On 28.12.2024 22:18, Dimitry Andric wrote:
The branch main has been updated by dim:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=caab831338f4eeaa7455e981478be9fd414b7969

commit caab831338f4eeaa7455e981478be9fd414b7969
Author:     Dimitry Andric <d...@freebsd.org>
AuthorDate: 2024-12-28 21:17:13 +0000
Commit:     Dimitry Andric <d...@freebsd.org>
CommitDate: 2024-12-28 21:18:20 +0000

     Export additional __aeabi_ symbols from arm's libgcc_s
Some programs depend on these symbols, when they are compiled for armv6
     or armv7. Closes #1560 (slightly changed due to sorting of the symbols).
PR: 271087
     Reported by:    fuz
     Submitted by:   j...@mit.edu
     MFC after:      1 week
---
  lib/libgcc_s/arm/Symbol.map | 27 ++++++++++++++++++++++++++-
  1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/lib/libgcc_s/arm/Symbol.map b/lib/libgcc_s/arm/Symbol.map
index 92b54761d810..a426f823de5c 100644
--- a/lib/libgcc_s/arm/Symbol.map
+++ b/lib/libgcc_s/arm/Symbol.map
@@ -4,8 +4,33 @@
  GCC_3.5 {
        _Unwind_Complete;
        _Unwind_VRS_Get;
-       _Unwind_VRS_Set;
        _Unwind_VRS_Pop;
+       _Unwind_VRS_Set;
+       __aeabi_d2h;
+       __aeabi_d2lz;
+       __aeabi_d2ulz;
+       __aeabi_f2h;
+       __aeabi_f2lz;
+       __aeabi_f2ulz;
+       __aeabi_h2f;
+       __aeabi_idiv;
+       __aeabi_idiv0;
+       __aeabi_l2d;
+       __aeabi_l2f;
+       __aeabi_lasr;
+       __aeabi_lcmp;
+       __aeabi_ldivmod;
+       __aeabi_llsl;
+       __aeabi_llsr;
+       __aeabi_lmul;
+       __aeabi_ui2d;
+       __aeabi_ui2f;
+       __aeabi_uidiv;
+       __aeabi_uidivmod;
+       __aeabi_ul2d;
+       __aeabi_ul2f;
+       __aeabi_ulcmp;
+       __aeabi_uldivmod;
        __aeabi_unwind_cpp_pr0;
        __aeabi_unwind_cpp_pr1;
        __aeabi_unwind_cpp_pr2;

I think the aeabi_ functions with floating point arguments were not added correctly. By definition, they must be compiled with -mfloat-abi=softfp event if the rest of the library is compiled with hardfp abi.

It is also not clear why they are added to lib/libgcc_s/arm/Symbol.map and not to lib/libc/arm/aeabi/Symbol.map, where the other (some now duplicated) aeabi_ symbols are.

Also, the list of aeabi_ functions in is not complete, although the compiler_rt library contains them (__aeabi_f2d, __aeabi_f2iz...).

When I looked at it, I found another problem - the whole vfp suffix dance in https://cgit.freebsd.org/src/tree/lib/libcompiler_rt/Makefile.inc#n277 is pointless, all these functions have the same extension in their name. They are expected to be compiled (again with -mfloat-abi=softfp) together with the version without the suffix , and the rt linker will select the appropriate version depending on the VFP presence.

In addition, the makefile searches for resources in the wrong order,
contrib/llvm-project/compiler-rt/lib/builtins is searched before
contrib/llvm-project/compiler-rt/lib/builtins/<arch>, so for example a non-specific fp_mode is built, not an architecture-specific one.

What now? For me the most important question is in which map (and namespace) should the aeabi_ symbols be defined (without breaking the ABI for the user space).

Michal


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