Sketch out an CFG reconstruction mode for llvm-objdump.
- Not great yet, but it's a start.
- Requires an object file with a symbol table. (I really want to fix this, but it'll need a whole new algorithm)
- ELF and COFF won't work at the moment due to libObject shortcomings.
To try it out run
$ llvm-objdump -d --cfg foo.o
This will create a graphviz file for every symbol in the object file's text section containing a CFG.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135608 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-objdump/llvm-objdump.cpp b/tools/llvm-objdump/llvm-objdump.cpp
index 8f6e9df..21df7cc 100644
--- a/tools/llvm-objdump/llvm-objdump.cpp
+++ b/tools/llvm-objdump/llvm-objdump.cpp
@@ -13,6 +13,7 @@
//
//===----------------------------------------------------------------------===//
+#include "MCFunction.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/Triple.h"
@@ -21,6 +22,8 @@
#include "llvm/MC/MCDisassembler.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstPrinter.h"
+#include "llvm/MC/MCInstrDesc.h"
+#include "llvm/MC/MCInstrInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Format.h"
@@ -52,6 +55,10 @@
Disassembled("d", cl::desc("Alias for --disassemble"),
cl::aliasopt(Disassemble));
+ cl::opt<bool>
+ CFG("cfg", cl::desc("Create a CFG for every symbol in the object file and"
+ "write it to a graphviz file"));
+
cl::opt<std::string>
TripleName("triple", cl::desc("Target triple to disassemble for, "
"see -version for available targets"));
@@ -156,6 +163,7 @@
// GetTarget prints out stuff.
return;
}
+ const MCInstrInfo *InstrInfo = TheTarget->createMCInstrInfo();
outs() << '\n';
outs() << Filename
@@ -233,15 +241,14 @@
uint64_t End = si == se-1 ? SectSize : Symbols[si + 1].first - 1;
outs() << '\n' << Symbols[si].second << ":\n";
- for (Index = Start; Index < End; Index += Size) {
- MCInst Inst;
-
#ifndef NDEBUG
raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls();
#else
raw_ostream &DebugOut = nulls();
#endif
+ for (Index = Start; Index < End; Index += Size) {
+ MCInst Inst;
if (DisAsm->getInstruction(Inst, Size, memoryObject, Index, DebugOut)) {
uint64_t addr;
if (error(i->getAddress(addr))) break;
@@ -255,6 +262,36 @@
Size = 1; // skip illegible bytes
}
}
+
+ if (CFG) {
+ MCFunction f =
+ MCFunction::createFunctionFromMC(Symbols[si].second, DisAsm.get(),
+ memoryObject, Start, End, InstrInfo,
+ DebugOut);
+
+ // Start a new dot file.
+ std::string Error;
+ raw_fd_ostream Out((f.getName().str() + ".dot").c_str(), Error);
+
+ Out << "digraph " << f.getName() << " {\n";
+ Out << "graph [ rankdir = \"LR\" ];\n";
+ for (MCFunction::iterator i = f.begin(), e = f.end(); i != e; ++i) {
+ Out << '"' << (uintptr_t)&i->second << "\" [ label=\"<a>";
+ // Print instructions.
+ for (unsigned ii = 0, ie = i->second.getInsts().size(); ii != ie;
+ ++ii) {
+ IP->printInst(&i->second.getInsts()[ii].Inst, Out);
+ Out << '|';
+ }
+ Out << "<o>\" shape=\"record\" ];\n";
+
+ // Add edges.
+ for (MCBasicBlock::succ_iterator si = i->second.succ_begin(),
+ se = i->second.succ_end(); si != se; ++si)
+ Out << (uintptr_t)&i->second << ":o -> " << (uintptr_t)*si <<":a\n";
+ }
+ Out << "}\n";
+ }
}
}
}
@@ -271,6 +308,7 @@
llvm::InitializeAllTargets();
llvm::InitializeAllMCAsmInfos();
llvm::InitializeAllMCCodeGenInfos();
+ llvm::InitializeAllMCInstrInfos();
llvm::InitializeAllAsmPrinters();
llvm::InitializeAllAsmParsers();
llvm::InitializeAllDisassemblers();