Reapply r77654 with a fix: MachineFunctionPass's getAnalysisUsage

shouldn't do AU.setPreservesCFG(), because even though CodeGen passes
don't modify the LLVM IR CFG, they may modify the MachineFunction CFG,
and passes like MachineLoop are registered with isCFGOnly set to true.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77691 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 5 deletions

diff --git a/include/llvm/CodeGen/MachineFunctionPass.h b/include/llvm/CodeGen/MachineFunctionPass.h
index 6b5e64a..6f7c216 100644
--- a/include/llvm/CodeGen/MachineFunctionPass.h
+++ b/include/llvm/CodeGen/MachineFunctionPass.h
@@ -24,19 +24,25 @@
 
 namespace llvm {
 
-  // FIXME: This pass should declare that the pass does not invalidate any LLVM
-  // passes.
-struct MachineFunctionPass : public FunctionPass {
+/// MachineFunctionPass - This class adapts the FunctionPass interface to
+/// allow convenient creation of passes that operate on the MachineFunction
+/// representation. Instead of overriding runOnFunction, subclasses
+/// override runOnMachineFunction.
+class MachineFunctionPass : public FunctionPass {
+protected:
   explicit MachineFunctionPass(intptr_t ID) : FunctionPass(ID) {}
   explicit MachineFunctionPass(void *ID) : FunctionPass(ID) {}
 
-protected:
   /// runOnMachineFunction - This method must be overloaded to perform the
   /// desired machine code transformation or analysis.
   ///
   virtual bool runOnMachineFunction(MachineFunction &MF) = 0;
 
-public:
+  /// getAnalysisUsage - Subclasses that override getAnalysisUsage
+  /// must call this.
+  virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+
+private:
   bool runOnFunction(Function &F);
 };