Add a form of addPreserved which takes a string argument, to allow passes

to declare that they preserve other passes without needing to pull in
additional header file or library dependencies. Convert MachineFunctionPass
and CodeGenLICM to make use of this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83555 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 22 insertions, 0 deletions

diff --git a/include/llvm/Pass.h b/include/llvm/Pass.h
index f3f71c8..eb4c922 100644
--- a/include/llvm/Pass.h
+++ b/include/llvm/Pass.h
@@ -46,6 +46,7 @@ class PMStack;
 class AnalysisResolver;
 class PMDataManager;
 class raw_ostream;
+class StringRef;
 
 // AnalysisID - Use the PassInfo to identify a pass...
 typedef const PassInfo* AnalysisID;
@@ -164,6 +165,10 @@ public:
   // or null if it is not known.
   static const PassInfo *lookupPassInfo(intptr_t TI);
 
+  // lookupPassInfo - Return the pass info object for the pass with the given
+  // argument string, or null if it is not known.
+  static const PassInfo *lookupPassInfo(const StringRef &Arg);
+
   /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
   /// get analysis information that might be around, for example to update it.
   /// This is different than getAnalysis in that it can fail (if the analysis
diff --git a/include/llvm/PassAnalysisSupport.h b/include/llvm/PassAnalysisSupport.h
index b09ba45..f339481 100644
--- a/include/llvm/PassAnalysisSupport.h
+++ b/include/llvm/PassAnalysisSupport.h
@@ -24,6 +24,8 @@
 
 namespace llvm {
 
+class StringRef;
+
 // No need to include Pass.h, we are being included by it!
 
 //===----------------------------------------------------------------------===//
@@ -79,6 +81,9 @@ public:
     return *this;
   }
 
+  // addPreserved - Add the specified Pass class to the set of analyses
+  // preserved by this pass.
+  //
   template<class PassClass>
   AnalysisUsage &addPreserved() {
     assert(Pass::getClassPassInfo<PassClass>() && "Pass class not registered!");
@@ -86,6 +91,18 @@ public:
     return *this;
   }
 
+  // addPreserved - Add the Pass with the specified argument string to the set
+  // of analyses preserved by this pass. If no such Pass exists, do nothing.
+  // This can be useful when a pass is trivially preserved, but may not be
+  // linked in. Be careful about spelling!
+  //
+  AnalysisUsage &addPreserved(const StringRef &Arg) {
+    const PassInfo *PI = Pass::lookupPassInfo(Arg);
+    // If the pass exists, preserve it. Otherwise silently do nothing.
+    if (PI) Preserved.push_back(PI);
+    return *this;
+  }
+
   // setPreservesAll - Set by analyses that do not transform their input at all
   void setPreservesAll() { PreservesAll = true; }
   bool getPreservesAll() const { return PreservesAll; }