[NewPM] teach -passes= to emit meaningful error messages

All the PassBuilder::parse interfaces now return descriptive StringError
instead of a plain bool. It allows to make -passes/aa-pipeline parsing
errors context-specific and thus less confusing.

TODO: ideally we should also make suggestions for misspelled pass names,
but that requires some extensions to PassBuilder.

Reviewed By: philip.pfaffe, chandlerc
Differential Revision: https://reviews.llvm.org/D53246

llvm-svn: 344685

1 files changed, 7 insertions, 7 deletions

diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index 20fc40de4b9..1f9d60a5bdf 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -162,7 +162,7 @@ static void runNewPMPasses(Config &Conf, Module &Mod, TargetMachine *TM,
   AAManager AA;
 
   // Parse a custom AA pipeline if asked to.
-  if (!PB.parseAAPipeline(AA, "default"))
+  if (auto Err = PB.parseAAPipeline(AA, "default"))
     report_fatal_error("Error parsing default AA pipeline");
 
   LoopAnalysisManager LAM(Conf.DebugPassManager);
@@ -221,9 +221,9 @@ static void runNewPMCustomPasses(Module &Mod, TargetMachine *TM,
 
   // Parse a custom AA pipeline if asked to.
   if (!AAPipelineDesc.empty())
-    if (!PB.parseAAPipeline(AA, AAPipelineDesc))
-      report_fatal_error("unable to parse AA pipeline description: " +
-                         AAPipelineDesc);
+    if (auto Err = PB.parseAAPipeline(AA, AAPipelineDesc))
+      report_fatal_error("unable to parse AA pipeline description '" +
+                         AAPipelineDesc + "': " + toString(std::move(Err)));
 
   LoopAnalysisManager LAM;
   FunctionAnalysisManager FAM;
@@ -246,9 +246,9 @@ static void runNewPMCustomPasses(Module &Mod, TargetMachine *TM,
   MPM.addPass(VerifierPass());
 
   // Now, add all the passes we've been requested to.
-  if (!PB.parsePassPipeline(MPM, PipelineDesc))
-    report_fatal_error("unable to parse pass pipeline description: " +
-                       PipelineDesc);
+  if (auto Err = PB.parsePassPipeline(MPM, PipelineDesc))
+    report_fatal_error("unable to parse pass pipeline description '" +
+                       PipelineDesc + "': " + toString(std::move(Err)));
 
   if (!DisableVerify)
     MPM.addPass(VerifierPass());