diff options
Diffstat (limited to 'lld')
| -rw-r--r-- | lld/ELF/Config.h | 1 | ||||
| -rw-r--r-- | lld/ELF/Driver.cpp | 2 | ||||
| -rw-r--r-- | lld/ELF/Writer.cpp | 15 | ||||
| -rw-r--r-- | lld/test/ELF/keep-data-section-prefix.s | 89 |
4 files changed, 106 insertions, 1 deletions
diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h index d9639b0..e7622dd 100644 --- a/lld/ELF/Config.h +++ b/lld/ELF/Config.h @@ -404,6 +404,7 @@ struct Config { bool zIfuncNoplt; bool zInitfirst; bool zInterpose; + bool zKeepDataSectionPrefix; bool zKeepTextSectionPrefix; bool zLrodataAfterBss; bool zNoBtCfi; diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp index 21d228e..91e11bc 100644 --- a/lld/ELF/Driver.cpp +++ b/lld/ELF/Driver.cpp @@ -1625,6 +1625,8 @@ static void readConfigs(Ctx &ctx, opt::InputArgList &args) { ctx.arg.zIfuncNoplt = hasZOption(args, "ifunc-noplt"); ctx.arg.zInitfirst = hasZOption(args, "initfirst"); ctx.arg.zInterpose = hasZOption(args, "interpose"); + ctx.arg.zKeepDataSectionPrefix = getZFlag( + args, "keep-data-section-prefix", "nokeep-data-section-prefix", false); ctx.arg.zKeepTextSectionPrefix = getZFlag( args, "keep-text-section-prefix", "nokeep-text-section-prefix", false); ctx.arg.zLrodataAfterBss = diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp index 15909da..c3c0578 100644 --- a/lld/ELF/Writer.cpp +++ b/lld/ELF/Writer.cpp @@ -553,6 +553,19 @@ template <class ELFT> void Writer<ELFT>::addSectionSymbols() { } } +// Returns true if this is a variant of .data.rel.ro. +static bool isRelRoDataSection(Ctx &ctx, StringRef secName) { + if (!secName.consume_front(".data.rel.ro")) + return false; + if (secName.empty()) + return true; + // If -z keep-data-section-prefix is specified, additionally allow + // '.data.rel.ro.hot' and '.data.rel.ro.unlikely'. + if (ctx.arg.zKeepDataSectionPrefix) + return secName == ".hot" || secName == ".unlikely"; + return false; +} + // Today's loaders have a feature to make segments read-only after // processing dynamic relocations to enhance security. PT_GNU_RELRO // is defined for that. @@ -629,7 +642,7 @@ static bool isRelroSection(Ctx &ctx, const OutputSection *sec) { // magic section names. StringRef s = sec->name; - bool abiAgnostic = s == ".data.rel.ro" || s == ".bss.rel.ro" || + bool abiAgnostic = isRelRoDataSection(ctx, s) || s == ".bss.rel.ro" || s == ".ctors" || s == ".dtors" || s == ".jcr" || s == ".eh_frame" || s == ".fini_array" || s == ".init_array" || s == ".preinit_array"; diff --git a/lld/test/ELF/keep-data-section-prefix.s b/lld/test/ELF/keep-data-section-prefix.s new file mode 100644 index 0000000..4b08f53 --- /dev/null +++ b/lld/test/ELF/keep-data-section-prefix.s @@ -0,0 +1,89 @@ +# REQUIRES: x86 + +# RUN: rm -rf %t && split-file %s %t && cd %t + +# RUN: llvm-mc -filetype=obj -triple=x86_64 a.s -o a.o + +# RUN: ld.lld -z keep-data-section-prefix -T x.lds a.o -o out1 +# RUN: llvm-readelf -l out1 | FileCheck --check-prefixes=SEG,LS %s +# RUN: llvm-readelf -S out1 | FileCheck %s --check-prefix=CHECK-LS + +# RUN: ld.lld -z keep-data-section-prefix a.o -o out2 +# RUN: llvm-readelf -l out2 | FileCheck --check-prefixes=SEG,PRE %s +# RUN: llvm-readelf -S out2 | FileCheck %s --check-prefix=CHECK-PRE + +# RUN: ld.lld a.o -o out3 +# RUN: llvm-readelf -l out3 | FileCheck --check-prefixes=SEG,PRE %s +# RUN: llvm-readelf -S out3 | FileCheck %s --check-prefix=CHECK-PRE + +# RUN: not ld.lld -T x.lds a.o 2>&1 | FileCheck %s +# CHECK: error: section: .relro_padding is not contiguous with other relro sections + +## The first RW PT_LOAD segment has FileSiz 0x126f (0x1000 + 0x200 + 0x60 + 0xf), +## and its p_offset p_vaddr p_paddr p_filesz should match PT_GNU_RELRO. +# Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align +# SEG: LOAD 0x0001c8 0x00000000002011c8 0x00000000002011c8 0x000001 0x000001 R E 0x1000 +# SEG-NEXT: LOAD 0x0001c9 0x00000000002021c9 0x00000000002021c9 0x00126f 0x001e37 RW 0x1000 +# SEG-NEXT: LOAD 0x001438 0x0000000000204438 0x0000000000204438 0x000001 0x000002 RW 0x1000 +# SEG-NEXT: GNU_RELRO 0x0001c9 0x00000000002021c9 0x00000000002021c9 0x00126f 0x001e37 R 0x1 +# SEG-NEXT: GNU_STACK 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RW 0x0 + +## Input to output mapping per linker script +## .data.rel.ro.split -> .data.rel.ro +## .data.rel.ro -> .data.rel.ro +## .data.rel.ro.hot -> .data.rel.ro.hot +## .data.rel.ro.unlikely -> .data.rel.ro.unlikely +# LS: .text +# LS-NEXT: .data.rel.ro.hot .data.rel.ro .data.rel.ro.unlikely .relro_padding +# LS-NEXT: .data .bss + +# [Nr] Name Type Address Off Size +# CHECK-LS: .data.rel.ro.hot PROGBITS 00000000002021c9 0001c9 00000f +# CHECK-LS-NEXT: .data.rel.ro PROGBITS 00000000002021d8 0001d8 000260 +# CHECK-LS-NEXT: .data.rel.ro.unlikely PROGBITS 0000000000202438 000438 001000 +# CHECK-LS-NEXT: .relro_padding NOBITS 0000000000203438 001438 000bc8 +# CHECK-LS-NEXT: .data PROGBITS 0000000000204438 001438 000001 +# CHECK-LS-NEXT: .bss NOBITS 0000000000204439 001439 000001 + +## Linker script is not provided to map data sections. +## So all input sections with prefix .data.rel.ro will map to .data.rel.ro in the output. +# PRE: .text +# PRE-NEXT: .data.rel.ro .relro_padding +# PRE-NEXT: .data .bss + +# [Nr] Name Type Address Off Size +# CHECK-PRE: .data.rel.ro PROGBITS 00000000002021c9 0001c9 00126f +# CHECK-PRE-NEXT: .relro_padding NOBITS 0000000000203438 001438 000bc8 +# CHECK-PRE-NEXT: .data PROGBITS 0000000000204438 001438 000001 +# CHECK-PRE-NEXT: .bss NOBITS 0000000000204439 001439 000001 + +#--- x.lds +SECTIONS { + .data.rel.ro.hot : { *(.data.rel.ro.hot) } + .data.rel.ro : { .data.rel.ro } + .data.rel.ro.unlikely : { *(.data.rel.ro.unlikely) } +} INSERT AFTER .text + + +#--- a.s +.globl _start +_start: + ret + +.section .data.rel.ro.hot, "aw" +.space 15 + +.section .data.rel.ro, "aw" +.space 96 + +.section .data.rel.ro.split,"aw" +.space 512 + +.section .data.rel.ro.unlikely, "aw" +.space 4096 + +.section .data, "aw" +.space 1 + +.section .bss, "aw" +.space 1 |