[DebugInfo] Introduce DW_OP_LLVM_convert

Introduce a DW_OP_LLVM_convert Dwarf expression pseudo op that allows
for a convenient way to perform type conversions on the Dwarf expression
stack. As an additional bonus it paves the way for using other Dwarf
v5 ops that need to reference a base_type.

The new DW_OP_LLVM_convert is used from lib/Transforms/Utils/Local.cpp
to perform sext/zext on debug values but mainly the patch is about
preparing terrain for adding other Dwarf v5 ops that need to reference a
base_type.

For Dwarf v5 the op maps to DW_OP_convert and for earlier versions a
complex shift & mask pattern is generated to emulate sext/zext.

This is a recommit of r356442 with trivial fixes for the failing tests.

Differential Revision: https://reviews.llvm.org/D56587

llvm-svn: 356451

1 files changed, 5 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/ByteStreamer.h b/llvm/lib/CodeGen/AsmPrinter/ByteStreamer.h
index 7a2902d6807..db2ff458eb2 100644
--- a/llvm/lib/CodeGen/AsmPrinter/ByteStreamer.h
+++ b/llvm/lib/CodeGen/AsmPrinter/ByteStreamer.h
@@ -31,7 +31,7 @@ class ByteStreamer {
   // For now we're just handling the calls we need for dwarf emission/hashing.
   virtual void EmitInt8(uint8_t Byte, const Twine &Comment = "") = 0;
   virtual void EmitSLEB128(uint64_t DWord, const Twine &Comment = "") = 0;
-  virtual void EmitULEB128(uint64_t DWord, const Twine &Comment = "") = 0;
+  virtual void EmitULEB128(uint64_t DWord, const Twine &Comment = "", unsigned PadTo = 0) = 0;
 };
 
 class APByteStreamer final : public ByteStreamer {
@@ -48,7 +48,7 @@ public:
     AP.OutStreamer->AddComment(Comment);
     AP.EmitSLEB128(DWord);
   }
-  void EmitULEB128(uint64_t DWord, const Twine &Comment) override {
+  void EmitULEB128(uint64_t DWord, const Twine &Comment, unsigned PadTo) override {
     AP.OutStreamer->AddComment(Comment);
     AP.EmitULEB128(DWord);
   }
@@ -65,7 +65,7 @@ class HashingByteStreamer final : public ByteStreamer {
   void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
     Hash.addSLEB128(DWord);
   }
-  void EmitULEB128(uint64_t DWord, const Twine &Comment) override {
+  void EmitULEB128(uint64_t DWord, const Twine &Comment, unsigned PadTo) override {
     Hash.addULEB128(DWord);
   }
 };
@@ -102,9 +102,9 @@ public:
 
     }
   }
-  void EmitULEB128(uint64_t DWord, const Twine &Comment) override {
+  void EmitULEB128(uint64_t DWord, const Twine &Comment, unsigned PadTo) override {
     raw_svector_ostream OSE(Buffer);
-    unsigned Length = encodeULEB128(DWord, OSE);
+    unsigned Length = encodeULEB128(DWord, OSE, PadTo);
     if (GenerateComments) {
       Comments.push_back(Comment.str());
       // Add some empty comments to keep the Buffer and Comments vectors aligned