[libunwind][MIPS] Support MIPS floating-point registers for hard-float ABIs.

Summary:
For MIPS ABIs with 64-bit floating point registers including newabi
and O32 with 64-bit floating point registers, just save and restore the
32 floating-point registers as doubles.

For O32 MIPS with 32-bit floating-point registers, save and restore the
individual floating-point registers as "plain" registers.  These registers
are encoded as floats rather than doubles, but the DWARF unwinder
assumes that floating-point registers are stored as doubles when reading
them from memory (via AddressSpace::getDouble()).  Treating the
registers as "normal" registers instead causes the DWARF unwinder to
fetch them from memory as a 32-bit register.  This does mean that for
O32 with 32-bit floating-point registers unw_get_fpreg() and
unw_set_fpreg() do not work.  One would have to use unw_get_reg()
and unw_set_reg() instead.  However, DWARF unwinding works
correctly as the DWARF CFI emits records for individual 32-bit
floating-point registers even when they are treated as doubles stored
in paired registers.  If the lack of unw_get/set_fpreg() becomes a pressing
need in the future for O32 MIPS we could add in special handling to
make it work.

Reviewers: sdardis, compnerd

Reviewed By: sdardis

Differential Revision: https://reviews.llvm.org/D41968


git-svn-id: https://llvm.org/svn/llvm-project/libunwind/trunk@332414 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 89 insertions, 3 deletions

diff --git a/src/UnwindRegistersSave.S b/src/UnwindRegistersSave.S
index 1b6cff8..ac925d9 100644
--- a/src/UnwindRegistersSave.S
+++ b/src/UnwindRegistersSave.S
@@ -116,8 +116,7 @@ DEFINE_LIBUNWIND_FUNCTION(unw_getcontext)
   xorl  %eax, %eax    # return UNW_ESUCCESS
   ret
 
-#elif defined(__mips__) && defined(_ABIO32) && _MIPS_SIM == _ABIO32 &&         \
-    defined(__mips_soft_float)
+#elif defined(__mips__) && defined(_ABIO32) && _MIPS_SIM == _ABIO32
 
 #
 # extern int unw_getcontext(unw_context_t* thread_state)
@@ -168,12 +167,65 @@ DEFINE_LIBUNWIND_FUNCTION(unw_getcontext)
   sw    $8,  (4 * 33)($4)
   mflo  $8
   sw    $8,  (4 * 34)($4)
+#ifdef __mips_hard_float
+#if __mips_fpr == 32
+  sdc1  $f0, (4 * 36 + 8 * 0)($4)
+  sdc1  $f2, (4 * 36 + 8 * 2)($4)
+  sdc1  $f4, (4 * 36 + 8 * 4)($4)
+  sdc1  $f6, (4 * 36 + 8 * 6)($4)
+  sdc1  $f8, (4 * 36 + 8 * 8)($4)
+  sdc1  $f10, (4 * 36 + 8 * 10)($4)
+  sdc1  $f12, (4 * 36 + 8 * 12)($4)
+  sdc1  $f14, (4 * 36 + 8 * 14)($4)
+  sdc1  $f16, (4 * 36 + 8 * 16)($4)
+  sdc1  $f18, (4 * 36 + 8 * 18)($4)
+  sdc1  $f20, (4 * 36 + 8 * 20)($4)
+  sdc1  $f22, (4 * 36 + 8 * 22)($4)
+  sdc1  $f24, (4 * 36 + 8 * 24)($4)
+  sdc1  $f26, (4 * 36 + 8 * 26)($4)
+  sdc1  $f28, (4 * 36 + 8 * 28)($4)
+  sdc1  $f30, (4 * 36 + 8 * 30)($4)
+#else
+  sdc1  $f0, (4 * 36 + 8 * 0)($4)
+  sdc1  $f1, (4 * 36 + 8 * 1)($4)
+  sdc1  $f2, (4 * 36 + 8 * 2)($4)
+  sdc1  $f3, (4 * 36 + 8 * 3)($4)
+  sdc1  $f4, (4 * 36 + 8 * 4)($4)
+  sdc1  $f5, (4 * 36 + 8 * 5)($4)
+  sdc1  $f6, (4 * 36 + 8 * 6)($4)
+  sdc1  $f7, (4 * 36 + 8 * 7)($4)
+  sdc1  $f8, (4 * 36 + 8 * 8)($4)
+  sdc1  $f9, (4 * 36 + 8 * 9)($4)
+  sdc1  $f10, (4 * 36 + 8 * 10)($4)
+  sdc1  $f11, (4 * 36 + 8 * 11)($4)
+  sdc1  $f12, (4 * 36 + 8 * 12)($4)
+  sdc1  $f13, (4 * 36 + 8 * 13)($4)
+  sdc1  $f14, (4 * 36 + 8 * 14)($4)
+  sdc1  $f15, (4 * 36 + 8 * 15)($4)
+  sdc1  $f16, (4 * 36 + 8 * 16)($4)
+  sdc1  $f17, (4 * 36 + 8 * 17)($4)
+  sdc1  $f18, (4 * 36 + 8 * 18)($4)
+  sdc1  $f19, (4 * 36 + 8 * 19)($4)
+  sdc1  $f20, (4 * 36 + 8 * 20)($4)
+  sdc1  $f21, (4 * 36 + 8 * 21)($4)
+  sdc1  $f22, (4 * 36 + 8 * 22)($4)
+  sdc1  $f23, (4 * 36 + 8 * 23)($4)
+  sdc1  $f24, (4 * 36 + 8 * 24)($4)
+  sdc1  $f25, (4 * 36 + 8 * 25)($4)
+  sdc1  $f26, (4 * 36 + 8 * 26)($4)
+  sdc1  $f27, (4 * 36 + 8 * 27)($4)
+  sdc1  $f28, (4 * 36 + 8 * 28)($4)
+  sdc1  $f29, (4 * 36 + 8 * 29)($4)
+  sdc1  $f30, (4 * 36 + 8 * 30)($4)
+  sdc1  $f31, (4 * 36 + 8 * 31)($4)
+#endif
+#endif
   jr	$31
   # return UNW_ESUCCESS
   or    $2, $0, $0
   .set pop
 
-#elif defined(__mips64) && defined(__mips_soft_float)
+#elif defined(__mips64)
 
 #
 # extern int unw_getcontext(unw_context_t* thread_state)
@@ -224,6 +276,40 @@ DEFINE_LIBUNWIND_FUNCTION(unw_getcontext)
   sd    $8,  (8 * 33)($4)
   mflo  $8
   sd    $8,  (8 * 34)($4)
+#ifdef __mips_hard_float
+  sdc1  $f0, (8 * 35)($4)
+  sdc1  $f1, (8 * 36)($4)
+  sdc1  $f2, (8 * 37)($4)
+  sdc1  $f3, (8 * 38)($4)
+  sdc1  $f4, (8 * 39)($4)
+  sdc1  $f5, (8 * 40)($4)
+  sdc1  $f6, (8 * 41)($4)
+  sdc1  $f7, (8 * 42)($4)
+  sdc1  $f8, (8 * 43)($4)
+  sdc1  $f9, (8 * 44)($4)
+  sdc1  $f10, (8 * 45)($4)
+  sdc1  $f11, (8 * 46)($4)
+  sdc1  $f12, (8 * 47)($4)
+  sdc1  $f13, (8 * 48)($4)
+  sdc1  $f14, (8 * 49)($4)
+  sdc1  $f15, (8 * 50)($4)
+  sdc1  $f16, (8 * 51)($4)
+  sdc1  $f17, (8 * 52)($4)
+  sdc1  $f18, (8 * 53)($4)
+  sdc1  $f19, (8 * 54)($4)
+  sdc1  $f20, (8 * 55)($4)
+  sdc1  $f21, (8 * 56)($4)
+  sdc1  $f22, (8 * 57)($4)
+  sdc1  $f23, (8 * 58)($4)
+  sdc1  $f24, (8 * 59)($4)
+  sdc1  $f25, (8 * 60)($4)
+  sdc1  $f26, (8 * 61)($4)
+  sdc1  $f27, (8 * 62)($4)
+  sdc1  $f28, (8 * 63)($4)
+  sdc1  $f29, (8 * 64)($4)
+  sdc1  $f30, (8 * 65)($4)
+  sdc1  $f31, (8 * 66)($4)
+#endif
   jr	$31
   # return UNW_ESUCCESS
   or    $2, $0, $0