[mips] Make TTypeEncoding indirect to allow .eh_frame to be read-only.

Summary:
Following on from r209907 which made personality encodings indirect, do the
same for TType encodings. This fixes the case where a try/catch block needs
to generate references to, for example, std::exception in the
.gcc_except_table.

Previous attempts at committing this broke the buildbots due to bugs in IAS.
These bugs have now been fixed so trying again.

Reviewers: petarj

Reviewed By: petarj

Subscribers: srhines, joerg, tberghammer, llvm-commits

Differential Revision: http://reviews.llvm.org/D9669

llvm-svn: 238863

diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index b6b72e6..ae3260d 100644 (file)
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -324,10 +324,16 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
   case Triple::mipsel:
   case Triple::mips64:
   case Triple::mips64el:
-    // 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.
+    // MIPS uses indirect pointer to refer personality functions and types, so
+    // that the eh_frame section can be read-only. DW.ref.personality will be
+    // generated for relocation.
     PersonalityEncoding = dwarf::DW_EH_PE_indirect;
+    // FIXME: The N64 ABI probably ought to use DW_EH_PE_sdata8 but we can't
+    //        identify N64 from just a triple.
+    TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+                    dwarf::DW_EH_PE_sdata4;
+    // We don't support PC-relative LSDA references in GAS so we use the default
+    // DW_EH_PE_absptr for those.
     break;
   case Triple::ppc64:
   case Triple::ppc64le:

diff --git a/llvm/test/CodeGen/Mips/ehframe-indirect.ll b/llvm/test/CodeGen/Mips/ehframe-indirect.ll
index f124881..dc06ef7 100644 (file)
--- a/llvm/test/CodeGen/Mips/ehframe-indirect.ll
+++ b/llvm/test/CodeGen/Mips/ehframe-indirect.ll
@@ -1,9 +1,11 @@
-; RUN: llc -mtriple=mipsel-linux-gnu < %s | FileCheck -check-prefix=ALL -check-prefix=O32 %s
-; RUN: llc -mtriple=mipsel-linux-android < %s | FileCheck -check-prefix=ALL -check-prefix=O32 %s
-; RUN: llc -mtriple=mips64el-linux-gnu -target-abi=n32 < %s | FileCheck -check-prefix=ALL -check-prefix=N32 %s
-; RUN: llc -mtriple=mips64el-linux-android -target-abi=n32 < %s | FileCheck -check-prefix=ALL -check-prefix=N32 %s
-; RUN: llc -mtriple=mips64el-linux-gnu < %s | FileCheck -check-prefix=ALL -check-prefix=N64 %s
-; RUN: llc -mtriple=mips64el-linux-android < %s | FileCheck -check-prefix=ALL -check-prefix=N64 %s
+; RUN: llc -mtriple=mipsel-linux-gnu < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=O32 %s
+; RUN: llc -mtriple=mipsel-linux-android < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=O32 %s
+; RUN: llc -mtriple=mips64el-linux-gnu -target-abi=n32 < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=N32 %s
+; RUN: llc -mtriple=mips64el-linux-android -target-abi=n32 < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=N32 %s
+; RUN: llc -mtriple=mips64el-linux-gnu < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=N64 %s
+; RUN: llc -mtriple=mips64el-linux-android < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=N64 %s
+
+@_ZTISt9exception = external constant i8*
 
 define i32 @main() {
 ; ALL: .cfi_startproc
@@ -16,7 +18,9 @@ entry:
 
 lpad:
   %0 = landingpad { i8*, i32 } personality i8*
-    bitcast (i32 (...)* @__gxx_personality_v0 to i8*) catch i8* null
+    bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+    catch i8* null
+    catch i8* bitcast (i8** @_ZTISt9exception to i8*)
   ret i32 0
 
 cont:
@@ -28,6 +32,14 @@ declare i32 @__gxx_personality_v0(...)
 
 declare void @foo()
 
+; ALL: GCC_except_table{{[0-9]+}}:
+; ALL: .byte 155 # @TType Encoding = indirect pcrel sdata4
+; ALL: $[[PC_LABEL:tmp[0-9]+]]:
+; ALL: .4byte  ($_ZTISt9exception.DW.stub)-($[[PC_LABEL]])
+; ALL: $_ZTISt9exception.DW.stub:
+; O32: .4byte _ZTISt9exception
+; N32: .4byte _ZTISt9exception
+; N64: .8byte _ZTISt9exception
 ; ALL: .hidden DW.ref.__gxx_personality_v0
 ; ALL: .weak DW.ref.__gxx_personality_v0
 ; ALL: .section .data.DW.ref.__gxx_personality_v0,"aGw",@progbits,DW.ref.__gxx_personality_v0,comdat