Staticlib rename internal symbols by cezarbbb · Pull Request #156950 · rust-lang/rust

cezarbbb · 2026-05-26T03:37:56Z

Follow-up to #155338.

-Zstaticlib-rename-internal-symbols appends a crate-specific suffix (_rs{StableCrateId}) to non-exported symbols, resolving duplicate symbol conflicts when linking multiple Rust staticlibs into the same binary.

The implementation collects all defined GLOBAL/WEAK symbol names not in the exported set across all .o files, then renames them by extending the strtab and patching symbol name offsets. When combined with -Zstaticlib-hide-internal-symbols, the renamed symbols also receive STV_HIDDEN visibility.

Supported on ELF targets (Linux, BSD, etc.) and Apple targets (macOS, iOS, etc.). On unsupported targets (Windows), a warning is emitted and the flag has no effect.

r?@bjorn3 @petrochenkov

petrochenkov · 2026-05-26T11:04:39Z

Blocked on #155338.
@rustbot blocked

MicroDroid · 2026-06-03T10:30:07Z

btw if this underwent a lot of changes and needs re-testing, I'm up for it (I compile Rust to 6 targets).

cezarbbb · 2026-06-04T08:31:14Z

btw if this underwent a lot of changes and needs re-testing, I'm up for it (I compile Rust to 6 targets).

Functionally, there shouldn't be any changes; it's mostly more "Rusty" modifications. After #155338 is landed, I will rebase the current PR, and you can test it after that.

@bjorn3

… r=petrochenkov Staticlib hide internal symbols According to issue rust-lang#104707, when building a staticlib, all Rust internal symbols — mangled symbols, `#[rustc_std_internal_symbol]` items, allocator shims, etc. — leak out of the static archive. In contrast, cdylib correctly exports only `#[no_mangle]` symbols via a linker version script. `-Zstaticlib-hide-internal-symbols` directly post-processes ELF object files in the archive: parsing the `SHT_SYMTAB` sections and setting `STV_HIDDEN` visibility on any `GLOBAL/WEAK` defined symbol that is not in the exported symbol set, without changing the binding. This is an in-place modification (only writing the st_other byte per matching entry), with zero overhead. Supported on ELF targets (Linux, BSD, etc.) and Apple targets (macOS, iOS, etc.). On unsupported targets (Windows), a warning is emitted and the flag has no effect. **Update**: The rename counterpart (`-Zstaticlib-rename-internal-symbols`) is in rust-lang#156950. The test code are as follows: 1.a std rust staticlib: ```rust use std::collections::HashMap; use std::panic::{catch_unwind, AssertUnwindSafe}; #[no_mangle] pub extern "C" fn my_add(a: i32, b: i32) -> i32 { a + b } #[no_mangle] pub extern "C" fn my_hash_lookup(key: u64) -> u64 { let mut map = HashMap::new(); for i in 0..100u64 { map.insert(i, i.wrapping_mul(2654435761)); } *map.get(&key).unwrap_or(&0) } pub fn internal_reverse(s: &str) -> String { s.chars().rev().collect() } #[no_mangle] pub extern "C" fn my_format_number(n: i32) -> i32 { let s = format!("number: {}", n); s.len() as i32 } #[no_mangle] pub extern "C" fn my_safe_div(a: i32, b: i32) -> i32 { match catch_unwind(AssertUnwindSafe(|| { if b == 0 { panic!("division by zero!"); } a / b })) { Ok(result) => result, Err(_) => -1, } } #[no_mangle] pub extern "C" fn my_uncaught_panic() { panic!("uncaught panic across FFI"); } ``` 1.b downstream c program: ```c extern int my_add(int a, int b); extern unsigned long my_hash_lookup(unsigned long key); extern int my_format_number(int n); extern int my_safe_div(int a, int b); extern void my_uncaught_panic(void); int main() { int failures = 0; if (my_add(10, 20) != 30) failures++; if (my_hash_lookup(5) != 5UL * 2654435761UL) failures++; if (my_format_number(42) != 10) failures++; if (my_safe_div(100, 5) != 20) failures++; if (my_safe_div(100, 0) != -1) failures++; pid_t pid = fork(); if (pid == 0) { alarm(5); my_uncaught_panic(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 1.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin 616K 584K 33K (5%) 246 5 241 lto_fat 525K 525K 0 (0%) 6 5 1 opt_s 1.7M 1.5M 204K (12%) 1735 5 1730 opt_z 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin_z 602K 570K 32K (5%) 246 5 241 lto_fat_z 514K 514K 0 (0%) 6 5 1 full 514K 514K 0 (0%) 6 5 1 ``` 1.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin 616K 599K 18K (2%) 246 5 241 lto_fat 525K 535K -1% (-1%) 6 5 1 opt_s 1.7M 1.5M 162K (9%) 1735 5 1730 opt_z 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin_z 602K 585K 18K (2%) 246 5 241 lto_fat_z 514K 524K -1% (-1%) 6 5 1 full 514K 523K -1% (-1%) 6 5 1 ``` 2.a no_std rust staticlib ```rust #![no_std] #![feature(core_intrinsics)] use core::panic::PanicInfo; #[panic_handler] fn panic(_info: &PanicInfo) -> ! { loop {} } #[no_mangle] pub extern "C" fn embedded_add(a: i32, b: i32) -> i32 { a.wrapping_add(b) } #[no_mangle] pub extern "C" fn embedded_checksum(data: *const u8, len: usize) -> u8 { if data.is_null() { return 0; } let slice = unsafe { core::slice::from_raw_parts(data, len) }; let mut sum: u8 = 0; for &byte in slice { sum = sum.wrapping_add(byte); } sum } fn internal_helper() -> i32 { 42 } #[no_mangle] pub extern "C" fn call_internal() -> i32 { internal_helper() } #[no_mangle] pub extern "C" fn embedded_trigger_abort() { core::intrinsics::abort(); } ``` 2.b downstream c program ```c extern int embedded_add(int a, int b); extern unsigned char embedded_checksum(const unsigned char *data, unsigned long len); extern int call_internal(void); extern void embedded_trigger_abort(void); int main() { int failures = 0; if (embedded_add(10, 20) != 30) failures++; unsigned char data[] = {1, 2, 3}; if (embedded_checksum(data, 3) != 6) failures++; if (call_internal() != 42) failures++; pid_t pid = fork(); if (pid == 0) { embedded_trigger_abort(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 2.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 429K 56K (11%) 490 4 486 lto_thin 180K 180K 0 (0%) 4 4 0 lto_fat 179K 179K 0 (0%) 4 4 0 opt_s 485K 429K 56K (11%) 490 4 486 opt_z 485K 429K 56K (11%) 490 4 486 lto_thin_z 180K 180K 0 (0%) 4 4 0 lto_fat_z 179K 179K 0 (0%) 4 4 0 full 179K 179K 0 (0%) 4 4 0 ``` 2.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 447K 39K (7%) 490 4 486 lto_thin 180K 189K -5% (-5%) 4 4 0 lto_fat 179K 189K -5% (-5%) 4 4 0 opt_s 485K 448K 38K (7%) 490 4 486 opt_z 485K 448K 38K (7%) 490 4 486 lto_thin_z 180K 189K -5% (-5%) 4 4 0 lto_fat_z 179K 189K -5% (-5%) 4 4 0 full 179K 189K -5% (-5%) 4 4 0 ``` Test results show that this compiler option is beneficial for scenarios where LTO cannot be enabled. r? @bjorn3 @petrochenkov

@bjorn3

… r=petrochenkov Staticlib hide internal symbols According to issue rust-lang#104707, when building a staticlib, all Rust internal symbols — mangled symbols, `#[rustc_std_internal_symbol]` items, allocator shims, etc. — leak out of the static archive. In contrast, cdylib correctly exports only `#[no_mangle]` symbols via a linker version script. `-Zstaticlib-hide-internal-symbols` directly post-processes ELF object files in the archive: parsing the `SHT_SYMTAB` sections and setting `STV_HIDDEN` visibility on any `GLOBAL/WEAK` defined symbol that is not in the exported symbol set, without changing the binding. This is an in-place modification (only writing the st_other byte per matching entry), with zero overhead. Supported on ELF targets (Linux, BSD, etc.) and Apple targets (macOS, iOS, etc.). On unsupported targets (Windows), a warning is emitted and the flag has no effect. **Update**: The rename counterpart (`-Zstaticlib-rename-internal-symbols`) is in rust-lang#156950. The test code are as follows: 1.a std rust staticlib: ```rust use std::collections::HashMap; use std::panic::{catch_unwind, AssertUnwindSafe}; #[no_mangle] pub extern "C" fn my_add(a: i32, b: i32) -> i32 { a + b } #[no_mangle] pub extern "C" fn my_hash_lookup(key: u64) -> u64 { let mut map = HashMap::new(); for i in 0..100u64 { map.insert(i, i.wrapping_mul(2654435761)); } *map.get(&key).unwrap_or(&0) } pub fn internal_reverse(s: &str) -> String { s.chars().rev().collect() } #[no_mangle] pub extern "C" fn my_format_number(n: i32) -> i32 { let s = format!("number: {}", n); s.len() as i32 } #[no_mangle] pub extern "C" fn my_safe_div(a: i32, b: i32) -> i32 { match catch_unwind(AssertUnwindSafe(|| { if b == 0 { panic!("division by zero!"); } a / b })) { Ok(result) => result, Err(_) => -1, } } #[no_mangle] pub extern "C" fn my_uncaught_panic() { panic!("uncaught panic across FFI"); } ``` 1.b downstream c program: ```c extern int my_add(int a, int b); extern unsigned long my_hash_lookup(unsigned long key); extern int my_format_number(int n); extern int my_safe_div(int a, int b); extern void my_uncaught_panic(void); int main() { int failures = 0; if (my_add(10, 20) != 30) failures++; if (my_hash_lookup(5) != 5UL * 2654435761UL) failures++; if (my_format_number(42) != 10) failures++; if (my_safe_div(100, 5) != 20) failures++; if (my_safe_div(100, 0) != -1) failures++; pid_t pid = fork(); if (pid == 0) { alarm(5); my_uncaught_panic(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 1.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin 616K 584K 33K (5%) 246 5 241 lto_fat 525K 525K 0 (0%) 6 5 1 opt_s 1.7M 1.5M 204K (12%) 1735 5 1730 opt_z 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin_z 602K 570K 32K (5%) 246 5 241 lto_fat_z 514K 514K 0 (0%) 6 5 1 full 514K 514K 0 (0%) 6 5 1 ``` 1.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin 616K 599K 18K (2%) 246 5 241 lto_fat 525K 535K -1% (-1%) 6 5 1 opt_s 1.7M 1.5M 162K (9%) 1735 5 1730 opt_z 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin_z 602K 585K 18K (2%) 246 5 241 lto_fat_z 514K 524K -1% (-1%) 6 5 1 full 514K 523K -1% (-1%) 6 5 1 ``` 2.a no_std rust staticlib ```rust #![no_std] #![feature(core_intrinsics)] use core::panic::PanicInfo; #[panic_handler] fn panic(_info: &PanicInfo) -> ! { loop {} } #[no_mangle] pub extern "C" fn embedded_add(a: i32, b: i32) -> i32 { a.wrapping_add(b) } #[no_mangle] pub extern "C" fn embedded_checksum(data: *const u8, len: usize) -> u8 { if data.is_null() { return 0; } let slice = unsafe { core::slice::from_raw_parts(data, len) }; let mut sum: u8 = 0; for &byte in slice { sum = sum.wrapping_add(byte); } sum } fn internal_helper() -> i32 { 42 } #[no_mangle] pub extern "C" fn call_internal() -> i32 { internal_helper() } #[no_mangle] pub extern "C" fn embedded_trigger_abort() { core::intrinsics::abort(); } ``` 2.b downstream c program ```c extern int embedded_add(int a, int b); extern unsigned char embedded_checksum(const unsigned char *data, unsigned long len); extern int call_internal(void); extern void embedded_trigger_abort(void); int main() { int failures = 0; if (embedded_add(10, 20) != 30) failures++; unsigned char data[] = {1, 2, 3}; if (embedded_checksum(data, 3) != 6) failures++; if (call_internal() != 42) failures++; pid_t pid = fork(); if (pid == 0) { embedded_trigger_abort(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 2.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 429K 56K (11%) 490 4 486 lto_thin 180K 180K 0 (0%) 4 4 0 lto_fat 179K 179K 0 (0%) 4 4 0 opt_s 485K 429K 56K (11%) 490 4 486 opt_z 485K 429K 56K (11%) 490 4 486 lto_thin_z 180K 180K 0 (0%) 4 4 0 lto_fat_z 179K 179K 0 (0%) 4 4 0 full 179K 179K 0 (0%) 4 4 0 ``` 2.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 447K 39K (7%) 490 4 486 lto_thin 180K 189K -5% (-5%) 4 4 0 lto_fat 179K 189K -5% (-5%) 4 4 0 opt_s 485K 448K 38K (7%) 490 4 486 opt_z 485K 448K 38K (7%) 490 4 486 lto_thin_z 180K 189K -5% (-5%) 4 4 0 lto_fat_z 179K 189K -5% (-5%) 4 4 0 full 179K 189K -5% (-5%) 4 4 0 ``` Test results show that this compiler option is beneficial for scenarios where LTO cannot be enabled. r? @bjorn3 @petrochenkov

@bjorn3

… r=petrochenkov Staticlib hide internal symbols According to issue rust-lang#104707, when building a staticlib, all Rust internal symbols — mangled symbols, `#[rustc_std_internal_symbol]` items, allocator shims, etc. — leak out of the static archive. In contrast, cdylib correctly exports only `#[no_mangle]` symbols via a linker version script. `-Zstaticlib-hide-internal-symbols` directly post-processes ELF object files in the archive: parsing the `SHT_SYMTAB` sections and setting `STV_HIDDEN` visibility on any `GLOBAL/WEAK` defined symbol that is not in the exported symbol set, without changing the binding. This is an in-place modification (only writing the st_other byte per matching entry), with zero overhead. Supported on ELF targets (Linux, BSD, etc.) and Apple targets (macOS, iOS, etc.). On unsupported targets (Windows), a warning is emitted and the flag has no effect. **Update**: The rename counterpart (`-Zstaticlib-rename-internal-symbols`) is in rust-lang#156950. The test code are as follows: 1.a std rust staticlib: ```rust use std::collections::HashMap; use std::panic::{catch_unwind, AssertUnwindSafe}; #[no_mangle] pub extern "C" fn my_add(a: i32, b: i32) -> i32 { a + b } #[no_mangle] pub extern "C" fn my_hash_lookup(key: u64) -> u64 { let mut map = HashMap::new(); for i in 0..100u64 { map.insert(i, i.wrapping_mul(2654435761)); } *map.get(&key).unwrap_or(&0) } pub fn internal_reverse(s: &str) -> String { s.chars().rev().collect() } #[no_mangle] pub extern "C" fn my_format_number(n: i32) -> i32 { let s = format!("number: {}", n); s.len() as i32 } #[no_mangle] pub extern "C" fn my_safe_div(a: i32, b: i32) -> i32 { match catch_unwind(AssertUnwindSafe(|| { if b == 0 { panic!("division by zero!"); } a / b })) { Ok(result) => result, Err(_) => -1, } } #[no_mangle] pub extern "C" fn my_uncaught_panic() { panic!("uncaught panic across FFI"); } ``` 1.b downstream c program: ```c extern int my_add(int a, int b); extern unsigned long my_hash_lookup(unsigned long key); extern int my_format_number(int n); extern int my_safe_div(int a, int b); extern void my_uncaught_panic(void); int main() { int failures = 0; if (my_add(10, 20) != 30) failures++; if (my_hash_lookup(5) != 5UL * 2654435761UL) failures++; if (my_format_number(42) != 10) failures++; if (my_safe_div(100, 5) != 20) failures++; if (my_safe_div(100, 0) != -1) failures++; pid_t pid = fork(); if (pid == 0) { alarm(5); my_uncaught_panic(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 1.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin 616K 584K 33K (5%) 246 5 241 lto_fat 525K 525K 0 (0%) 6 5 1 opt_s 1.7M 1.5M 204K (12%) 1735 5 1730 opt_z 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin_z 602K 570K 32K (5%) 246 5 241 lto_fat_z 514K 514K 0 (0%) 6 5 1 full 514K 514K 0 (0%) 6 5 1 ``` 1.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin 616K 599K 18K (2%) 246 5 241 lto_fat 525K 535K -1% (-1%) 6 5 1 opt_s 1.7M 1.5M 162K (9%) 1735 5 1730 opt_z 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin_z 602K 585K 18K (2%) 246 5 241 lto_fat_z 514K 524K -1% (-1%) 6 5 1 full 514K 523K -1% (-1%) 6 5 1 ``` 2.a no_std rust staticlib ```rust #![no_std] #![feature(core_intrinsics)] use core::panic::PanicInfo; #[panic_handler] fn panic(_info: &PanicInfo) -> ! { loop {} } #[no_mangle] pub extern "C" fn embedded_add(a: i32, b: i32) -> i32 { a.wrapping_add(b) } #[no_mangle] pub extern "C" fn embedded_checksum(data: *const u8, len: usize) -> u8 { if data.is_null() { return 0; } let slice = unsafe { core::slice::from_raw_parts(data, len) }; let mut sum: u8 = 0; for &byte in slice { sum = sum.wrapping_add(byte); } sum } fn internal_helper() -> i32 { 42 } #[no_mangle] pub extern "C" fn call_internal() -> i32 { internal_helper() } #[no_mangle] pub extern "C" fn embedded_trigger_abort() { core::intrinsics::abort(); } ``` 2.b downstream c program ```c extern int embedded_add(int a, int b); extern unsigned char embedded_checksum(const unsigned char *data, unsigned long len); extern int call_internal(void); extern void embedded_trigger_abort(void); int main() { int failures = 0; if (embedded_add(10, 20) != 30) failures++; unsigned char data[] = {1, 2, 3}; if (embedded_checksum(data, 3) != 6) failures++; if (call_internal() != 42) failures++; pid_t pid = fork(); if (pid == 0) { embedded_trigger_abort(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 2.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 429K 56K (11%) 490 4 486 lto_thin 180K 180K 0 (0%) 4 4 0 lto_fat 179K 179K 0 (0%) 4 4 0 opt_s 485K 429K 56K (11%) 490 4 486 opt_z 485K 429K 56K (11%) 490 4 486 lto_thin_z 180K 180K 0 (0%) 4 4 0 lto_fat_z 179K 179K 0 (0%) 4 4 0 full 179K 179K 0 (0%) 4 4 0 ``` 2.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 447K 39K (7%) 490 4 486 lto_thin 180K 189K -5% (-5%) 4 4 0 lto_fat 179K 189K -5% (-5%) 4 4 0 opt_s 485K 448K 38K (7%) 490 4 486 opt_z 485K 448K 38K (7%) 490 4 486 lto_thin_z 180K 189K -5% (-5%) 4 4 0 lto_fat_z 179K 189K -5% (-5%) 4 4 0 full 179K 189K -5% (-5%) 4 4 0 ``` Test results show that this compiler option is beneficial for scenarios where LTO cannot be enabled. r? @bjorn3 @petrochenkov

@bjorn3

… r=petrochenkov Staticlib hide internal symbols According to issue rust-lang#104707, when building a staticlib, all Rust internal symbols — mangled symbols, `#[rustc_std_internal_symbol]` items, allocator shims, etc. — leak out of the static archive. In contrast, cdylib correctly exports only `#[no_mangle]` symbols via a linker version script. `-Zstaticlib-hide-internal-symbols` directly post-processes ELF object files in the archive: parsing the `SHT_SYMTAB` sections and setting `STV_HIDDEN` visibility on any `GLOBAL/WEAK` defined symbol that is not in the exported symbol set, without changing the binding. This is an in-place modification (only writing the st_other byte per matching entry), with zero overhead. Supported on ELF targets (Linux, BSD, etc.) and Apple targets (macOS, iOS, etc.). On unsupported targets (Windows), a warning is emitted and the flag has no effect. **Update**: The rename counterpart (`-Zstaticlib-rename-internal-symbols`) is in rust-lang#156950. The test code are as follows: 1.a std rust staticlib: ```rust use std::collections::HashMap; use std::panic::{catch_unwind, AssertUnwindSafe}; #[no_mangle] pub extern "C" fn my_add(a: i32, b: i32) -> i32 { a + b } #[no_mangle] pub extern "C" fn my_hash_lookup(key: u64) -> u64 { let mut map = HashMap::new(); for i in 0..100u64 { map.insert(i, i.wrapping_mul(2654435761)); } *map.get(&key).unwrap_or(&0) } pub fn internal_reverse(s: &str) -> String { s.chars().rev().collect() } #[no_mangle] pub extern "C" fn my_format_number(n: i32) -> i32 { let s = format!("number: {}", n); s.len() as i32 } #[no_mangle] pub extern "C" fn my_safe_div(a: i32, b: i32) -> i32 { match catch_unwind(AssertUnwindSafe(|| { if b == 0 { panic!("division by zero!"); } a / b })) { Ok(result) => result, Err(_) => -1, } } #[no_mangle] pub extern "C" fn my_uncaught_panic() { panic!("uncaught panic across FFI"); } ``` 1.b downstream c program: ```c extern int my_add(int a, int b); extern unsigned long my_hash_lookup(unsigned long key); extern int my_format_number(int n); extern int my_safe_div(int a, int b); extern void my_uncaught_panic(void); int main() { int failures = 0; if (my_add(10, 20) != 30) failures++; if (my_hash_lookup(5) != 5UL * 2654435761UL) failures++; if (my_format_number(42) != 10) failures++; if (my_safe_div(100, 5) != 20) failures++; if (my_safe_div(100, 0) != -1) failures++; pid_t pid = fork(); if (pid == 0) { alarm(5); my_uncaught_panic(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 1.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin 616K 584K 33K (5%) 246 5 241 lto_fat 525K 525K 0 (0%) 6 5 1 opt_s 1.7M 1.5M 204K (12%) 1735 5 1730 opt_z 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin_z 602K 570K 32K (5%) 246 5 241 lto_fat_z 514K 514K 0 (0%) 6 5 1 full 514K 514K 0 (0%) 6 5 1 ``` 1.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin 616K 599K 18K (2%) 246 5 241 lto_fat 525K 535K -1% (-1%) 6 5 1 opt_s 1.7M 1.5M 162K (9%) 1735 5 1730 opt_z 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin_z 602K 585K 18K (2%) 246 5 241 lto_fat_z 514K 524K -1% (-1%) 6 5 1 full 514K 523K -1% (-1%) 6 5 1 ``` 2.a no_std rust staticlib ```rust #![no_std] #![feature(core_intrinsics)] use core::panic::PanicInfo; #[panic_handler] fn panic(_info: &PanicInfo) -> ! { loop {} } #[no_mangle] pub extern "C" fn embedded_add(a: i32, b: i32) -> i32 { a.wrapping_add(b) } #[no_mangle] pub extern "C" fn embedded_checksum(data: *const u8, len: usize) -> u8 { if data.is_null() { return 0; } let slice = unsafe { core::slice::from_raw_parts(data, len) }; let mut sum: u8 = 0; for &byte in slice { sum = sum.wrapping_add(byte); } sum } fn internal_helper() -> i32 { 42 } #[no_mangle] pub extern "C" fn call_internal() -> i32 { internal_helper() } #[no_mangle] pub extern "C" fn embedded_trigger_abort() { core::intrinsics::abort(); } ``` 2.b downstream c program ```c extern int embedded_add(int a, int b); extern unsigned char embedded_checksum(const unsigned char *data, unsigned long len); extern int call_internal(void); extern void embedded_trigger_abort(void); int main() { int failures = 0; if (embedded_add(10, 20) != 30) failures++; unsigned char data[] = {1, 2, 3}; if (embedded_checksum(data, 3) != 6) failures++; if (call_internal() != 42) failures++; pid_t pid = fork(); if (pid == 0) { embedded_trigger_abort(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 2.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 429K 56K (11%) 490 4 486 lto_thin 180K 180K 0 (0%) 4 4 0 lto_fat 179K 179K 0 (0%) 4 4 0 opt_s 485K 429K 56K (11%) 490 4 486 opt_z 485K 429K 56K (11%) 490 4 486 lto_thin_z 180K 180K 0 (0%) 4 4 0 lto_fat_z 179K 179K 0 (0%) 4 4 0 full 179K 179K 0 (0%) 4 4 0 ``` 2.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 447K 39K (7%) 490 4 486 lto_thin 180K 189K -5% (-5%) 4 4 0 lto_fat 179K 189K -5% (-5%) 4 4 0 opt_s 485K 448K 38K (7%) 490 4 486 opt_z 485K 448K 38K (7%) 490 4 486 lto_thin_z 180K 189K -5% (-5%) 4 4 0 lto_fat_z 179K 189K -5% (-5%) 4 4 0 full 179K 189K -5% (-5%) 4 4 0 ``` Test results show that this compiler option is beneficial for scenarios where LTO cannot be enabled. r? @bjorn3 @petrochenkov

@bjorn3

Rollup merge of #155338 - cezarbbb:staticlib-symbol-hygiene, r=petrochenkov Staticlib hide internal symbols According to issue #104707, when building a staticlib, all Rust internal symbols — mangled symbols, `#[rustc_std_internal_symbol]` items, allocator shims, etc. — leak out of the static archive. In contrast, cdylib correctly exports only `#[no_mangle]` symbols via a linker version script. `-Zstaticlib-hide-internal-symbols` directly post-processes ELF object files in the archive: parsing the `SHT_SYMTAB` sections and setting `STV_HIDDEN` visibility on any `GLOBAL/WEAK` defined symbol that is not in the exported symbol set, without changing the binding. This is an in-place modification (only writing the st_other byte per matching entry), with zero overhead. Supported on ELF targets (Linux, BSD, etc.) and Apple targets (macOS, iOS, etc.). On unsupported targets (Windows), a warning is emitted and the flag has no effect. **Update**: The rename counterpart (`-Zstaticlib-rename-internal-symbols`) is in #156950. The test code are as follows: 1.a std rust staticlib: ```rust use std::collections::HashMap; use std::panic::{catch_unwind, AssertUnwindSafe}; #[no_mangle] pub extern "C" fn my_add(a: i32, b: i32) -> i32 { a + b } #[no_mangle] pub extern "C" fn my_hash_lookup(key: u64) -> u64 { let mut map = HashMap::new(); for i in 0..100u64 { map.insert(i, i.wrapping_mul(2654435761)); } *map.get(&key).unwrap_or(&0) } pub fn internal_reverse(s: &str) -> String { s.chars().rev().collect() } #[no_mangle] pub extern "C" fn my_format_number(n: i32) -> i32 { let s = format!("number: {}", n); s.len() as i32 } #[no_mangle] pub extern "C" fn my_safe_div(a: i32, b: i32) -> i32 { match catch_unwind(AssertUnwindSafe(|| { if b == 0 { panic!("division by zero!"); } a / b })) { Ok(result) => result, Err(_) => -1, } } #[no_mangle] pub extern "C" fn my_uncaught_panic() { panic!("uncaught panic across FFI"); } ``` 1.b downstream c program: ```c extern int my_add(int a, int b); extern unsigned long my_hash_lookup(unsigned long key); extern int my_format_number(int n); extern int my_safe_div(int a, int b); extern void my_uncaught_panic(void); int main() { int failures = 0; if (my_add(10, 20) != 30) failures++; if (my_hash_lookup(5) != 5UL * 2654435761UL) failures++; if (my_format_number(42) != 10) failures++; if (my_safe_div(100, 5) != 20) failures++; if (my_safe_div(100, 0) != -1) failures++; pid_t pid = fork(); if (pid == 0) { alarm(5); my_uncaught_panic(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 1.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin 616K 584K 33K (5%) 246 5 241 lto_fat 525K 525K 0 (0%) 6 5 1 opt_s 1.7M 1.5M 204K (12%) 1735 5 1730 opt_z 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin_z 602K 570K 32K (5%) 246 5 241 lto_fat_z 514K 514K 0 (0%) 6 5 1 full 514K 514K 0 (0%) 6 5 1 ``` 1.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin 616K 599K 18K (2%) 246 5 241 lto_fat 525K 535K -1% (-1%) 6 5 1 opt_s 1.7M 1.5M 162K (9%) 1735 5 1730 opt_z 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin_z 602K 585K 18K (2%) 246 5 241 lto_fat_z 514K 524K -1% (-1%) 6 5 1 full 514K 523K -1% (-1%) 6 5 1 ``` 2.a no_std rust staticlib ```rust #![no_std] #![feature(core_intrinsics)] use core::panic::PanicInfo; #[panic_handler] fn panic(_info: &PanicInfo) -> ! { loop {} } #[no_mangle] pub extern "C" fn embedded_add(a: i32, b: i32) -> i32 { a.wrapping_add(b) } #[no_mangle] pub extern "C" fn embedded_checksum(data: *const u8, len: usize) -> u8 { if data.is_null() { return 0; } let slice = unsafe { core::slice::from_raw_parts(data, len) }; let mut sum: u8 = 0; for &byte in slice { sum = sum.wrapping_add(byte); } sum } fn internal_helper() -> i32 { 42 } #[no_mangle] pub extern "C" fn call_internal() -> i32 { internal_helper() } #[no_mangle] pub extern "C" fn embedded_trigger_abort() { core::intrinsics::abort(); } ``` 2.b downstream c program ```c extern int embedded_add(int a, int b); extern unsigned char embedded_checksum(const unsigned char *data, unsigned long len); extern int call_internal(void); extern void embedded_trigger_abort(void); int main() { int failures = 0; if (embedded_add(10, 20) != 30) failures++; unsigned char data[] = {1, 2, 3}; if (embedded_checksum(data, 3) != 6) failures++; if (call_internal() != 42) failures++; pid_t pid = fork(); if (pid == 0) { embedded_trigger_abort(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 2.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 429K 56K (11%) 490 4 486 lto_thin 180K 180K 0 (0%) 4 4 0 lto_fat 179K 179K 0 (0%) 4 4 0 opt_s 485K 429K 56K (11%) 490 4 486 opt_z 485K 429K 56K (11%) 490 4 486 lto_thin_z 180K 180K 0 (0%) 4 4 0 lto_fat_z 179K 179K 0 (0%) 4 4 0 full 179K 179K 0 (0%) 4 4 0 ``` 2.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 447K 39K (7%) 490 4 486 lto_thin 180K 189K -5% (-5%) 4 4 0 lto_fat 179K 189K -5% (-5%) 4 4 0 opt_s 485K 448K 38K (7%) 490 4 486 opt_z 485K 448K 38K (7%) 490 4 486 lto_thin_z 180K 189K -5% (-5%) 4 4 0 lto_fat_z 179K 189K -5% (-5%) 4 4 0 full 179K 189K -5% (-5%) 4 4 0 ``` Test results show that this compiler option is beneficial for scenarios where LTO cannot be enabled. r? @bjorn3 @petrochenkov

cezarbbb · 2026-06-09T03:21:49Z

Rebase the current PR to the branch after successfully merging PR #155338, and optimize and improve upon the issues encountered in PR #155338.

cezarbbb · 2026-06-09T04:44:39Z

Can we now remove the S-blocked label? @petrochenkov

petrochenkov · 2026-06-09T06:05:52Z

@rustbot ready

petrochenkov · 2026-06-09T16:38:55Z

I didn't look at the strtab building code in detail yet, probably in the next review round.
@rustbot author

@petrochenkov

…t, r=petrochenkov Move symbol hiding code to a new file Move the symbol visibility editing code (`apply_hide` and helpers) from `archive.rs` into a new `symbol_edit.rs` module. This is a pure code move with no functional changes — extracted to reduce the size of `archive.rs` and to provide a natural home for future symbol editing logic (e.g. renaming, rust-lang#156950). Requested in rust-lang#156950 (comment). r? @petrochenkov

cezarbbb · 2026-06-10T07:46:02Z

@rustbot ready

petrochenkov · 2026-06-10T10:36:09Z

I'll do the next review pass after this is rebased on #157691.
@rustbot blocked

@petrochenkov

…t, r=petrochenkov Move symbol hiding code to a new file Move the symbol visibility editing code (`apply_hide` and helpers) from `archive.rs` into a new `symbol_edit.rs` module. This is a pure code move with no functional changes — extracted to reduce the size of `archive.rs` and to provide a natural home for future symbol editing logic (e.g. renaming, rust-lang#156950). Requested in rust-lang#156950 (comment). r? @petrochenkov

@petrochenkov

…t, r=petrochenkov Move symbol hiding code to a new file Move the symbol visibility editing code (`apply_hide` and helpers) from `archive.rs` into a new `symbol_edit.rs` module. This is a pure code move with no functional changes — extracted to reduce the size of `archive.rs` and to provide a natural home for future symbol editing logic (e.g. renaming, rust-lang#156950). Requested in rust-lang#156950 (comment). r? @petrochenkov

@petrochenkov

…t, r=petrochenkov Move symbol hiding code to a new file Move the symbol visibility editing code (`apply_hide` and helpers) from `archive.rs` into a new `symbol_edit.rs` module. This is a pure code move with no functional changes — extracted to reduce the size of `archive.rs` and to provide a natural home for future symbol editing logic (e.g. renaming, rust-lang#156950). Requested in rust-lang#156950 (comment). r? @petrochenkov

@petrochenkov

…t, r=petrochenkov Move symbol hiding code to a new file Move the symbol visibility editing code (`apply_hide` and helpers) from `archive.rs` into a new `symbol_edit.rs` module. This is a pure code move with no functional changes — extracted to reduce the size of `archive.rs` and to provide a natural home for future symbol editing logic (e.g. renaming, rust-lang#156950). Requested in rust-lang#156950 (comment). r? @petrochenkov

@petrochenkov

…t, r=petrochenkov Move symbol hiding code to a new file Move the symbol visibility editing code (`apply_hide` and helpers) from `archive.rs` into a new `symbol_edit.rs` module. This is a pure code move with no functional changes — extracted to reduce the size of `archive.rs` and to provide a natural home for future symbol editing logic (e.g. renaming, rust-lang#156950). Requested in rust-lang#156950 (comment). r? @petrochenkov

@petrochenkov

…t, r=petrochenkov Move symbol hiding code to a new file Move the symbol visibility editing code (`apply_hide` and helpers) from `archive.rs` into a new `symbol_edit.rs` module. This is a pure code move with no functional changes — extracted to reduce the size of `archive.rs` and to provide a natural home for future symbol editing logic (e.g. renaming, rust-lang#156950). Requested in rust-lang#156950 (comment). r? @petrochenkov

@petrochenkov

…t, r=petrochenkov Move symbol hiding code to a new file Move the symbol visibility editing code (`apply_hide` and helpers) from `archive.rs` into a new `symbol_edit.rs` module. This is a pure code move with no functional changes — extracted to reduce the size of `archive.rs` and to provide a natural home for future symbol editing logic (e.g. renaming, rust-lang#156950). Requested in rust-lang#156950 (comment). r? @petrochenkov

@petrochenkov

…t, r=petrochenkov Move symbol hiding code to a new file Move the symbol visibility editing code (`apply_hide` and helpers) from `archive.rs` into a new `symbol_edit.rs` module. This is a pure code move with no functional changes — extracted to reduce the size of `archive.rs` and to provide a natural home for future symbol editing logic (e.g. renaming, rust-lang#156950). Requested in rust-lang#156950 (comment). r? @petrochenkov

@bjorn3

…henkov Staticlib hide internal symbols According to issue rust-lang/rust#104707, when building a staticlib, all Rust internal symbols — mangled symbols, `#[rustc_std_internal_symbol]` items, allocator shims, etc. — leak out of the static archive. In contrast, cdylib correctly exports only `#[no_mangle]` symbols via a linker version script. `-Zstaticlib-hide-internal-symbols` directly post-processes ELF object files in the archive: parsing the `SHT_SYMTAB` sections and setting `STV_HIDDEN` visibility on any `GLOBAL/WEAK` defined symbol that is not in the exported symbol set, without changing the binding. This is an in-place modification (only writing the st_other byte per matching entry), with zero overhead. Supported on ELF targets (Linux, BSD, etc.) and Apple targets (macOS, iOS, etc.). On unsupported targets (Windows), a warning is emitted and the flag has no effect. **Update**: The rename counterpart (`-Zstaticlib-rename-internal-symbols`) is in rust-lang/rust#156950. The test code are as follows: 1.a std rust staticlib: ```rust use std::collections::HashMap; use std::panic::{catch_unwind, AssertUnwindSafe}; #[no_mangle] pub extern "C" fn my_add(a: i32, b: i32) -> i32 { a + b } #[no_mangle] pub extern "C" fn my_hash_lookup(key: u64) -> u64 { let mut map = HashMap::new(); for i in 0..100u64 { map.insert(i, i.wrapping_mul(2654435761)); } *map.get(&key).unwrap_or(&0) } pub fn internal_reverse(s: &str) -> String { s.chars().rev().collect() } #[no_mangle] pub extern "C" fn my_format_number(n: i32) -> i32 { let s = format!("number: {}", n); s.len() as i32 } #[no_mangle] pub extern "C" fn my_safe_div(a: i32, b: i32) -> i32 { match catch_unwind(AssertUnwindSafe(|| { if b == 0 { panic!("division by zero!"); } a / b })) { Ok(result) => result, Err(_) => -1, } } #[no_mangle] pub extern "C" fn my_uncaught_panic() { panic!("uncaught panic across FFI"); } ``` 1.b downstream c program: ```c extern int my_add(int a, int b); extern unsigned long my_hash_lookup(unsigned long key); extern int my_format_number(int n); extern int my_safe_div(int a, int b); extern void my_uncaught_panic(void); int main() { int failures = 0; if (my_add(10, 20) != 30) failures++; if (my_hash_lookup(5) != 5UL * 2654435761UL) failures++; if (my_format_number(42) != 10) failures++; if (my_safe_div(100, 5) != 20) failures++; if (my_safe_div(100, 0) != -1) failures++; pid_t pid = fork(); if (pid == 0) { alarm(5); my_uncaught_panic(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 1.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin 616K 584K 33K (5%) 246 5 241 lto_fat 525K 525K 0 (0%) 6 5 1 opt_s 1.7M 1.5M 204K (12%) 1735 5 1730 opt_z 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin_z 602K 570K 32K (5%) 246 5 241 lto_fat_z 514K 514K 0 (0%) 6 5 1 full 514K 514K 0 (0%) 6 5 1 ``` 1.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin 616K 599K 18K (2%) 246 5 241 lto_fat 525K 535K -1% (-1%) 6 5 1 opt_s 1.7M 1.5M 162K (9%) 1735 5 1730 opt_z 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin_z 602K 585K 18K (2%) 246 5 241 lto_fat_z 514K 524K -1% (-1%) 6 5 1 full 514K 523K -1% (-1%) 6 5 1 ``` 2.a no_std rust staticlib ```rust #![no_std] #![feature(core_intrinsics)] use core::panic::PanicInfo; #[panic_handler] fn panic(_info: &PanicInfo) -> ! { loop {} } #[no_mangle] pub extern "C" fn embedded_add(a: i32, b: i32) -> i32 { a.wrapping_add(b) } #[no_mangle] pub extern "C" fn embedded_checksum(data: *const u8, len: usize) -> u8 { if data.is_null() { return 0; } let slice = unsafe { core::slice::from_raw_parts(data, len) }; let mut sum: u8 = 0; for &byte in slice { sum = sum.wrapping_add(byte); } sum } fn internal_helper() -> i32 { 42 } #[no_mangle] pub extern "C" fn call_internal() -> i32 { internal_helper() } #[no_mangle] pub extern "C" fn embedded_trigger_abort() { core::intrinsics::abort(); } ``` 2.b downstream c program ```c extern int embedded_add(int a, int b); extern unsigned char embedded_checksum(const unsigned char *data, unsigned long len); extern int call_internal(void); extern void embedded_trigger_abort(void); int main() { int failures = 0; if (embedded_add(10, 20) != 30) failures++; unsigned char data[] = {1, 2, 3}; if (embedded_checksum(data, 3) != 6) failures++; if (call_internal() != 42) failures++; pid_t pid = fork(); if (pid == 0) { embedded_trigger_abort(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 2.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 429K 56K (11%) 490 4 486 lto_thin 180K 180K 0 (0%) 4 4 0 lto_fat 179K 179K 0 (0%) 4 4 0 opt_s 485K 429K 56K (11%) 490 4 486 opt_z 485K 429K 56K (11%) 490 4 486 lto_thin_z 180K 180K 0 (0%) 4 4 0 lto_fat_z 179K 179K 0 (0%) 4 4 0 full 179K 179K 0 (0%) 4 4 0 ``` 2.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 447K 39K (7%) 490 4 486 lto_thin 180K 189K -5% (-5%) 4 4 0 lto_fat 179K 189K -5% (-5%) 4 4 0 opt_s 485K 448K 38K (7%) 490 4 486 opt_z 485K 448K 38K (7%) 490 4 486 lto_thin_z 180K 189K -5% (-5%) 4 4 0 lto_fat_z 179K 189K -5% (-5%) 4 4 0 full 179K 189K -5% (-5%) 4 4 0 ``` Test results show that this compiler option is beneficial for scenarios where LTO cannot be enabled. r? @bjorn3 @petrochenkov

@petrochenkov

Rollup merge of #157691 - cezarbbb:staticlib-move-symbol-edit, r=petrochenkov Move symbol hiding code to a new file Move the symbol visibility editing code (`apply_hide` and helpers) from `archive.rs` into a new `symbol_edit.rs` module. This is a pure code move with no functional changes — extracted to reduce the size of `archive.rs` and to provide a natural home for future symbol editing logic (e.g. renaming, #156950). Requested in #156950 (comment). r? @petrochenkov

rustbot · 2026-06-11T11:42:42Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

cezarbbb · 2026-06-11T11:44:09Z

This PR is rebased on PR #157691 now. @petrochenkov

petrochenkov · 2026-06-11T16:26:28Z

    };
-    ab.build(out_filename, exported_symbols);
+
+    let rename_suffix =


Suggested change

let rename_suffix =

let rename_suffix = rename.then(|| crate_info.symbol_rename_suffix.clone());

And this can be moved into the map below.

View changes since the review

petrochenkov · 2026-06-11T16:32:19Z

+                        let rename = rename_set
+                            .as_ref()
+                            .and_then(|set| sym.rename_suffix.as_deref().map(|s| (set, s)));
+                        let edited = apply_edits(data, &sym.exported, sym.hide, rename);


Suggested change

let edited = apply_edits(data, &sym.exported, sym.hide, rename);

Box::new(apply_edits(data, &sym.exported, sym.hide, rename));

IIRC I asked this on the previous PR already, Cow<[u8]> implements AsRef<[u8]> so you should be able to box it directly, without matching on the Cow, no?

View changes since the review

petrochenkov · 2026-06-11T16:47:01Z

+        }
+        let Ok(name_bytes) = sym.name(endian, strings) else { continue };
+        let Ok(name) = str::from_utf8(name_bytes) else { continue };
+        if !exported.contains(name) {


So we rename an undefined name if it is 1) not exported and 2) defined in some other object in the archive.
Yeah, I guess in this case there's no other choice than to collect all the defined non-exported names.

View changes since the review

petrochenkov · 2026-06-11T16:51:46Z

+                    }
+                }
+            }
+            Some(names)


Suggested change

Some(names)

Some((names, rename_suffix))

So you don't have to awkwardly add it later.

View changes since the review

petrochenkov · 2026-06-11T16:56:23Z

-
-    let data_ptr = data.as_ptr() as usize;
    let strings = symtab.strings();
+    let data_ptr = data.as_ptr() as usize;


Mega-nit: unnecessary change.

View changes since the review

petrochenkov · 2026-06-11T16:58:08Z

+        let sym_addr = sym as *const Elf::Sym as usize;
+        let is_defined = !sym.is_undefined(endian);
+
+        if hide && is_defined && !exported.contains(name) {


Suggested change

if hide && is_defined && !exported.contains(name) {

if hide && !sym.is_undefined(endian) && !exported.contains(name) {

Nit: is_defined used once.

View changes since the review

petrochenkov · 2026-06-11T17:03:19Z

-    Some(patches)
+    let mut result = if !renames.is_empty() {
+        let (_, suffix) = rename.unwrap();
+        elf_rebuild_strtab::<Elf>(data, &renames, suffix, &sections, header, endian)?


If strtab rebuilding can fail, then we should probably apply hiding first?
That's assuming we are working on best effort basis (I assume so because right now all the ELF parsing issues are just silently ignored).

View changes since the review

petrochenkov · 2026-06-11T17:08:33Z

+    }
+
+    for entry in renames {
+        let Some(&new_st_name) = rename_map.get(&entry.name) else { continue };


Suggested change

let Some(&new_st_name) = rename_map.get(&entry.name) else { continue };

let new_st_name = rename_map[entry.name];

The name must always be in the rename_map from what I see.

View changes since the review

petrochenkov · 2026-06-11T17:11:33Z

Most of the ELF comments apply to Mach-O too, as usual.
@rustbot author

rustbot assigned bjorn3 May 26, 2026

rustbot added A-run-make Area: port run-make Makefiles to rmake.rs S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels May 26, 2026

cezarbbb mentioned this pull request May 26, 2026

Staticlib hide internal symbols #155338

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add -Zstaticlib-rename-internal-symbols

27a996e

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	let rename_suffix =
	let rename_suffix = rename.then(\|\| crate_info.symbol_rename_suffix.clone());

	let edited = apply_edits(data, &sym.exported, sym.hide, rename);
	Box::new(apply_edits(data, &sym.exported, sym.hide, rename));

	if hide && is_defined && !exported.contains(name) {
	if hide && !sym.is_undefined(endian) && !exported.contains(name) {

	let Some(&new_st_name) = rename_map.get(&entry.name) else { continue };
	let new_st_name = rename_map[entry.name];

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