bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Auto merge of #105812 - ojeda:no-jump-tables, r=nikic

Browse source 
Add `-Zno-jump-tables`

This flag mimics GCC/Clang's `-fno-jump-tables` [1][2], which makes the codegen backend avoid generating jump tables when lowering switches.

In the case of LLVM, the `"no-jump-tables"="true"` function attribute is added to every function.

The kernel currently needs it for x86 when enabling IBT [3], as well as for Alpha (plus VDSO objects in MIPS/LoongArch).

[1] https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#index-fno-jump-tables
[2] https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-fjump-tables
[3] https://github.com/torvalds/linux/blob/v6.1/arch/x86/Makefile#L75-L83
This commit is contained in:
bors 2022-12-21 17:38:38 +00:00
commit a8207df49e
6 changed files with 69 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

2
compiler/rustc_session/src/options.rs
View file

@ -1421,6 +1421,8 @@ options! {
"run all passes except codegen; no output"),
no_generate_arange_section: bool = (false, parse_no_flag, [TRACKED],
"omit DWARF address ranges that give faster lookups"),
no_jump_tables: bool = (false, parse_no_flag, [TRACKED],
"disable the jump tables and lookup tables that can be generated from a switch case lowering"),
no_leak_check: bool = (false, parse_no_flag, [UNTRACKED],
"disable the 'leak check' for subtyping; unsound, but useful for tests"),
no_link: bool = (false, parse_no_flag, [TRACKED],