Check for metadata in PNaCl ABI checker.

lib/Analysis/NaCl/PNaClABIVerifyModule.cpp

Index: lib/Analysis/NaCl/PNaClABIVerifyModule.cpp
diff --git a/lib/Analysis/NaCl/PNaClABIVerifyModule.cpp b/lib/Analysis/NaCl/PNaClABIVerifyModule.cpp
index 88914c85a8a336b85630a35d754c213ac2ba9c05..a1818f7eb02ff5a273cd80345fd9046dc6649634 100644
--- a/lib/Analysis/NaCl/PNaClABIVerifyModule.cpp
+++ b/lib/Analysis/NaCl/PNaClABIVerifyModule.cpp
@@ -23,6 +23,13 @@
 #include "PNaClABITypeChecker.h"
 using namespace llvm;
 
+namespace llvm {
+cl::opt<bool>
+PNaClABIAllowDebugMetadata("pnaclabi-allow-debug-metadata",
+  cl::desc("Allow debug metadata during PNaCl ABI verification."),
+  cl::init(false));
+}
+
 namespace {
 // This pass should not touch function bodies, to stay streaming-friendly
 class PNaClABIVerifyModule : public ModulePass {
@@ -48,6 +55,7 @@ class PNaClABIVerifyModule : public ModulePass {
   virtual void print(raw_ostream &O, const Module *M) const;
  private:
   void CheckGlobalValueCommon(const GlobalValue *GV);
+  bool IsWhitelistedMetadata(const NamedMDNode *MD);
   PNaClABITypeChecker TC;
   PNaClABIErrorReporter *Reporter;
   bool ReporterIsOwned;
@@ -105,6 +113,11 @@ void PNaClABIVerifyModule::CheckGlobalValueCommon(const GlobalValue *GV) {
   }
 }
 
+bool PNaClABIVerifyModule::IsWhitelistedMetadata(const NamedMDNode* MD) {
+  return MD->getName().startswith("llvm.dbg.")
+      && llvm::PNaClABIAllowDebugMetadata;
+}
+
 bool PNaClABIVerifyModule::runOnModule(Module &M) {
   for (Module::const_global_iterator MI = M.global_begin(), ME = M.global_end();
        MI != ME; ++MI) {
@@ -174,11 +187,17 @@ bool PNaClABIVerifyModule::runOnModule(Module &M) {
   // Check named metadata nodes
   for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
            E = M.named_metadata_end(); I != E; ++I) {
-    for (unsigned i = 0, e = I->getNumOperands(); i != e; i++) {
-      if (Type *T = TC.checkTypesInMDNode(I->getOperand(i))) {
-        Reporter->addError() << "Named metadata node " << I->getName() <<
-            " refers to disallowed type: " <<
-            PNaClABITypeChecker::getTypeName(T) << "\n";
+    if (!IsWhitelistedMetadata(I)) {
+      Reporter->addError() << "Named metadata node " << I->getName()
+                           << " is disallowed\n";
+    } else {
+      // Check the types in the metadata.
+      for (unsigned i = 0, e = I->getNumOperands(); i != e; i++) {
+        if (Type *T = TC.checkTypesInMDNode(I->getOperand(i))) {
+          Reporter->addError() << "Named metadata node " << I->getName()
+                               << " refers to disallowed type: "
+                               << PNaClABITypeChecker::getTypeName(T) << "\n";
+        }
       }
     }
   }