From: Logan Chien <tzuhsiang.chien@gmail.com>
Date: Fri, 30 May 2014 16:48:56 +0000 (+0000)
Subject: Fix MIPS exception personality encoding.
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=731d23ed42db0f876f0c9b2a3985637ef4ec8384;p=oota-llvm.git

Fix MIPS exception personality encoding.

For MIPS, we have to encode the personality routine with
an indirect pointer to absptr; otherwise, some link warning
warning will be raised, and the program might crash in some
early MIPS Android device.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209907 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
index 30312ac2e28..b5e95cb2626 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
@@ -59,7 +59,7 @@ void DwarfCFIException::endModule() {
 
   unsigned PerEncoding = TLOF.getPersonalityEncoding();
 
-  if ((PerEncoding & 0x70) != dwarf::DW_EH_PE_pcrel)
+  if ((PerEncoding & 0x80) != dwarf::DW_EH_PE_indirect)
     return;
 
   // Emit references to all used personality functions
diff --git a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index dda22599d25..d3494258151 100644
--- a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -48,16 +48,12 @@ MCSymbol *TargetLoweringObjectFileELF::getCFIPersonalitySymbol(
     const GlobalValue *GV, Mangler &Mang, const TargetMachine &TM,
     MachineModuleInfo *MMI) const {
   unsigned Encoding = getPersonalityEncoding();
-  switch (Encoding & 0x70) {
-  default:
-    report_fatal_error("We do not support this DWARF encoding yet!");
-  case dwarf::DW_EH_PE_absptr:
-    return TM.getSymbol(GV, Mang);
-  case dwarf::DW_EH_PE_pcrel: {
+  if ((Encoding & 0x80) == dwarf::DW_EH_PE_indirect)
     return getContext().GetOrCreateSymbol(StringRef("DW.ref.") +
                                           TM.getSymbol(GV, Mang)->getName());
-  }
-  }
+  if ((Encoding & 0x70) == dwarf::DW_EH_PE_absptr)
+    return TM.getSymbol(GV, Mang);
+  report_fatal_error("We do not support this DWARF encoding yet!");
 }
 
 void TargetLoweringObjectFileELF::emitPersonalityValue(MCStreamer &Streamer,
diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index 9d413afe5db..2a9bf6ade90 100644
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -321,6 +321,13 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
       TTypeEncoding = dwarf::DW_EH_PE_absptr;
     }
     break;
+  case Triple::mips:
+  case Triple::mipsel:
+    // MIPS uses indirect pointer to refer personality functions, so that the
+    // eh_frame section can be read-only.  DW.ref.personality will be generated
+    // for relocation.
+    PersonalityEncoding = dwarf::DW_EH_PE_indirect;
+    break;
   case Triple::ppc64:
   case Triple::ppc64le:
     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
diff --git a/test/CodeGen/Mips/ehframe-indirect.ll b/test/CodeGen/Mips/ehframe-indirect.ll
new file mode 100644
index 00000000000..e78497a9521
--- /dev/null
+++ b/test/CodeGen/Mips/ehframe-indirect.ll
@@ -0,0 +1,34 @@
+; RUN: llc -mtriple=mipsel-linux-gnu < %s | FileCheck %s
+; RUN: llc -mtriple=mipsel-linux-android < %s | FileCheck %s
+
+define i32 @main() {
+; CHECK: .cfi_startproc
+; CHECK: .cfi_personality 128, DW.ref.__gxx_personality_v0
+
+entry:
+  invoke void @foo() to label %cont unwind label %lpad
+; CHECK: foo
+; CHECK: jalr
+
+lpad:
+  %0 = landingpad { i8*, i32 } personality i8*
+    bitcast (i32 (...)* @__gxx_personality_v0 to i8*) catch i8* null
+  ret i32 0
+
+cont:
+  ret i32 0
+}
+; CHECK: .cfi_endproc
+
+declare i32 @__gxx_personality_v0(...)
+
+declare void @foo()
+
+; CHECK: .hidden DW.ref.__gxx_personality_v0
+; CHECK: .weak DW.ref.__gxx_personality_v0
+; CHECK: .section .data.DW.ref.__gxx_personality_v0,"aGw",@progbits,DW.ref.__gxx_personality_v0,comdat
+; CHECK: .align 2
+; CHECK: .type DW.ref.__gxx_personality_v0,@object
+; CHECK: .size DW.ref.__gxx_personality_v0, 4
+; CHECK: DW.ref.__gxx_personality_v0:
+; CHECK: .4byte __gxx_personality_v0