[StackMaps] Add a lightweight parser for stackmap version 1 sections.

The parser provides a convenient interface for reading llvm stackmap v1 sections
in object files.

This patch also includes a new option for llvm-readobj, '-stackmap', which uses
the parser to pretty-print stackmap sections for debugging/testing purposes.

llvm-svn: 240860

1 files changed, 80 insertions, 0 deletions

diff --git a/llvm/tools/llvm-readobj/StackMapPrinter.h b/llvm/tools/llvm-readobj/StackMapPrinter.h
new file mode 100644
index 00000000000..92645bcf917
--- /dev/null
+++ b/llvm/tools/llvm-readobj/StackMapPrinter.h
@@ -0,0 +1,80 @@
+//===-------- StackMapPrinter.h - Pretty-print stackmaps --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVM_READOBJ_STACKMAPPRINTER_H
+#define LLVM_TOOLS_LLVM_READOBJ_STACKMAPPRINTER_H
+
+#include "llvm/Object/StackMapParser.h"
+
+namespace llvm {
+
+// Pretty print a stackmap to the given ostream.
+template <typename OStreamT, typename StackMapParserT>
+void prettyPrintStackMap(OStreamT &OS, const StackMapParserT &SMP) {
+
+  OS << "LLVM StackMap Version: " << SMP.getVersion()
+     << "\nNum Functions: " << SMP.getNumFunctions();
+
+  // Functions:
+  for (const auto &F : SMP.functions())
+    OS << "\n  Function address: " << F.getFunctionAddress()
+       << ", stack size: " << F.getStackSize();
+
+  // Constants:
+  OS << "\nNum Constants: " << SMP.getNumConstants();
+  unsigned ConstantIndex = 0;
+  for (const auto &C : SMP.constants())
+    OS << "\n  #" << ++ConstantIndex << ": " << C.getValue();
+
+  // Records:
+  OS << "\nNum Records: " << SMP.getNumRecords();
+  for (const auto &R : SMP.records()) {
+    OS << "\n  Record ID: " << R.getID()
+       << ", instruction offset: " << R.getInstructionOffset()
+       << "\n    " << R.getNumLocations() << " locations:";
+
+    unsigned LocationIndex = 0;
+    for (const auto &Loc : R.locations()) {
+      OS << "\n      #" << ++LocationIndex << ": ";
+      switch (Loc.getKind()) {
+      case StackMapParserT::LocationKind::Register:
+        OS << "Register R#" << Loc.getDwarfRegNum();
+        break;
+      case StackMapParserT::LocationKind::Direct:
+        OS << "Direct R#" << Loc.getDwarfRegNum() << " + "
+           << Loc.getOffset();
+        break;
+      case StackMapParserT::LocationKind::Indirect:
+        OS << "Indirect [R#" << Loc.getDwarfRegNum() << " + "
+           << Loc.getOffset() << "]";
+        break;
+      case StackMapParserT::LocationKind::Constant:
+        OS << "Constant " << Loc.getSmallConstant();
+        break;
+      case StackMapParserT::LocationKind::ConstantIndex:
+        OS << "ConstantIndex #" << Loc.getConstantIndex() << " ("
+           << SMP.getConstant(Loc.getConstantIndex()).getValue() << ")";
+        break;
+      }
+    }
+
+    OS << "\n    " << R.getNumLiveOuts() << " live-outs: [ ";
+    for (const auto &LO : R.liveouts())
+      OS << "R#" << LO.getDwarfRegNum() << " ("
+         << LO.getSizeInBytes() << "-bytes) ";
+    OS << "]\n";
+  }
+
+ OS << "\n";
+
+}
+
+}
+
+#endif