commit 66d2c269dc153c36cb35898082a38eb47bbb4ce0
author Francis Visoiu Mistrih <francisvm@yahoo.com> Thu Nov 02 12:00:58 2017 +0000
committer Francis Visoiu Mistrih <francisvm@yahoo.com> Thu Nov 02 12:00:58 2017 +0000
tree 80a1abeec5edff352463a3b5c6c79ae83d75968f
parent e73b85d1abfe7363164c5a7e5f58c1ceaeeb62f9

[AsmPrinterDwarf] Add support for .cfi_restore directive

As of today we only use .cfi_offset to specify the offset of a CSR, but
we never use .cfi_restore when the CSR is restored.

If we want to perform a more advanced type of shrink-wrapping, we need
to use .cfi_restore in order to switch the CFI state between blocks.

This patch only aims at adding support for the directive.

Differential Revision: https://reviews.llvm.org/D36114

llvm-svn: 317199

llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
index 7b3fe05..3f144c0 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
@@ -219,6 +219,9 @@
   case MCCFIInstruction::OpEscape:
     OutStreamer->EmitCFIEscape(Inst.getValues());
     break;
+  case MCCFIInstruction::OpRestore:
+    OutStreamer->EmitCFIRestore(Inst.getRegister());
+    break;
   }
 }
 

llvm/lib/CodeGen/MIRParser/MILexer.cpp

diff --git a/llvm/lib/CodeGen/MIRParser/MILexer.cpp b/llvm/lib/CodeGen/MIRParser/MILexer.cpp
index 0ba346c..d23df9c 100644
--- a/llvm/lib/CodeGen/MIRParser/MILexer.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MILexer.cpp
@@ -216,6 +216,7 @@
       .Case("def_cfa_register", MIToken::kw_cfi_def_cfa_register)
       .Case("def_cfa_offset", MIToken::kw_cfi_def_cfa_offset)
       .Case("def_cfa", MIToken::kw_cfi_def_cfa)
+      .Case("restore", MIToken::kw_cfi_restore)
       .Case("blockaddress", MIToken::kw_blockaddress)
       .Case("intrinsic", MIToken::kw_intrinsic)
       .Case("target-index", MIToken::kw_target_index)

llvm/lib/CodeGen/MIRParser/MILexer.h

diff --git a/llvm/lib/CodeGen/MIRParser/MILexer.h b/llvm/lib/CodeGen/MIRParser/MILexer.h
index 886916b..6894fe8 100644
--- a/llvm/lib/CodeGen/MIRParser/MILexer.h
+++ b/llvm/lib/CodeGen/MIRParser/MILexer.h
@@ -68,6 +68,7 @@
     kw_cfi_def_cfa_register,
     kw_cfi_def_cfa_offset,
     kw_cfi_def_cfa,
+    kw_cfi_restore,
     kw_blockaddress,
     kw_intrinsic,
     kw_target_index,

llvm/lib/CodeGen/MIRParser/MIParser.cpp

diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index 1000eb0..9c8743a 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -1634,6 +1634,12 @@
     CFIIndex =
         MF.addFrameInst(MCCFIInstruction::createDefCfa(nullptr, Reg, -Offset));
     break;
+  case MIToken::kw_cfi_restore:
+    if (parseCFIRegister(Reg))
+      return true;
+    CFIIndex = MF.addFrameInst(MCCFIInstruction::createRestore(nullptr, Reg));
+    break;
+
   default:
     // TODO: Parse the other CFI operands.
     llvm_unreachable("The current token should be a cfi operand");
@@ -1912,6 +1918,7 @@
   case MIToken::kw_cfi_def_cfa_register:
   case MIToken::kw_cfi_def_cfa_offset:
   case MIToken::kw_cfi_def_cfa:
+  case MIToken::kw_cfi_restore:
     return parseCFIOperand(Dest);
   case MIToken::kw_blockaddress:
     return parseBlockAddressOperand(Dest);

llvm/lib/CodeGen/MIRPrinter.cpp

diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index f8da8d3..aae4858 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -1243,6 +1243,12 @@
     printCFIRegister(CFI.getRegister(), OS, TRI);
     OS << ", " << CFI.getOffset();
     break;
+  case MCCFIInstruction::OpRestore:
+    OS << "restore ";
+    if (CFI.getLabel())
+      OS << "<mcsymbol> ";
+    printCFIRegister(CFI.getRegister(), OS, TRI);
+    break;
   default:
     // TODO: Print the other CFI Operations.
     OS << "<unserializable cfi operation>";