Make PrologEpilogInserter save/restore all callee saved registers

in functions which call __builtin_unwind_init()

__builtin_unwind_init() is an undocumented gcc intrinsic which has this effect,
and is used in libgcc_eh.

Goes part of the way toward fixing PR8541.

llvm-svn: 183984

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/PrologEpilogInserter.cpp b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
index 4b301d84ca4..9f2cba2195f 100644
--- a/llvm/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
@@ -29,6 +29,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/RegisterScavenging.h"
 #include "llvm/IR/InlineAsm.h"
@@ -227,7 +228,8 @@ void PEI::calculateCalleeSavedRegisters(MachineFunction &F) {
   std::vector<CalleeSavedInfo> CSI;
   for (unsigned i = 0; CSRegs[i]; ++i) {
     unsigned Reg = CSRegs[i];
-    if (F.getRegInfo().isPhysRegUsed(Reg)) {
+    // Functions which call __builtin_unwind_init get all their registers saved.
+    if (F.getRegInfo().isPhysRegUsed(Reg) || F.getMMI().callsUnwindInit()) {
       // If the reg is modified, save it!
       CSI.push_back(CalleeSavedInfo(Reg));
     }