[lld][MachO] Add option to suppress mismatch profile errors

lld/MachO/Config.h

@@ -208,6 +208,7 @@ struct Configuration {
   bool ltoDebugPassManager = false;
   bool csProfileGenerate = false;
   llvm::StringRef csProfilePath;
+  bool pgoWarnMismatch;
 
   bool callGraphProfileSort = false;
   llvm::StringRef printSymbolOrder;

lld/MachO/Driver.cpp

@@ -1670,6 +1670,8 @@ bool link(ArrayRef<const char *> argsArr, llvm::raw_ostream &stdoutOS,
   config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
   config->csProfileGenerate = args.hasArg(OPT_cs_profile_generate);
   config->csProfilePath = args.getLastArgValue(OPT_cs_profile_path);
+  config->pgoWarnMismatch =
+      args.hasFlag(OPT_pgo_warn_mismatch, OPT_no_pgo_warn_mismatch, true);
   config->generateUuid = !args.hasArg(OPT_no_uuid);
 
   for (const Arg *arg : args.filtered(OPT_alias)) {

lld/MachO/LTO.cpp

@@ -71,6 +71,7 @@ static lto::Config createConfig() {
   c.DebugPassManager = config->ltoDebugPassManager;
   c.CSIRProfile = std::string(config->csProfilePath);
   c.RunCSIRInstr = config->csProfileGenerate;
+  c.PGOWarnMismatch = config->pgoWarnMismatch;
   c.OptLevel = config->ltoo;
   c.CGOptLevel = config->ltoCgo;
   if (config->saveTemps)

lld/MachO/Options.td

@@ -1,5 +1,10 @@
 include "llvm/Option/OptParser.td"
 
+multiclass BB<string name, string help1, string help2> {
+  def NAME: Flag<["--"], name>, HelpText<help1>;
+  def no_ # NAME: Flag<["--"], "no-" # name>, HelpText<help2>;
+}
+
 // Flags that lld/MachO understands but ld64 doesn't. These take
 // '--' instead of '-' and use dashes instead of underscores, so
 // they don't collide with the ld64 compat options.
@@ -130,6 +135,9 @@ def cs_profile_generate: Flag<["--"], "cs-profile-generate">,
     HelpText<"Perform context senstive PGO instrumentation">, Group<grp_lld>;
 def cs_profile_path: Joined<["--"], "cs-profile-path=">,
     HelpText<"Context sensitive profile file path">, Group<grp_lld>;
+defm pgo_warn_mismatch: BB<"pgo-warn-mismatch",
+  "turn on warnings about profile cfg mismatch (default)",
+  "turn off warnings about profile cfg mismatch">, Group<grp_lld>;
 
 // This is a complete Options.td compiled from Apple's ld(1) manpage
 // dated 2018-03-07 and cross checked with ld64 source code in repo

lld/test/MachO/pgo-warn-mismatch.ll

@@ -0,0 +1,34 @@
+; REQUIRES: x86
+
+; RUN: rm -rf %t && split-file %s %t
+; RUN: llvm-as %t/a.ll -o %t/a.o
+; RUN: llvm-profdata merge %t/cs.proftext -o %t/cs.profdata
+
+;; Ensure lld generates warnings for profile cfg mismatch.
+; RUN: not %lld -dylib --cs-profile-path=%t/cs.profdata %t/a.o -o /dev/null 2>&1 | FileCheck %s
+; RUN: not %lld -dylib --cs-profile-path=%t/cs.profdata --pgo-warn-mismatch %t/a.o -o /dev/null 2>&1 | FileCheck %s
+
+;; Ensure lld will not generate warnings for profile cfg mismatch.
+; RUN: %lld -dylib --cs-profile-path=%t/cs.profdata --no-pgo-warn-mismatch %t/a.o -o /dev/null
+
+; CHECK: function control flow change detected (hash mismatch) foo Hash = [[#]]
+
+;--- a.ll
+target triple = "x86_64-apple-darwin"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+define i32 @foo() {
+entry:
+  ret i32 0
+}
+
+;--- cs.proftext
+:csir
+_foo
+# Func Hash:
+2277602155505015273
+# Num Counters:
+2
+# Counter Values:
+1
+0