verify-di: Implement DebugInfoVerifier

Implement DebugInfoVerifier, which steals verification relying on
DebugInfoFinder from Verifier.

  - Adds LegacyDebugInfoVerifierPassPass, a ModulePass which wraps
    DebugInfoVerifier.  Uses -verify-di command-line flag.

  - Change verifyModule() to invoke DebugInfoVerifier as well as
    Verifier.

  - Add a call to createDebugInfoVerifierPass() wherever there was a
    call to createVerifierPass().

This implementation as a module pass should sidestep efficiency issues,
allowing us to turn debug info verification back on.

<rdar://problem/15500563>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206300 91177308-0d34-0410-b5e6-96231b3b80d8

tools/bugpoint/CrashDebugger.cpp

@@ -410,6 +410,7 @@ bool ReduceCrashingInstructions::TestInsts(std::vector<const Instruction*>
   // Verify that this is still valid.
   PassManager Passes;
   Passes.add(createVerifierPass());
+  Passes.add(createDebugInfoVerifierPass());
   Passes.run(*M);
 
   // Try running on the hacked up program...

tools/llvm-stress/llvm-stress.cpp

@@ -713,6 +713,7 @@ int main(int argc, char **argv) {
 
   PassManager Passes;
   Passes.add(createVerifierPass());
+  Passes.add(createDebugInfoVerifierPass());
   Passes.add(createPrintModulePass(Out->os()));
   Passes.run(*M.get());
   Out->keep();

tools/opt/opt.cpp

@@ -191,7 +191,10 @@ static inline void addPass(PassManagerBase &PM, Pass *P) {
   PM.add(P);
 
   // If we are verifying all of the intermediate steps, add the verifier...
-  if (VerifyEach) PM.add(createVerifierPass());
+  if (VerifyEach) {
+    PM.add(createVerifierPass());
+    PM.add(createDebugInfoVerifierPass());
+  }
 }
 
 /// AddOptimizationPasses - This routine adds optimization passes
@@ -201,7 +204,8 @@ static inline void addPass(PassManagerBase &PM, Pass *P) {
 /// OptLevel - Optimization Level
 static void AddOptimizationPasses(PassManagerBase &MPM,FunctionPassManager &FPM,
                                   unsigned OptLevel, unsigned SizeLevel) {
-  FPM.add(createVerifierPass());                  // Verify that input is correct
+  FPM.add(createVerifierPass());          // Verify that input is correct
+  MPM.add(createDebugInfoVerifierPass()); // Verify that debug info is correct
 
   PassManagerBuilder Builder;
   Builder.OptLevel = OptLevel;
@@ -240,6 +244,9 @@ static void AddStandardCompilePasses(PassManagerBase &PM) {
   if (StripDebug)
     addPass(PM, createStripSymbolsPass(true));
 
+  // Verify debug info only after it's (possibly) stripped.
+  PM.add(createDebugInfoVerifierPass());
+
   if (DisableOptimizations) return;
 
   // -std-compile-opts adds the same module passes as -O3.
@@ -257,6 +264,9 @@ static void AddStandardLinkPasses(PassManagerBase &PM) {
   if (StripDebug)
     addPass(PM, createStripSymbolsPass(true));
 
+  // Verify debug info only after it's (possibly) stripped.
+  PM.add(createDebugInfoVerifierPass());
+
   if (DisableOptimizations) return;
 
   PassManagerBuilder Builder;
@@ -600,8 +610,10 @@ int main(int argc, char **argv) {
   }
 
   // Check that the module is well formed on completion of optimization
-  if (!NoVerify && !VerifyEach)
+  if (!NoVerify && !VerifyEach) {
     Passes.add(createVerifierPass());
+    Passes.add(createDebugInfoVerifierPass());
+  }
 
   // Write bitcode or assembly to the output as the last step...
   if (!NoOutput && !AnalyzeOnly) {