[PPC][BOLT] Add minimal PowerPC MCSymbolizer.

Introduce PPCMCSymbolizer.
This initial version supports resolving relocations by printing symbolic
names and attaching them to instructions. It enables BOLT to disassemble
simple PowerPC binaries (e.g., Hello World) with basic symbolic operands.

Author: kostasalv

bolt/lib/Target/PowerPC/CMakeLists.txt

@@ -17,6 +17,7 @@ endif()
 
 add_llvm_library(LLVMBOLTTargetPowerPC
   PPCMCPlusBuilder.cpp
+  PPCMCSymbolizer.cpp
 
   NO_EXPORT
   DISABLE_LLVM_LINK_LLVM_DYLIB

bolt/lib/Target/PowerPC/PPCMCSymbolizer.cpp

@@ -0,0 +1,45 @@
+//===- bolt/Target/PPC/PPCMCSymbolizer.cpp ----------------------*- C++ -*-===//
+//
+// Minimal PowerPC Symbolizer for BOLT "Hello World" Programs
+//
+//===----------------------------------------------------------------------===//
+
+#include "PPCMCSymbolizer.h"
+#include "bolt/Core/BinaryFunction.h"
+#include "bolt/Core/Relocation.h"
+#include "llvm/MC/MCInst.h"
+
+using namespace llvm;
+using namespace bolt;
+
+PPCMCSymbolizer::~PPCMCSymbolizer() = default;
+
+bool PPCMCSymbolizer::tryAddingSymbolicOperand(
+    MCInst &Inst, raw_ostream &CStream, int64_t Value, uint64_t Address,
+    bool IsBranch, uint64_t Offset, uint64_t OpSize, uint64_t InstSize) {
+  // 1) Normalize to function-relative offset
+  BinaryContext &BC = Function.getBinaryContext();
+  MCContext *Ctx = BC.Ctx.get();
+  const uint64_t InstOffset = Address - Function.getAddress();
+
+  // 2) Find relocation at "instruction start + immediate offset"
+  const Relocation *Rel = Function.getRelocationAt(InstOffset + Offset);
+  if (!Rel)
+    return false;
+
+  // 3) Build MCExpr = Symbol [+ Addend] and attach as a real operand
+  const MCSymbol *Sym = Rel->Symbol; // prefer the pointer, not a name string
+  const MCExpr *Expr = MCSymbolRefExpr::create(Sym, *Ctx);
+  if (Rel->Addend)
+    Expr = MCBinaryExpr::createAdd(
+        Expr, MCConstantExpr::create(Rel->Addend, *Ctx), *Ctx);
+
+  Inst.addOperand(MCOperand::createExpr(Expr));
+  return true;
+}
+
+void PPCMCSymbolizer::tryAddingPcLoadReferenceComment(raw_ostream &CStream,
+                                                      int64_t Value,
+                                                      uint64_t Address) {
+  // For "Hello World": no special PC-relative loads, leave empty for now
+}

bolt/lib/Target/PowerPC/PPCMCSymbolizer.h

@@ -0,0 +1,42 @@
+//===- bolt/Target/PPC/PPCMCSymbolizer.h ------------------------*- C++ -*-===//
+//
+// Minimal PowerPC Symbolizer for BOLT "Hello World" Programs
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef BOLT_TARGET_PPC_PPCMCSYMBOLIZER_H
+#define BOLT_TARGET_PPC_PPCMCSYMBOLIZER_H
+
+#include "bolt/Core/BinaryFunction.h"
+#include "llvm/MC/MCDisassembler/MCSymbolizer.h"
+
+namespace llvm {
+namespace bolt {
+
+class PPCMCSymbolizer : public MCSymbolizer {
+protected:
+  BinaryFunction &Function;
+
+public:
+  PPCMCSymbolizer(BinaryFunction &Function)
+      : MCSymbolizer(*Function.getBinaryContext().Ctx, nullptr),
+        Function(Function) {}
+
+  PPCMCSymbolizer(const PPCMCSymbolizer &) = delete;
+  PPCMCSymbolizer &operator=(const PPCMCSymbolizer &) = delete;
+  virtual ~PPCMCSymbolizer();
+
+  /// Minimal: Try to add a symbolic operand if there is a matching relocation
+  bool tryAddingSymbolicOperand(MCInst &Inst, raw_ostream &CStream,
+                                int64_t Value, uint64_t Address, bool IsBranch,
+                                uint64_t Offset, uint64_t OpSize,
+                                uint64_t InstSize) override;
+
+  void tryAddingPcLoadReferenceComment(raw_ostream &CStream, int64_t Value,
+                                       uint64_t Address) override;
+};
+
+} // namespace bolt
+} // namespace llvm
+
+#endif