commit 33fe63846fa747e61a1220f3298050106db6ae4e
author Martin Storsjö <martin@martin.st> Sat May 07 00:26:45 2022 +0300
committer Copybara-Service <copybara-worker@google.com> Mon Jun 06 13:31:02 2022 -0700
tree add31a8388ce554c22a29750345198a69f6565ef
parent 883e8899caa09c05c4a190e9a1c5110794bae21f

[libunwind] Fix SEH unwinding on ARM

Check `__SEH__` when checking if ARM EHABI should be implied,
similarly to 4a3722a2c3dff1fe885cc38bf43d3c095c9851e7 / D126866.

Fix a warning by using the right format specifier (PRIxPTR instead
of PRIx64), and add a double->float cast in a codepath that hasn't
been built so far.

This is enough to make SEH unwinding of itanium ABI exceptions on
ARM mostly work - one specific issue is fixed in a separate follow-up
patch.

Differential Revision: https://reviews.llvm.org/D126867

GitOrigin-RevId: 7c0e93cb89e6aa74881411213abf83faae7c58ee

include/__libunwind_config.h

diff --git a/include/__libunwind_config.h b/include/__libunwind_config.h
index e626567..5e9de90 100644
--- a/include/__libunwind_config.h
+++ b/include/__libunwind_config.h
@@ -12,7 +12,7 @@
 #define _LIBUNWIND_VERSION 15000
 
 #if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && \
-    !defined(__ARM_DWARF_EH__)
+    !defined(__ARM_DWARF_EH__) && !defined(__SEH__)
 #define _LIBUNWIND_ARM_EHABI
 #endif
 

include/libunwind.h

diff --git a/include/libunwind.h b/include/libunwind.h
index 3d8fd21..f878b46 100644
--- a/include/libunwind.h
+++ b/include/libunwind.h
@@ -81,7 +81,7 @@
 
 typedef int unw_regnum_t;
 typedef uintptr_t unw_word_t;
-#if defined(__arm__) && !defined(__ARM_DWARF_EH__)
+#if defined(__arm__) && !defined(__ARM_DWARF_EH__) && !defined(__SEH__)
 typedef uint64_t unw_fpreg_t;
 #else
 typedef double unw_fpreg_t;

src/Unwind-seh.cpp

diff --git a/src/Unwind-seh.cpp b/src/Unwind-seh.cpp
index f00bc47..64aaf0a 100644
--- a/src/Unwind-seh.cpp
+++ b/src/Unwind-seh.cpp
@@ -255,8 +255,8 @@
           (frameInfo.start_ip + offset > frameInfo.end_ip))
         functionName = ".anonymous.";
       _LIBUNWIND_TRACE_UNWINDING(
-          "unwind_phase2_forced(ex_ojb=%p): start_ip=0x%" PRIx64
-          ", func=%s, lsda=0x%" PRIx64 ", personality=0x%" PRIx64,
+          "unwind_phase2_forced(ex_ojb=%p): start_ip=0x%" PRIxPTR
+          ", func=%s, lsda=0x%" PRIxPTR ", personality=0x%" PRIxPTR,
           (void *)exception_object, frameInfo.start_ip, functionName,
           frameInfo.lsda, frameInfo.handler);
     }

src/UnwindCursor.hpp

diff --git a/src/UnwindCursor.hpp b/src/UnwindCursor.hpp
index 6e8fc45..dc334ed 100644
--- a/src/UnwindCursor.hpp
+++ b/src/UnwindCursor.hpp
@@ -863,7 +863,7 @@
       uint32_t w;
       float f;
     } d;
-    d.f = value;
+    d.f = (float)value;
     _msContext.S[regNum - UNW_ARM_S0] = d.w;
   }
   if (regNum >= UNW_ARM_D0 && regNum <= UNW_ARM_D31) {