1 files changed, 200 insertions, 0 deletions
diff --git a/contrib/llvm/lib/MC/MCDisassembler/MCExternalSymbolizer.cpp b/contrib/llvm/lib/MC/MCDisassembler/MCExternalSymbolizer.cpp
new file mode 100644
index 0000000..5fc2ca4
--- /dev/null
+++ b/contrib/llvm/lib/MC/MCDisassembler/MCExternalSymbolizer.cpp
@@ -0,0 +1,200 @@
+//===-- MCExternalSymbolizer.cpp - External symbolizer --------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCExternalSymbolizer.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cstring>
+
+using namespace llvm;
+
+namespace llvm {
+class Triple;
+}
+
+// This function tries to add a symbolic operand in place of the immediate
+// Value in the MCInst. The immediate Value has had any PC adjustment made by
+// the caller. If the instruction is a branch instruction then IsBranch is true,
+// else false. If the getOpInfo() function was set as part of the
+// setupForSymbolicDisassembly() call then that function is called to get any
+// symbolic information at the Address for this instruction. If that returns
+// non-zero then the symbolic information it returns is used to create an MCExpr
+// and that is added as an operand to the MCInst. If getOpInfo() returns zero
+// and IsBranch is true then a symbol look up for Value is done and if a symbol
+// is found an MCExpr is created with that, else an MCExpr with Value is
+// created. This function returns true if it adds an operand to the MCInst and
+// false otherwise.
+bool MCExternalSymbolizer::tryAddingSymbolicOperand(MCInst &MI,
+                                                    raw_ostream &cStream,
+                                                    int64_t Value,
+                                                    uint64_t Address,
+                                                    bool IsBranch,
+                                                    uint64_t Offset,
+                                                    uint64_t InstSize) {
+  struct LLVMOpInfo1 SymbolicOp;
+  std::memset(&SymbolicOp, '\0', sizeof(struct LLVMOpInfo1));
+  SymbolicOp.Value = Value;
+
+  if (!GetOpInfo ||
+      !GetOpInfo(DisInfo, Address, Offset, InstSize, 1, &SymbolicOp)) {
+    // Clear SymbolicOp.Value from above and also all other fields.
+    std::memset(&SymbolicOp, '\0', sizeof(struct LLVMOpInfo1));
+
+    // At this point, GetOpInfo() did not find any relocation information about
+    // this operand and we are left to use the SymbolLookUp() call back to guess
+    // if the Value is the address of a symbol.  In the case this is a branch
+    // that always makes sense to guess.  But in the case of an immediate it is
+    // a bit more questionable if it is an address of a symbol or some other
+    // reference.  So if the immediate Value comes from a width of 1 byte,
+    // InstSize, we will not guess it is an address of a symbol.  Because in
+    // object files assembled starting at address 0 this usually leads to
+    // incorrect symbolication.
+    if (!SymbolLookUp || (InstSize == 1 && !IsBranch))
+      return false;
+
+    uint64_t ReferenceType;
+    if (IsBranch)
+       ReferenceType = LLVMDisassembler_ReferenceType_In_Branch;
+    else
+       ReferenceType = LLVMDisassembler_ReferenceType_InOut_None;
+    const char *ReferenceName;
+    const char *Name = SymbolLookUp(DisInfo, Value, &ReferenceType, Address,
+                                    &ReferenceName);
+    if (Name) {
+      SymbolicOp.AddSymbol.Name = Name;
+      SymbolicOp.AddSymbol.Present = true;
+      // If Name is a C++ symbol name put the human readable name in a comment.
+      if(ReferenceType == LLVMDisassembler_ReferenceType_DeMangled_Name)
+        cStream << ReferenceName;
+    }
+    // For branches always create an MCExpr so it gets printed as hex address.
+    else if (IsBranch) {
+      SymbolicOp.Value = Value;
+    }
+    if(ReferenceType == LLVMDisassembler_ReferenceType_Out_SymbolStub)
+      cStream << "symbol stub for: " << ReferenceName;
+    else if(ReferenceType == LLVMDisassembler_ReferenceType_Out_Objc_Message)
+      cStream << "Objc message: " << ReferenceName;
+    if (!Name && !IsBranch)
+      return false;
+  }
+
+  const MCExpr *Add = nullptr;
+  if (SymbolicOp.AddSymbol.Present) {
+    if (SymbolicOp.AddSymbol.Name) {
+      StringRef Name(SymbolicOp.AddSymbol.Name);
+      MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
+      Add = MCSymbolRefExpr::create(Sym, Ctx);
+    } else {
+      Add = MCConstantExpr::create((int)SymbolicOp.AddSymbol.Value, Ctx);
+    }
+  }
+
+  const MCExpr *Sub = nullptr;
+  if (SymbolicOp.SubtractSymbol.Present) {
+      if (SymbolicOp.SubtractSymbol.Name) {
+      StringRef Name(SymbolicOp.SubtractSymbol.Name);
+      MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
+      Sub = MCSymbolRefExpr::create(Sym, Ctx);
+    } else {
+      Sub = MCConstantExpr::create((int)SymbolicOp.SubtractSymbol.Value, Ctx);
+    }
+  }
+
+  const MCExpr *Off = nullptr;
+  if (SymbolicOp.Value != 0)
+    Off = MCConstantExpr::create(SymbolicOp.Value, Ctx);
+
+  const MCExpr *Expr;
+  if (Sub) {
+    const MCExpr *LHS;
+    if (Add)
+      LHS = MCBinaryExpr::createSub(Add, Sub, Ctx);
+    else
+      LHS = MCUnaryExpr::createMinus(Sub, Ctx);
+    if (Off)
+      Expr = MCBinaryExpr::createAdd(LHS, Off, Ctx);
+    else
+      Expr = LHS;
+  } else if (Add) {
+    if (Off)
+      Expr = MCBinaryExpr::createAdd(Add, Off, Ctx);
+    else
+      Expr = Add;
+  } else {
+    if (Off)
+      Expr = Off;
+    else
+      Expr = MCConstantExpr::create(0, Ctx);
+  }
+
+  Expr = RelInfo->createExprForCAPIVariantKind(Expr, SymbolicOp.VariantKind);
+  if (!Expr)
+    return false;
+
+  MI.addOperand(MCOperand::createExpr(Expr));
+  return true;
+}
+
+// This function tries to add a comment as to what is being referenced by a load
+// instruction with the base register that is the Pc.  These can often be values
+// in a literal pool near the Address of the instruction. The Address of the
+// instruction and its immediate Value are used as a possible literal pool entry.
+// The SymbolLookUp call back will return the name of a symbol referenced by the
+// literal pool's entry if the referenced address is that of a symbol. Or it
+// will return a pointer to a literal 'C' string if the referenced address of
+// the literal pool's entry is an address into a section with C string literals.
+// Or if the reference is to an Objective-C data structure it will return a
+// specific reference type for it and a string.
+void MCExternalSymbolizer::tryAddingPcLoadReferenceComment(raw_ostream &cStream,
+                                                           int64_t Value,
+                                                           uint64_t Address) {
+  if (SymbolLookUp) {
+    uint64_t ReferenceType = LLVMDisassembler_ReferenceType_In_PCrel_Load;
+    const char *ReferenceName;
+    (void)SymbolLookUp(DisInfo, Value, &ReferenceType, Address, &ReferenceName);
+    if(ReferenceType == LLVMDisassembler_ReferenceType_Out_LitPool_SymAddr)
+      cStream << "literal pool symbol address: " << ReferenceName;
+    else if(ReferenceType ==
+            LLVMDisassembler_ReferenceType_Out_LitPool_CstrAddr) {
+      cStream << "literal pool for: \"";
+      cStream.write_escaped(ReferenceName);
+      cStream << "\"";
+    }
+    else if(ReferenceType ==
+            LLVMDisassembler_ReferenceType_Out_Objc_CFString_Ref)
+      cStream << "Objc cfstring ref: @\"" << ReferenceName << "\"";
+    else if(ReferenceType ==
+            LLVMDisassembler_ReferenceType_Out_Objc_Message)
+      cStream << "Objc message: " << ReferenceName;
+    else if(ReferenceType ==
+            LLVMDisassembler_ReferenceType_Out_Objc_Message_Ref)
+      cStream << "Objc message ref: " << ReferenceName;
+    else if(ReferenceType ==
+            LLVMDisassembler_ReferenceType_Out_Objc_Selector_Ref)
+      cStream << "Objc selector ref: " << ReferenceName;
+    else if(ReferenceType ==
+            LLVMDisassembler_ReferenceType_Out_Objc_Class_Ref)
+      cStream << "Objc class ref: " << ReferenceName;
+  }
+}
+
+namespace llvm {
+MCSymbolizer *createMCSymbolizer(const Triple &TT, LLVMOpInfoCallback GetOpInfo,
+                                 LLVMSymbolLookupCallback SymbolLookUp,
+                                 void *DisInfo, MCContext *Ctx,
+                                 std::unique_ptr<MCRelocationInfo> &&RelInfo) {
+  assert(Ctx && "No MCContext given for symbolic disassembly");
+
+  return new MCExternalSymbolizer(*Ctx, std::move(RelInfo), GetOpInfo,
+                                  SymbolLookUp, DisInfo);
+}
+}