[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
llvm-svn: 332414
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: c3f240f7dc0387a6efabb75ee86cd5b453e0b196
diff --git a/src/libunwind.cpp b/src/libunwind.cpp
index c7318fb..a3bcfb5 100644
--- a/src/libunwind.cpp
+++ b/src/libunwind.cpp
@@ -61,10 +61,9 @@
# define REGISTER_KIND Registers_arm
#elif defined(__or1k__)
# define REGISTER_KIND Registers_or1k
-#elif defined(__mips__) && defined(_ABIO32) && _MIPS_SIM == _ABIO32 && \
- defined(__mips_soft_float)
+#elif defined(__mips__) && defined(_ABIO32) && _MIPS_SIM == _ABIO32
# define REGISTER_KIND Registers_mips_o32
-#elif defined(__mips64) && defined(__mips_soft_float)
+#elif defined(__mips64)
# define REGISTER_KIND Registers_mips_newabi
#elif defined(__mips__)
# warning The MIPS architecture is not supported with this ABI and environment!