llvm-readobj: add support to dump COFF export tables

This enhances llvm-readobj to print out the COFF export table, similar to the
-coff-import option.  This is useful for testing in lld.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225120 91177308-0d34-0410-b5e6-96231b3b80d8

test/tools/llvm-readobj/coff-exports.test

@@ -0,0 +1,11 @@
+RUN: llvm-readobj -coff-exports %p/Inputs/export-x86.dll | FileCheck %s -check-prefix CHECK -check-prefix CHECK-X86
+RUN: llvm-readobj -coff-exports %p/Inputs/export-x64.dll | FileCheck %s -check-prefix CHECK -check-prefix CHECK-X64
+RUN: llvm-readobj -coff-exports %p/Inputs/export-arm.dll | FileCheck %s -check-prefix CHECK -check-prefix CHECK-ARM
+
+CHECK: Export {
+CHECK:   Ordinal: 1
+CHECK:   Name: function
+CHECK-X86:   RVA: 0x1000
+CHECK-X64:   RVA: 0x1000
+CHECK-ARM:   RVA: 0x1001
+CHECK: }

tools/llvm-readobj/COFFDumper.cpp

@@ -57,6 +57,7 @@ public:
   void printDynamicSymbols() override;
   void printUnwindInfo() override;
   void printCOFFImports() override;
+  void printCOFFExports() override;
   void printCOFFDirectives() override;
   void printCOFFBaseReloc() override;
 
@@ -1062,6 +1063,26 @@ void COFFDumper::printCOFFImports() {
   }
 }
 
+void COFFDumper::printCOFFExports() {
+  for (const ExportDirectoryEntryRef &E : Obj->export_directories()) {
+    DictScope Export(W, "Export");
+
+    StringRef Name;
+    uint32_t Ordinal, RVA;
+
+    if (error(E.getSymbolName(Name)))
+      continue;
+    if (error(E.getOrdinal(Ordinal)))
+      continue;
+    if (error(E.getExportRVA(RVA)))
+      continue;
+
+    W.printNumber("Ordinal", Ordinal);
+    W.printString("Name", Name);
+    W.printHex("RVA", RVA);
+  }
+}
+
 void COFFDumper::printCOFFDirectives() {
   for (const SectionRef &Section : Obj->sections()) {
     StringRef Contents;

tools/llvm-readobj/ObjDumper.h

@@ -45,6 +45,7 @@ public:
 
   // Only implemented for PE/COFF.
   virtual void printCOFFImports() { }
+  virtual void printCOFFExports() { }
   virtual void printCOFFDirectives() { }
   virtual void printCOFFBaseReloc() { }
 

tools/llvm-readobj/llvm-readobj.cpp

@@ -146,6 +146,10 @@ namespace opts {
   cl::opt<bool>
   COFFImports("coff-imports", cl::desc("Display the PE/COFF import table"));
 
+  // -coff-exports
+  cl::opt<bool>
+  COFFExports("coff-exports", cl::desc("Display the PE/COFF export table"));
+
   // -coff-directives
   cl::opt<bool>
   COFFDirectives("coff-directives",
@@ -282,6 +286,8 @@ static void dumpObject(const ObjectFile *Obj) {
       Dumper->printMipsPLTGOT();
   if (opts::COFFImports)
     Dumper->printCOFFImports();
+  if (opts::COFFExports)
+    Dumper->printCOFFExports();
   if (opts::COFFDirectives)
     Dumper->printCOFFDirectives();
   if (opts::COFFBaseRelocs)