[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, 31 insertions, 1 deletions

diff --git a/llvm/tools/llvm-readobj/COFFDumper.cpp b/llvm/tools/llvm-readobj/COFFDumper.cpp
index 4a1d5da30e6..0041c7ef6a9 100644
--- a/llvm/tools/llvm-readobj/COFFDumper.cpp
+++ b/llvm/tools/llvm-readobj/COFFDumper.cpp
@@ -16,6 +16,7 @@
 #include "ARMWinEHPrinter.h"
 #include "Error.h"
 #include "ObjDumper.h"
+#include "StackMapPrinter.h"
 #include "StreamWriter.h"
 #include "Win64EHDumper.h"
 #include "llvm/ADT/DenseMap.h"
@@ -60,7 +61,7 @@ public:
   void printCOFFExports() override;
   void printCOFFDirectives() override;
   void printCOFFBaseReloc() override;
-
+  void printStackMap() const override;
 private:
   void printSymbol(const SymbolRef &Sym);
   void printRelocation(const SectionRef &Section, const RelocationRef &Reloc);
@@ -1140,3 +1141,32 @@ void COFFDumper::printCOFFBaseReloc() {
     W.printHex("Address", RVA);
   }
 }
+
+void COFFDumper::printStackMap() const {
+  object::SectionRef StackMapSection;
+  for (auto Sec : Obj->sections()) {
+    StringRef Name;
+    Sec.getName(Name);
+    if (Name == ".llvm_stackmaps") {
+      StackMapSection = Sec;
+      break;
+    }
+  }
+
+  if (StackMapSection == object::SectionRef())
+    return;
+
+  StringRef StackMapContents;
+  StackMapSection.getContents(StackMapContents);
+  ArrayRef<uint8_t> StackMapContentsArray(
+      reinterpret_cast<const uint8_t*>(StackMapContents.data()),
+      StackMapContents.size());
+
+  if (Obj->isLittleEndian())
+    prettyPrintStackMap(
+                      llvm::outs(),
+                      StackMapV1Parser<support::little>(StackMapContentsArray));
+  else
+    prettyPrintStackMap(llvm::outs(),
+                        StackMapV1Parser<support::big>(StackMapContentsArray));
+}