1728405b13
+ When all relocatable files contain a `.note.gnu.property` section (with `NT_GNU_PROPERTY_TYPE_0` notes) which contains a `GNU_PROPERTY_RISCV_FEATURE_1_AND` property in which the `GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED`/`GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG`/`GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_SS` bit is set: + The output file will contain a `.note.gnu.property` section with the bit set + A `PT_GNU_PROPERTY` program header is created to encompass the `.note.gnu.property` section + If `-z zicfilp-unlabeled-report=[warning|error]`/`-z zicfilp-func-sig-report=[warning|error]`/`-z zicfiss-report=[warning|error]` is specified, the linker will report a warning or error for any relocatable file lacking the feature bit RISC-V Zicfilp/Zicfiss features indicate their adoptions as bits in the `.note.gnu.property` section of ELF files. This patch enables LLD to process the information correctly by parsing, checking and merging the bits from all input ELF files and writing the merged result to the output ELF file. These feature bits are encoded as a mask in each input ELF files and intended to be "and"-ed together to check that all input files support a particular feature. For RISC-V Zicfilp features, there are 2 conflicting bits allocated: `GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED` and `GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG`. They represent the adoption of the forward edge protection of control-flow integrity with the "unlabeled" or "func-sig" policy. Since these 2 policies conflicts with each other, these 2 bits also conflict with each other. This patch adds the `-z zicfilp-unlabeled-report=[none|warning|error]` and `-z zicfilp-func-sig-report=[none|warning|error]` commandline options to make LLD report files that do not have the expected bits toggled on. For RISC-V Zicfiss feature, there's only one bit allocated: `GNU_PROPERTY_RISCV_FEATURE_1_CFI_SS`. This bit indicates that the ELF file supports Zicfiss-based shadow stack. This patch adds the `-z zicfiss-report=[none|warning|error]` commandline option to make LLD report files that do not have the expected bit toggled on. The adoption of the `.note.gnu.property` section for RISC-V targets can be found in the psABI PR <https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/417> (`CFI_LP_UNLABELED` and `CFI_SS`) and PR <https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/434> (`CFI_LP_FUNC_SIG`).
LLVM Linker (lld)
This directory and its subdirectories contain source code for the LLVM Linker, a modular cross platform linker which is built as part of the LLVM compiler infrastructure project.
lld is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt.
Benchmarking
In order to make sure various developers can evaluate patches over the same tests, we create a collection of self contained programs.
It is hosted at https://s3-us-west-2.amazonaws.com/linker-tests/lld-speed-test.tar.xz
The current sha256 is 10eec685463d5a8bbf08d77f4ca96282161d396c65bd97dc99dbde644a31610f.