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

[Joel Galenson via Phabricator via llvm-commits]

jgalenson created this revision.
jgalenson added reviewers: pcc, eugenis, echristo, paulsemel.
Herald added a reviewer: javed.absar.
Herald added a subscriber: llvm-commits.

Repository:
  rL LLVM

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
@@ -1235,6 +1235,37 @@
     llvm_unreachable("Unsupported binary format");
 }
 
+static void addPltEntries(const ObjectFile *Obj,
+                          std::map<SectionRef, SectionSymbolsTy> &AllSymbols,
+                          std::vector<std::string> &PltEntryNames) {
+  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> Name = Symbol.getName();
+      if (!Name)
+        report_error(Obj->getFileName(), Name.takeError());
+      if (Name->empty())
+        continue;
+
+      // We need to keep a permanent copy of the new name so the StringRef in
+      // AllSymbols works.
+      PltEntryNames.push_back((*Name + "@plt").str());
+
+      AllSymbols[*Plt].emplace_back(PltEntry.second, PltEntryNames.back(), SymbolType);
+    }
+  }
+}
+
 static void DisassembleObject(const ObjectFile *Obj, bool InlineRelocs) {
   if (StartAddress > StopAddress)
     error("Start address should be less than stop address");
@@ -1342,6 +1373,9 @@
   if (AllSymbols.empty() && Obj->isELF())
     addDynamicElfSymbols(Obj, AllSymbols);
 
+  std::vector<std::string> PltEntryNames;
+  addPltEntries(Obj, AllSymbols, PltEntryNames);
+
   // 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>
\ No newline at end of file
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>
\ No newline at end of file


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