[PATCH] D147372: [libunwind][LoongArch] Restore $r1 before $r4 in `jumpto`

[Lu Weining via Phabricator via llvm-commits]

SixWeining created this revision.
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$r1 should be restored before $r4, otherwise the baseaddress ($r4) would
be destroyed. See file `UnwindRegistersSave.S` for reference.

This also makes libcxx and libcxxabi regtest pass for the `-DLIBCXXABI_USE_LLVM_UNWINDER=ON` build.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D147372

Files:
  libunwind/src/UnwindRegistersRestore.S
  libunwind/test/unw_resume.pass.cpp


Index: libunwind/test/unw_resume.pass.cpp
===================================================================
--- libunwind/test/unw_resume.pass.cpp
+++ libunwind/test/unw_resume.pass.cpp
@@ -10,11 +10,6 @@
 // Ensure that unw_resume() resumes execution at the stack frame identified by
 // cursor.
 
-// FIXME: The return address register($ra/$r1) is restored with a destroyed base
-// address register($a0/$r4) in the assembly file `UnwindRegistersRestore.S` on
-// LoongArch. And we will fix this issue in the next commit.
-// XFAIL: target={{loongarch64-.+}}
-
 #include <libunwind.h>
 
 void test_unw_resume() {
Index: libunwind/src/UnwindRegistersRestore.S
===================================================================
--- libunwind/src/UnwindRegistersRestore.S
+++ libunwind/src/UnwindRegistersRestore.S
@@ -1221,8 +1221,8 @@
     ld.d $r\i, $a0, (8 * \i)
   .endr
 
-  ld.d    $r4,  $a0, (8 * 4)   // restore $a0 last
   ld.d    $r1,  $a0, (8 * 32)  // load new pc into $ra
+  ld.d    $r4,  $a0, (8 * 4)   // restore $a0 last
 
   jr      $ra
 


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