Fix handling unknown branches when parsing switch instructions.

src/PNaClTranslator.cpp

@@ -2415,6 +2415,8 @@ void FunctionParser::ProcessRecord() {
     }
     Ice::CfgNode *DefaultLabel =
         isIRGenDisabled ? nullptr : getBranchBasicBlock(Values[2]);
+    if (DefaultLabel == nullptr)
+      return;
     uint64_t NumCasesRaw = Values[3];
     if (NumCasesRaw > std::numeric_limits<uint32_t>::max()) {
       std::string Buffer;
@@ -2428,10 +2430,10 @@ void FunctionParser::ProcessRecord() {
     // Now recognize each of the cases.
     if (!isValidRecordSize(4 + NumCases * 4, "switch"))
       return;
-    Ice::InstSwitch *Switch =
-        isIRGenDisabled
-            ? nullptr
-            : Ice::InstSwitch::create(Func.get(), NumCases, Cond, DefaultLabel);
+    std::unique_ptr<Ice::InstSwitch> Switch(
+        isIRGenDisabled ? nullptr
+                        : Ice::InstSwitch::create(Func.get(), NumCases, Cond,
+                                                  DefaultLabel));
     unsigned ValCaseIndex = 4; // index to beginning of case entry.
     for (uint32_t CaseIndex = 0; CaseIndex < NumCases;
          ++CaseIndex, ValCaseIndex += 4) {
@@ -2448,11 +2450,13 @@ void FunctionParser::ProcessRecord() {
       if (isIRGenDisabled)
         continue;
       Ice::CfgNode *Label = getBranchBasicBlock(Values[ValCaseIndex + 3]);
+      if (Label == nullptr)
+        return;
       Switch->addBranch(CaseIndex, Value.getSExtValue(), Label);
     }
     if (isIRGenDisabled)
       return;
-    CurrentNode->appendInst(Switch);
+    CurrentNode->appendInst(Switch.release());
     return;
   }
   case naclbitc::FUNC_CODE_INST_UNREACHABLE: {

tests_lit/parse_errs/Inputs/bad-switch-case.tbc

+65535,8,2;
+1,1;
+65535,17,2;
+1,3;
+2;
+7,32;
+21,0,0,1;
+65534;
+8,2,0,0,0;
+65535,19,2;
+5,0;
+65534;
+65535,14,2;
+1,0,83,119,105,116,99,104,86,97,114,105,97,98,108,101;
+65534;
+65535,12,2;
+1,6;
+12,1,1,2,2,1,1,2,3105555534,1,1,8,4;
+11,5;
+11,5;
+11,5;
+11,5;
+10;
+65534;
+65534;

tests_lit/parse_errs/bad-switch-case.test

+; REQUIRES: no_minimal_build
+; RUN: not %pnacl_sz -bitcode-as-text %p/Inputs/bad-switch-case.tbc \
+; RUN:     -bitcode-format=pnacl -notranslate -build-on-read 2>&1 \
+; RUN:   | FileCheck -check-prefix=BAD-SWITCH-CASE %s
+
+; BAD-SWITCH-CASE: Reference to basic block 3105555534 not found. Must be less than 6