Check for metadata in PNaCl ABI checker.

lib/Analysis/NaCl/PNaClABIVerifyFunctions.cpp

Index: lib/Analysis/NaCl/PNaClABIVerifyFunctions.cpp
diff --git a/lib/Analysis/NaCl/PNaClABIVerifyFunctions.cpp b/lib/Analysis/NaCl/PNaClABIVerifyFunctions.cpp
index cd3ede4b5872bc35a979aa18fbd9cec9f0eb8348..fc1b5821c6e71b6918282d90fd126bc4d33ee21f 100644
--- a/lib/Analysis/NaCl/PNaClABIVerifyFunctions.cpp
+++ b/lib/Analysis/NaCl/PNaClABIVerifyFunctions.cpp
@@ -17,6 +17,7 @@
 #include "llvm/Analysis/NaCl.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/Support/raw_ostream.h"
 
@@ -33,13 +34,16 @@ class PNaClABIVerifyFunctions : public FunctionPass {
   PNaClABIVerifyFunctions() :
       FunctionPass(ID),
       Reporter(new PNaClABIErrorReporter),
-      ReporterIsOwned(true) {
+      ReporterIsOwned(true),
+      AllowDebugMetadata(false) {
     initializePNaClABIVerifyFunctionsPass(*PassRegistry::getPassRegistry());
   }
-  explicit PNaClABIVerifyFunctions(PNaClABIErrorReporter *Reporter_) :
+  PNaClABIVerifyFunctions(PNaClABIErrorReporter *Reporter_,
+                          bool AllowDebugMetadata_) :
       FunctionPass(ID),
       Reporter(Reporter_),
-      ReporterIsOwned(false) {
+      ReporterIsOwned(false),
+      AllowDebugMetadata(AllowDebugMetadata_) {

[Mark Seaborn, 2013/04/25 18:04:32]

I think using a trailing underscore is not LLVM style.  You could write
"AllowDebugMetadata(AllowDebugMetadata)" instead -- it works.

[jvoung (off chromium), 2013/04/25 23:22:20]

Hmm it's not that consistent =)  MCAssembler uses underscores, but removing this
argument anyway, and using the commandline flag.

     initializePNaClABIVerifyFunctionsPass(*PassRegistry::getPassRegistry());
   }
   ~PNaClABIVerifyFunctions() {
@@ -49,13 +53,28 @@ class PNaClABIVerifyFunctions : public FunctionPass {
   bool runOnFunction(Function &F);
   virtual void print(raw_ostream &O, const Module *M) const;
  private:
+  bool IsWhiteListedMetadata(unsigned MDKind);

[Mark Seaborn, 2013/04/25 18:04:32]

Nit: "IsWhitelisted" ("whitelisting" is one word)

[jvoung (off chromium), 2013/04/25 23:22:20]

Done.

   PNaClABITypeChecker TC;
   PNaClABIErrorReporter *Reporter;
   bool ReporterIsOwned;
+  bool AllowDebugMetadata;
 };
 
+// There's no built-in way to get the name of an MDNode, so use a
+// string ostream to print it.
+std::string getMDNodeString(const MDNode *MD) {
+  std::string s;
+  raw_string_ostream N(s);
+  MD->print(N);
+  return N.str();
+}
+
 } // and anonymous namespace
 
+bool PNaClABIVerifyFunctions::IsWhiteListedMetadata(unsigned MDKind) {
+  return MDKind == LLVMContext::MD_dbg && AllowDebugMetadata;
+}
+
 bool PNaClABIVerifyFunctions::runOnFunction(Function &F) {
   // TODO: only report one error per instruction?
   for (Function::const_iterator FI = F.begin(), FE = F.end();
@@ -181,15 +200,25 @@ bool PNaClABIVerifyFunctions::runOnFunction(Function &F) {
         }
       }
 
-      // Get types hiding in metadata attached to the instruction
+      // Check instruction attachment metadata.
       SmallVector<std::pair<unsigned, MDNode*>, 4> MDForInst;
-      BBI->getAllMetadataOtherThanDebugLoc(MDForInst);
+      BBI->getAllMetadata(MDForInst);
+
       for (unsigned i = 0, e = MDForInst.size(); i != e; i++) {
-        Type *T = TC.checkTypesInMDNode(MDForInst[i].second);
-        if (T) {
-          Reporter->addError() << "Function " << F.getName() <<
-              " has instruction metadata containing disallowed type: " <<
-              PNaClABITypeChecker::getTypeName(T) << "\n";
+        if (!IsWhiteListedMetadata(MDForInst[i].first)) {
+            Reporter->addError()

[Mark Seaborn, 2013/04/25 18:04:32]

Fix indentation: remove 2 spaces

[jvoung (off chromium), 2013/04/25 23:22:20]

Done.

+                << "Function " << F.getName()
+                << " has disallowed instruction metadata: "
+                << getMDNodeString(MDForInst[i].second) << "\n";
+        } else {
+          // If allowed, check the types hiding in the metadata.
+          Type *T = TC.checkTypesInMDNode(MDForInst[i].second);
+          if (T) {
+            Reporter->addError()
+                << "Function " << F.getName()
+                << " has instruction metadata containing disallowed type: "
+                << PNaClABITypeChecker::getTypeName(T) << "\n";
+          }
         }
       }
     }
@@ -213,6 +242,7 @@ INITIALIZE_PASS(PNaClABIVerifyFunctions, "verify-pnaclabi-functions",
                 "Verify functions for PNaCl", false, true)
 
 FunctionPass *llvm::createPNaClABIVerifyFunctionsPass(
-    PNaClABIErrorReporter *Reporter) {
-  return new PNaClABIVerifyFunctions(Reporter);
+    PNaClABIErrorReporter *Reporter,
+    bool AllowDebugMetadata) {
+  return new PNaClABIVerifyFunctions(Reporter, AllowDebugMetadata);
 }