From 382df1c6744d09e9f3362f9743788574913980b4 Mon Sep 17 00:00:00 2001 From: Mitch Phillips <31459023+hctim@users.noreply.github.com> Date: Fri, 7 Aug 2020 10:56:33 -0700 Subject: [PATCH] Revert "Reland D64327 [MC][ELF] Allow STT_SECTION referencing SHF_MERGE on REL targets" This reverts commit b497665d98ad5026b1d3d67d5793a28fefe27bea. Spent some time trying to reproduce this locally, reverting in a desparate attempt to fix the sanitizer buildbot: - http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/28828 I don't know exactly why or how this patch breaks the bots, but it seems pretty concrete that it's the culprit. --- llvm/cmake/modules/AddLLVM.cmake | 9 ++------- llvm/lib/MC/ELFObjectWriter.cpp | 5 +++++ llvm/test/MC/ELF/basic-elf-32.s | 4 ++-- llvm/test/MC/ELF/compression.s | 4 ++-- llvm/test/MC/ELF/relocation-386.s | 2 +- llvm/test/MC/Mips/elf-relsym.s | 10 ++++++++-- llvm/test/MC/Mips/xgot.s | 4 ++-- 7 files changed, 22 insertions(+), 16 deletions(-) diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake index 2ff5c29..ac3d5c8 100644 --- a/llvm/cmake/modules/AddLLVM.cmake +++ b/llvm/cmake/modules/AddLLVM.cmake @@ -222,13 +222,8 @@ function(add_link_opts target_name) # Pass -O3 to the linker. This enabled different optimizations on different # linkers. if(NOT (${CMAKE_SYSTEM_NAME} MATCHES "Darwin|SunOS|AIX" OR WIN32)) - # Before binutils 2.34, gold -O2 and above did not correctly handle R_386_GOTOFF to - # SHF_MERGE|SHF_STRINGS sections: https://sourceware.org/bugzilla/show_bug.cgi?id=16794 - if(LLVM_LINKER_IS_GOLD) - set_property(TARGET ${target_name} APPEND_STRING PROPERTY LINK_FLAGS " -Wl,-O1") - else() - set_property(TARGET ${target_name} APPEND_STRING PROPERTY LINK_FLAGS " -Wl,-O3") - endif() + set_property(TARGET ${target_name} APPEND_STRING PROPERTY + LINK_FLAGS " -Wl,-O3") endif() if(LLVM_LINKER_IS_GOLD) diff --git a/llvm/lib/MC/ELFObjectWriter.cpp b/llvm/lib/MC/ELFObjectWriter.cpp index b44a36b..494f825 100644 --- a/llvm/lib/MC/ELFObjectWriter.cpp +++ b/llvm/lib/MC/ELFObjectWriter.cpp @@ -1393,6 +1393,11 @@ bool ELFObjectWriter::shouldRelocateWithSymbol(const MCAssembler &Asm, if (Flags & ELF::SHF_MERGE) { if (C != 0) return true; + + // It looks like gold has a bug (http://sourceware.org/PR16794) and can + // only handle section relocations to mergeable sections if using RELA. + if (!hasRelocationAddend()) + return true; } // Most TLS relocations use a got, so they need the symbol. Even those that diff --git a/llvm/test/MC/ELF/basic-elf-32.s b/llvm/test/MC/ELF/basic-elf-32.s index 1a92310..effc363 100644 --- a/llvm/test/MC/ELF/basic-elf-32.s +++ b/llvm/test/MC/ELF/basic-elf-32.s @@ -46,9 +46,9 @@ main: # @main // CHECK: Relocations [ // CHECK: Section {{.*}} .rel.text { -// CHECK: 0x6 R_386_32 .rodata.str1.1 0x0 +// CHECK: 0x6 R_386_32 .L.str1 // CHECK: 0xB R_386_PC32 puts -// CHECK: 0x12 R_386_32 .rodata.str1.1 0x0 +// CHECK: 0x12 R_386_32 .L.str2 // CHECK: 0x17 R_386_PC32 puts // CHECK: } // CHECK: ] diff --git a/llvm/test/MC/ELF/compression.s b/llvm/test/MC/ELF/compression.s index 9bc5c0e..93a77b3 100644 --- a/llvm/test/MC/ELF/compression.s +++ b/llvm/test/MC/ELF/compression.s @@ -38,7 +38,7 @@ // In x86 32 bit named symbols are used for temporary symbols in merge // sections, so make sure we handle symbols inside compressed sections -// 386-SYMBOLS-GNU: Name: .zdebug_str +// 386-SYMBOLS-GNU: Name: .Linfo_string0 // 386-SYMBOLS-GNU-NOT: } // 386-SYMBOLS-GNU: Section: .zdebug_str @@ -73,7 +73,7 @@ // ZLIB-STYLE-FLAGS32-NEXT: AddressAlignment: 4 // ZLIB-STYLE-FLAGS64-NEXT: AddressAlignment: 8 -// 386-SYMBOLS-ZLIB: Name: .debug_str +// 386-SYMBOLS-ZLIB: Name: .Linfo_string0 // 386-SYMBOLS-ZLIB-NOT: } // 386-SYMBOLS-ZLIB: Section: .debug_str diff --git a/llvm/test/MC/ELF/relocation-386.s b/llvm/test/MC/ELF/relocation-386.s index b9bf9b6..4273750 100644 --- a/llvm/test/MC/ELF/relocation-386.s +++ b/llvm/test/MC/ELF/relocation-386.s @@ -8,7 +8,7 @@ // I386: Format: elf32-i386 // CHECK: Relocations [ // CHECK-NEXT: Section {{.*}} .rel.text { -// CHECK-NEXT: 0x2 R_386_GOTOFF .rodata.str1.16 0x0 +// CHECK-NEXT: 0x2 R_386_GOTOFF .Lfoo 0x0 // CHECK-NEXT: 0x{{[^ ]+}} R_386_PLT32 bar2 0x0 // CHECK-NEXT: 0x{{[^ ]+}} R_386_GOTPC _GLOBAL_OFFSET_TABLE_ 0x0 // Relocation 3 (bar3@GOTOFF) is done with symbol 7 (bss) diff --git a/llvm/test/MC/Mips/elf-relsym.s b/llvm/test/MC/Mips/elf-relsym.s index d19b4e3..b8c2f89 100644 --- a/llvm/test/MC/Mips/elf-relsym.s +++ b/llvm/test/MC/Mips/elf-relsym.s @@ -4,10 +4,16 @@ // CHECK: Symbols [ // CHECK: Symbol { -// CHECK: Name: .rodata.cst8 +// CHECK: Name: $.str // CHECK: } // CHECK: Symbol { -// CHECK: Name: .rodata.str1.1 +// CHECK: Name: $.str1 +// CHECK: } +// CHECK: Symbol { +// CHECK: Name: $CPI0_0 +// CHECK: } +// CHECK: Symbol { +// CHECK: Name: $CPI0_1 // CHECK: } // CHECK: ] diff --git a/llvm/test/MC/Mips/xgot.s b/llvm/test/MC/Mips/xgot.s index 76490f0..100d25e 100644 --- a/llvm/test/MC/Mips/xgot.s +++ b/llvm/test/MC/Mips/xgot.s @@ -10,8 +10,8 @@ // CHECK: 0x1C R_MIPS_GOT_LO16 ext_1 // CHECK: 0x24 R_MIPS_CALL_HI16 printf // CHECK: 0x30 R_MIPS_CALL_LO16 printf -// CHECK: 0x2C R_MIPS_GOT16 .rodata.str1.1 0x0 -// CHECK: 0x38 R_MIPS_LO16 .rodata.str1.1 0x0 +// CHECK: 0x2C R_MIPS_GOT16 $.str +// CHECK: 0x38 R_MIPS_LO16 $.str // CHECK: ] .text -- 2.7.4