Add a -print-cond-fail-messages-include-function-name option

Additionally, also consider the function name as the key to base cond_fail
removal on under `-cond-fail-config-file`.

Author: aschwaighofer

lib/SILOptimizer/Mandatory/IRGenPrepare.cpp

@@ -38,6 +38,11 @@ using namespace swift;
 static llvm::cl::opt<bool> PrintCondFailMessages(
   "print-cond-fail-messages", llvm::cl::init(false),
   llvm::cl::desc("print cond_fail messages"));
+static llvm::cl::opt<bool> IncludeCondFailMessagesFunction(
+  "print-cond-fail-messages-include-function-name", llvm::cl::init(false),
+  llvm::cl::desc("when printing cond_fail messages include"
+                 "the current SIL function name"));
+
 static llvm::DenseSet<StringRef> CondFailMessages;
 
 static bool cleanFunction(SILFunction &fn) {
@@ -64,7 +69,11 @@ static bool cleanFunction(SILFunction &fn) {
       //   ```
       if (PrintCondFailMessages) {
         if (auto CFI = dyn_cast<CondFailInst>(inst)) {
-          auto msg = CFI->getMessage();
+          auto msg = CFI->getMessage().str();
+          if (IncludeCondFailMessagesFunction) {
+            msg.append(" in ");
+            msg.append(fn.getName().str());
+          }
           if (CondFailMessages.insert(msg).second)
             llvm::dbgs() << "cond_fail message encountered: " << msg << "\n";
         }

lib/SILOptimizer/SILCombiner/SILCombine.cpp

@@ -707,6 +707,8 @@ void SwiftPassInvocation::eraseInstruction(SILInstruction *inst) {
   }
 }
 
+// cond_fail removal based on cond_fail message and containing function name.
+//
 // The standard library uses _precondition calls which have a message argument.
 //
 // Allow disabling the generated cond_fail by these message arguments.
@@ -728,6 +730,10 @@ void SwiftPassInvocation::eraseInstruction(SILInstruction *inst) {
 //
 // The optimizer will remove these cond_fails if the swift frontend is invoked
 // with -Xllvm -cond-fail-config-file=/path/to/disable_cond_fails.
+//
+// Additionally, also interpret the lines as function names and check whether
+// the current cond_fail is contained in a listed function when considering
+// whether to remove it.
 static llvm::cl::opt<std::string> CondFailConfigFile(
     "cond-fail-config-file", llvm::cl::init(""),
     llvm::cl::desc("read the cond_fail message strings to elimimate from file"));
@@ -750,6 +756,13 @@ bool SILCombiner::shouldRemoveCondFail(CondFailInst &CFI) {
     }
     fs.close();
   }
+  // Check whether the cond_fail's containing function was listed in the config
+  // file.
+  if (CondFailsToRemove.find(CFI.getFunction()->getName().str()) !=
+      CondFailsToRemove.end())
+    return true;
+
+  // Check whether the cond_fail's message was listed in the config file.
   auto message = CFI.getMessage();
   return CondFailsToRemove.find(message.str()) != CondFailsToRemove.end();
 }