[PATCH] D50204: [llvm-objdump] Label calls to the PLT

Joel Galenson via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Thu Aug 9 08:32:01 PDT 2018


jgalenson updated this revision to Diff 159933.
jgalenson added a comment.

Added newline to end of tests.


https://reviews.llvm.org/D50204

Files:
  test/tools/llvm-objdump/AArch64/Inputs/simple-inheritance.elf-aarch64
  test/tools/llvm-objdump/AArch64/plt.test
  test/tools/llvm-objdump/X86/plt.test
  tools/llvm-objdump/llvm-objdump.cpp


Index: tools/llvm-objdump/llvm-objdump.cpp
===================================================================
--- tools/llvm-objdump/llvm-objdump.cpp
+++ tools/llvm-objdump/llvm-objdump.cpp
@@ -56,6 +56,7 @@
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/StringSaver.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/raw_ostream.h"
@@ -1236,6 +1237,34 @@
     llvm_unreachable("Unsupported binary format");
 }
 
+static void addPltEntries(const ObjectFile *Obj,
+                          std::map<SectionRef, SectionSymbolsTy> &AllSymbols,
+                          StringSaver &Saver) {
+  const SectionRef *Plt =
+      &*find_if(Obj->sections(), [&](const SectionRef &Section) {
+          StringRef Str;
+          return !Section.getName(Str) && Str == ".plt";
+        });
+  if (!Plt)
+    return;
+  if (auto *ElfObj = dyn_cast<ELFObjectFileBase>(Obj)) {
+    for (auto PltEntry : ElfObj->getPltAddresses()) {
+      SymbolRef Symbol(PltEntry.first, ElfObj);
+
+      uint8_t SymbolType = getElfSymbolType(Obj, Symbol);
+
+      Expected<StringRef> NameOrErr = Symbol.getName();
+      if (!NameOrErr)
+        report_error(Obj->getFileName(), NameOrErr.takeError());
+      if (NameOrErr->empty())
+        continue;
+      StringRef Name = Saver.save((*NameOrErr + "@plt").str());
+
+      AllSymbols[*Plt].emplace_back(PltEntry.second, Name, SymbolType);
+    }
+  }
+}
+
 static void DisassembleObject(const ObjectFile *Obj, bool InlineRelocs) {
   if (StartAddress > StopAddress)
     error("Start address should be less than stop address");
@@ -1343,6 +1372,10 @@
   if (AllSymbols.empty() && Obj->isELF())
     addDynamicElfSymbols(Obj, AllSymbols);
 
+  BumpPtrAllocator A;
+  StringSaver Saver(A);
+  addPltEntries(Obj, AllSymbols, Saver);
+
   // Create a mapping from virtual address to section.
   std::vector<std::pair<uint64_t, SectionRef>> SectionAddresses;
   for (SectionRef Sec : Obj->sections())
Index: test/tools/llvm-objdump/X86/plt.test
===================================================================
--- /dev/null
+++ test/tools/llvm-objdump/X86/plt.test
@@ -0,0 +1,6 @@
+// RUN: llvm-objdump -d %p/Inputs/stripped-elf.so | FileCheck %s
+
+# CHECK: Disassembly of section .plt:
+# CHECK: __gmon_start__ at plt:
+# CHECK: __cxa_finalize at plt:
+# CHECK: callq {{.*}} <__cxa_finalize at plt>
Index: test/tools/llvm-objdump/AArch64/plt.test
===================================================================
--- /dev/null
+++ test/tools/llvm-objdump/AArch64/plt.test
@@ -0,0 +1,5 @@
+// RUN: llvm-objdump -d %p/Inputs/simple-inheritance.elf-aarch64 | FileCheck %s
+
+# CHECK: Disassembly of section .plt:
+# CHECK: _Znwm at plt:
+# CHECK: bl {{.*}} <_Znwm at plt>


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