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.

llvm-svn: 77691

1 files changed, 45 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineFunctionAnalysis.cpp b/llvm/lib/CodeGen/MachineFunctionAnalysis.cpp
new file mode 100644
index 0000000..8b7dba8
--- /dev/null
+++ b/llvm/lib/CodeGen/MachineFunctionAnalysis.cpp
@@ -0,0 +1,45 @@
+//===-- MachineFunctionAnalysis.cpp ---------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the definitions of the MachineFunctionAnalysis members.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/MachineFunctionAnalysis.h"
+#include "llvm/CodeGen/MachineFunction.h"
+using namespace llvm;
+
+// Register this pass with PassInfo directly to avoid having to define
+// a default constructor.
+static PassInfo
+X("Machine Function Analysis", "machine-function-analysis",
+  intptr_t(&MachineFunctionAnalysis::ID), 0,
+  /*CFGOnly=*/false, /*is_analysis=*/true);
+
+char MachineFunctionAnalysis::ID = 0;
+
+MachineFunctionAnalysis::MachineFunctionAnalysis(TargetMachine &tm,
+                                                 CodeGenOpt::Level OL) :
+  FunctionPass(&ID), TM(tm), OptLevel(OL), MF(0) {
+}
+
+bool MachineFunctionAnalysis::runOnFunction(Function &F) {
+  assert(!MF && "MachineFunctionAnalysis already initialized!");
+  MF = new MachineFunction(&F, TM);
+  return false;
+}
+
+void MachineFunctionAnalysis::releaseMemory() {
+  delete MF;
+  MF = 0;
+}
+
+void MachineFunctionAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.setPreservesAll();
+}