From ae889d36724efb174e8cc05d26e655c4c4ab8867 Mon Sep 17 00:00:00 2001
From: Justin Lebar <jlebar@google.com>
Date: Wed, 27 Apr 2016 19:08:24 +0000
Subject: [PATCH] Add TargetMachine::addEarlyAsPossiblePasses, and call it from
 opt.

Summary:
This is a hook to allow TargetMachine to install passes at the
EP_EarlyAsPossible PassManagerBuilder extension point.

Reviewers: chandlerc

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D18614

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267763 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Target/TargetMachine.h |  5 +++++
 tools/opt/opt.cpp                   | 31 +++++++++++++++++++----------
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/include/llvm/Target/TargetMachine.h b/include/llvm/Target/TargetMachine.h
index db0a841abda..c41ba0069fa 100644
--- a/include/llvm/Target/TargetMachine.h
+++ b/include/llvm/Target/TargetMachine.h
@@ -217,6 +217,11 @@ public:
   /// uses this to answer queries about the IR.
   virtual TargetIRAnalysis getTargetIRAnalysis();
 
+  /// Add target-specific function passes that should be run as early as
+  /// possible in the optimization pipeline.  Most TargetMachines have no such
+  /// passes.
+  virtual void addEarlyAsPossiblePasses(PassManagerBase &) {}
+
   /// These enums are meant to be passed into addPassesToEmitFile to indicate
   /// what type of file to emit, and returned by it to indicate what type of
   /// file could actually be made.
diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index 91993bfaa32..2286ac9e28d 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -230,7 +230,8 @@ static inline void addPass(legacy::PassManagerBase &PM, Pass *P) {
 /// OptLevel - Optimization Level
 static void AddOptimizationPasses(legacy::PassManagerBase &MPM,
                                   legacy::FunctionPassManager &FPM,
-                                  unsigned OptLevel, unsigned SizeLevel) {
+                                  TargetMachine *TM, unsigned OptLevel,
+                                  unsigned SizeLevel) {
   if (!NoVerify || VerifyEach)
     FPM.add(createVerifierPass()); // Verify that input is correct
 
@@ -260,6 +261,14 @@ static void AddOptimizationPasses(legacy::PassManagerBase &MPM,
   Builder.SLPVectorize =
       DisableSLPVectorization ? false : OptLevel > 1 && SizeLevel < 2;
 
+  // Add target-specific passes that need to run as early as possible.
+  if (TM)
+    Builder.addExtension(
+        PassManagerBuilder::EP_EarlyAsPossible,
+        [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) {
+          TM->addEarlyAsPossiblePasses(PM);
+        });
+
   Builder.populateFunctionPassManager(FPM);
   Builder.populateModulePassManager(MPM);
 }
@@ -519,27 +528,27 @@ int main(int argc, char **argv) {
     }
 
     if (OptLevelO1 && OptLevelO1.getPosition() < PassList.getPosition(i)) {
-      AddOptimizationPasses(Passes, *FPasses, 1, 0);
+      AddOptimizationPasses(Passes, *FPasses, TM.get(), 1, 0);
       OptLevelO1 = false;
     }
 
     if (OptLevelO2 && OptLevelO2.getPosition() < PassList.getPosition(i)) {
-      AddOptimizationPasses(Passes, *FPasses, 2, 0);
+      AddOptimizationPasses(Passes, *FPasses, TM.get(), 2, 0);
       OptLevelO2 = false;
     }
 
     if (OptLevelOs && OptLevelOs.getPosition() < PassList.getPosition(i)) {
-      AddOptimizationPasses(Passes, *FPasses, 2, 1);
+      AddOptimizationPasses(Passes, *FPasses, TM.get(), 2, 1);
       OptLevelOs = false;
     }
 
     if (OptLevelOz && OptLevelOz.getPosition() < PassList.getPosition(i)) {
-      AddOptimizationPasses(Passes, *FPasses, 2, 2);
+      AddOptimizationPasses(Passes, *FPasses, TM.get(), 2, 2);
       OptLevelOz = false;
     }
 
     if (OptLevelO3 && OptLevelO3.getPosition() < PassList.getPosition(i)) {
-      AddOptimizationPasses(Passes, *FPasses, 3, 0);
+      AddOptimizationPasses(Passes, *FPasses, TM.get(), 3, 0);
       OptLevelO3 = false;
     }
 
@@ -591,19 +600,19 @@ int main(int argc, char **argv) {
   }
 
   if (OptLevelO1)
-    AddOptimizationPasses(Passes, *FPasses, 1, 0);
+    AddOptimizationPasses(Passes, *FPasses, TM.get(), 1, 0);
 
   if (OptLevelO2)
-    AddOptimizationPasses(Passes, *FPasses, 2, 0);
+    AddOptimizationPasses(Passes, *FPasses, TM.get(), 2, 0);
 
   if (OptLevelOs)
-    AddOptimizationPasses(Passes, *FPasses, 2, 1);
+    AddOptimizationPasses(Passes, *FPasses, TM.get(), 2, 1);
 
   if (OptLevelOz)
-    AddOptimizationPasses(Passes, *FPasses, 2, 2);
+    AddOptimizationPasses(Passes, *FPasses, TM.get(), 2, 2);
 
   if (OptLevelO3)
-    AddOptimizationPasses(Passes, *FPasses, 3, 0);
+    AddOptimizationPasses(Passes, *FPasses, TM.get(), 3, 0);
 
   if (OptLevelO1 || OptLevelO2 || OptLevelOs || OptLevelOz || OptLevelO3) {
     FPasses->doInitialization();