From 2ea53e003163338a403d5afbb2046cafb8f3abe9 Mon Sep 17 00:00:00 2001 From: Nick Clifton Date: Tue, 9 Feb 2016 09:56:21 +0000 Subject: [PATCH] Add a more helpful warning message to explain why some AArch64 relocations can overflow. bfd * elfnn-aarch64.c (elfNN_aarch64_relocate_section): Add a more helpful warning message to explain why certain AArch64 relocs might overflow. ld * testsuite/ld-aarch64/reloc-overflow-bad.d: New test. * testsuite/ld-aarch64/reloc-overflow-1.s: New source file. * testsuite/ld-aarch64/reloc-overflow-2.s: New source file. * testsuite/ld-aarch64/aarch64-elf.exp: Run the new test. --- bfd/ChangeLog | 6 ++++ bfd/elfnn-aarch64.c | 35 +++++++++++++++++--- ld/ChangeLog | 7 ++++ ld/testsuite/ld-aarch64/aarch64-elf.exp | 6 ++-- ld/testsuite/ld-aarch64/reloc-overflow-1.s | 14 ++++++++ ld/testsuite/ld-aarch64/reloc-overflow-2.s | 5 +++ ld/testsuite/ld-aarch64/reloc-overflow-bad.d | 4 +++ 7 files changed, 71 insertions(+), 6 deletions(-) create mode 100644 ld/testsuite/ld-aarch64/reloc-overflow-1.s create mode 100644 ld/testsuite/ld-aarch64/reloc-overflow-2.s create mode 100644 ld/testsuite/ld-aarch64/reloc-overflow-bad.d diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 88c663c19a3..3c2e8cbdba6 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,9 @@ +2016-02-09 Nick Clifton + + * elfnn-aarch64.c (elfNN_aarch64_relocate_section): Add a more + helpful warning message to explain why certain AArch64 relocs + might overflow. + 2016-02-05 Simon Marchi * pe-mips.c (coff_mips_reloc): Fix formatting. diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c index 292470df73e..99acab4e7d0 100644 --- a/bfd/elfnn-aarch64.c +++ b/bfd/elfnn-aarch64.c @@ -6405,10 +6405,6 @@ elfNN_aarch64_relocate_section (bfd *output_bfd, break; } - if (!save_addend) - addend = 0; - - /* Dynamic relocs are not propagated for SEC_DEBUGGING sections because such sections are not SEC_ALLOC and thus ld.so will not process them. */ @@ -6448,6 +6444,34 @@ elfNN_aarch64_relocate_section (bfd *output_bfd, name, input_bfd, input_section, rel->r_offset); return FALSE; } + /* Overflow can occur when a variable is referenced with a type + that has a larger alignment than the type with which it was + declared. eg: + file1.c: extern int foo; int a (void) { return foo; } + file2.c: char bar, foo, baz; + If the variable is placed into a data section at an offset + that is incompatible with the larger alignment requirement + overflow will occur. (Strictly speaking this is not overflow + but rather an alignment problem, but the bfd_reloc_ error + enum does not have a value to cover that situation). + + Try to catch this situation here and provide a more helpful + error message to the user. */ + if (addend & ((1 << howto->rightshift) - 1) + /* FIXME: Are we testing all of the appropriate reloc + types here ? */ + && (real_r_type == BFD_RELOC_AARCH64_LD_LO19_PCREL + || real_r_type == BFD_RELOC_AARCH64_LDST16_LO12 + || real_r_type == BFD_RELOC_AARCH64_LDST32_LO12 + || real_r_type == BFD_RELOC_AARCH64_LDST64_LO12 + || real_r_type == BFD_RELOC_AARCH64_LDST128_LO12)) + { + info->callbacks->warning + (info, _("One possible cause of this error is that the \ +symbol is being referenced in the indicated code as if it had a larger \ +alignment than was declared where it was defined."), + name, input_bfd, input_section, rel->r_offset); + } break; case bfd_reloc_undefined: @@ -6482,6 +6506,9 @@ elfNN_aarch64_relocate_section (bfd *output_bfd, break; } } + + if (!save_addend) + addend = 0; } return TRUE; diff --git a/ld/ChangeLog b/ld/ChangeLog index 584a8dd09d9..fb4d31f5356 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -1,3 +1,10 @@ +2016-02-09 Nick Clifton + + * testsuite/ld-aarch64/reloc-overflow-bad.d: New test. + * testsuite/ld-aarch64/reloc-overflow-1.s: New source file. + * testsuite/ld-aarch64/reloc-overflow-2.s: New source file. + * testsuite/ld-aarch64/aarch64-elf.exp: Run the new test. + 2016-02-04 Nick Clifton * testsuite/ld-arm/arm-elf.exp: Remove ARM NOREAD section tests. diff --git a/ld/testsuite/ld-aarch64/aarch64-elf.exp b/ld/testsuite/ld-aarch64/aarch64-elf.exp index 939539ec809..d0b33cf5a46 100644 --- a/ld/testsuite/ld-aarch64/aarch64-elf.exp +++ b/ld/testsuite/ld-aarch64/aarch64-elf.exp @@ -159,6 +159,8 @@ run_dump_test "emit-relocs-537" run_dump_test "emit-relocs-537-overflow" run_dump_test "emit-relocs-538" +run_dump_test "reloc-overflow-bad" + # test addend correctness when --emit-relocs specified for non-relocatable obj. run_dump_test "emit-relocs-local-addend" # test addend correctness when -r specified. @@ -281,9 +283,9 @@ run_dump_test "plt_mapping_symbol" set aarch64elflinktests { {"ld-aarch64/so with global symbol" "-shared" "" "" {copy-reloc-so.s} - {} "copy-reloc-so.so"} + {} "copy-reloc-so.so"} {"ld-aarch64/exe with copy relocation" "-e0 tmpdir/copy-reloc-so.so" "" "" - {copy-reloc-exe.s} {{objdump -R copy-reloc.d}} "copy-reloc"} + {copy-reloc-exe.s} {{objdump -R copy-reloc.d}} "copy-reloc"} } run_ld_link_tests $aarch64elflinktests diff --git a/ld/testsuite/ld-aarch64/reloc-overflow-1.s b/ld/testsuite/ld-aarch64/reloc-overflow-1.s new file mode 100644 index 00000000000..9f85fd8869a --- /dev/null +++ b/ld/testsuite/ld-aarch64/reloc-overflow-1.s @@ -0,0 +1,14 @@ + .file "1.c" + .text + .align 2 + .p2align 3,,7 + .global dec + .arch armv8-a+fp+simd + //.tune generic + .type dec, %function +dec: + adrp x0, var_2 + ldr w0, [x0, #:lo12:var_2] + ret + .size dec, .-dec + .ident "GCC: (GNU) 6.0.0 20160208 (experimental) [trunk revision 233206]" diff --git a/ld/testsuite/ld-aarch64/reloc-overflow-2.s b/ld/testsuite/ld-aarch64/reloc-overflow-2.s new file mode 100644 index 00000000000..4956f016eb2 --- /dev/null +++ b/ld/testsuite/ld-aarch64/reloc-overflow-2.s @@ -0,0 +1,5 @@ + .file "2.c" + .comm var_3,1,1 + .comm var_2,1,1 + .comm var_1,1,1 + .ident "GCC: (GNU) 6.0.0 20160208 (experimental) [trunk revision 233206]" diff --git a/ld/testsuite/ld-aarch64/reloc-overflow-bad.d b/ld/testsuite/ld-aarch64/reloc-overflow-bad.d new file mode 100644 index 00000000000..39f7e31f535 --- /dev/null +++ b/ld/testsuite/ld-aarch64/reloc-overflow-bad.d @@ -0,0 +1,4 @@ +#source: reloc-overflow-1.s +#source: reloc-overflow-2.s +#ld: -e0 +#error: .*One possible cause.* -- 2.30.2