cached debug data is still + valid - it saves having to possibly dereference the gnu_debuglink each + time. */ + bfd *orig_bfd; + /* Pointer to the bfd, section and address of the beginning of the section. The bfd might be different than expected because of gnu_debuglink sections. */ @@ -3897,8 +3903,20 @@ _bfd_dwarf2_slurp_debug_info (bfd *abfd, bfd *debug_bfd, if (stash != NULL) { - if (section_vma_same (abfd, stash)) - return TRUE; + if (stash->orig_bfd == abfd + && section_vma_same (abfd, stash)) + { + /* Check that we did previously find some debug information + before attempting to make use of it. */ + if (stash->bfd_ptr != NULL) + { + if (do_place && !place_sections (abfd, stash)) + return FALSE; + return TRUE; + } + + return FALSE; + } _bfd_dwarf2_cleanup_debug_info (abfd, pinfo); memset (stash, 0, amt); } @@ -3908,6 +3926,7 @@ _bfd_dwarf2_slurp_debug_info (bfd *abfd, bfd *debug_bfd, if (! stash) return FALSE; } + stash->orig_bfd = abfd; stash->debug_sections = debug_sections; stash->syms = symbols; if (!save_section_vma (abfd, stash)) diff --git a/ld/ChangeLog b/ld/ChangeLog index 8d493737e3d..696e08afffb 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,12 @@ +2017-02-16 Andrew Burgess + + * testsuite/ld-elf/dwarf.exp (build_tests): Add new tests. + * testsuite/ld-elf/dwarf2.err: New file. + * testsuite/ld-elf/dwarf2a.c: New file. + * testsuite/ld-elf/dwarf2b.c: New file. + * testsuite/ld-elf/dwarf3.c: New file. + * testsuite/ld-elf/dwarf3.err: New file. + 2017-02-16 Andrew Burgess * testsuite/lib/ld-lib.exp (run_cc_link_tests): Add warning, diff --git a/ld/testsuite/ld-elf/dwarf.exp b/ld/testsuite/ld-elf/dwarf.exp index 529ebccd505..25b0c9d4763 100644 --- a/ld/testsuite/ld-elf/dwarf.exp +++ b/ld/testsuite/ld-elf/dwarf.exp @@ -49,6 +49,12 @@ set build_tests { {"Build libdwarf1.so" "-s -shared" "-fPIC -g -feliminate-dwarf2-dups" {dwarf1.c} {} "libdwarf1.so"} + {"DWARF parse during linker error" + "" "-fno-toplevel-reorder" + {dwarf2a.c dwarf2b.c} {{error_output "dwarf2.err"}} "dwarf2.x"} + {"Handle no DWARF information" + "" "-g0" + {dwarf3.c} {{error_output "dwarf3.err"}} "dwarf3.x"} } set run_tests { diff --git a/ld/testsuite/ld-elf/dwarf2.err b/ld/testsuite/ld-elf/dwarf2.err new file mode 100644 index 00000000000..872d2823635 --- /dev/null +++ b/ld/testsuite/ld-elf/dwarf2.err @@ -0,0 +1,4 @@ +tmpdir/dwarf2b\.o:\(\.data\+0x0\): multiple definition of `global_var' +tmpdir/dwarf2a\.o:\(\.data\+0x0\): first defined here +tmpdir/dwarf2b\.o:\(\.data\+0x4\): multiple definition of `other_var' +tmpdir/dwarf2a\.o:\(\.data\+0x4\): first defined here diff --git a/ld/testsuite/ld-elf/dwarf2a.c b/ld/testsuite/ld-elf/dwarf2a.c new file mode 100644 index 00000000000..1de5794587a --- /dev/null +++ b/ld/testsuite/ld-elf/dwarf2a.c @@ -0,0 +1,8 @@ +int global_var = 3; +int other_var = 4; + +int +function (void) +{ + return 0; +} diff --git a/ld/testsuite/ld-elf/dwarf2b.c b/ld/testsuite/ld-elf/dwarf2b.c new file mode 100644 index 00000000000..c557978f90c --- /dev/null +++ b/ld/testsuite/ld-elf/dwarf2b.c @@ -0,0 +1,10 @@ +int global_var = 4; +int other_var = 2; + +extern int function (void); + +int +main () +{ + return function (); +} diff --git a/ld/testsuite/ld-elf/dwarf3.c b/ld/testsuite/ld-elf/dwarf3.c new file mode 100644 index 00000000000..054eb9b18bc --- /dev/null +++ b/ld/testsuite/ld-elf/dwarf3.c @@ -0,0 +1,13 @@ +/* This test is actually used to test for a segfault that came from the bfd + dwarf parsing code in the case when there is _no_ dwarf info. */ + +extern void bar (int a); + +int +main () +{ + bar (1); + bar (2); + + return 0; +} diff --git a/ld/testsuite/ld-elf/dwarf3.err b/ld/testsuite/ld-elf/dwarf3.err new file mode 100644 index 00000000000..602743138c6 --- /dev/null +++ b/ld/testsuite/ld-elf/dwarf3.err @@ -0,0 +1,4 @@ +.*/dwarf3\.o: In function `main': +.*dwarf3.c:\(\.text.*\+0x[0-9a-f]+\): undefined reference to `bar' +.*dwarf3.c:\(\.text.*\+0x[0-9a-f]+\): undefined reference to `bar' +#... \ No newline at end of file -- 2.30.2