Fix two rather subtle internal vs. external linker issues.

I'll admit I'm not entirely satisfied with this change, but it seemed
the cleanest option. Other suggestions quite welcome

The issue is that the traits specializations have static methods which
return the typedef'ed PHI_iterator type. In both the IR and MI layers
this is typedef'ed to a custom iterator class defined in an anonymous
namespace giving the types and the functions returning them internal
linkage. However, because the traits specialization is defined in the
'llvm' namespace (where it has to be, specialized template lives there),
and is in turn used in the templated implementation of the SSAUpdater.
This led to the linkage conflict that Clang now warns about.

The simplest solution to me was just to define the PHI_iterator as
a nested class inside the trait specialization. That way it still
doesn't get scoped widely, it can't be accidentally reused somewhere,
etc. This is a little gross just because nested class definitions are
a little gross, but the alternatives seem more ad-hoc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158799 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 20 insertions, 25 deletions

diff --git a/lib/CodeGen/MachineSSAUpdater.cpp b/lib/CodeGen/MachineSSAUpdater.cpp
index 070a55704d..acb1ee6cb6 100644
--- a/lib/CodeGen/MachineSSAUpdater.cpp
+++ b/lib/CodeGen/MachineSSAUpdater.cpp
@@ -241,30 +241,6 @@ void MachineSSAUpdater::ReplaceRegWith(unsigned OldReg, unsigned NewReg) {
       I->second = NewReg;
 }
 
-/// MachinePHIiter - Iterator for PHI operands.  This is used for the
-/// PHI_iterator in the SSAUpdaterImpl template.
-namespace {
-  class MachinePHIiter {
-  private:
-    MachineInstr *PHI;
-    unsigned idx;
- 
-  public:
-    explicit MachinePHIiter(MachineInstr *P) // begin iterator
-      : PHI(P), idx(1) {}
-    MachinePHIiter(MachineInstr *P, bool) // end iterator
-      : PHI(P), idx(PHI->getNumOperands()) {}
-
-    MachinePHIiter &operator++() { idx += 2; return *this; } 
-    bool operator==(const MachinePHIiter& x) const { return idx == x.idx; }
-    bool operator!=(const MachinePHIiter& x) const { return !operator==(x); }
-    unsigned getIncomingValue() { return PHI->getOperand(idx).getReg(); }
-    MachineBasicBlock *getIncomingBlock() {
-      return PHI->getOperand(idx+1).getMBB();
-    }
-  };
-}
-
 /// SSAUpdaterTraits<MachineSSAUpdater> - Traits for the SSAUpdaterImpl
 /// template, specialized for MachineSSAUpdater.
 namespace llvm {
@@ -279,7 +255,26 @@ public:
   static BlkSucc_iterator BlkSucc_begin(BlkT *BB) { return BB->succ_begin(); }
   static BlkSucc_iterator BlkSucc_end(BlkT *BB) { return BB->succ_end(); }
 
-  typedef MachinePHIiter PHI_iterator;
+  /// Iterator for PHI operands.
+  class PHI_iterator {
+  private:
+    MachineInstr *PHI;
+    unsigned idx;
+ 
+  public:
+    explicit PHI_iterator(MachineInstr *P) // begin iterator
+      : PHI(P), idx(1) {}
+    PHI_iterator(MachineInstr *P, bool) // end iterator
+      : PHI(P), idx(PHI->getNumOperands()) {}
+
+    PHI_iterator &operator++() { idx += 2; return *this; } 
+    bool operator==(const PHI_iterator& x) const { return idx == x.idx; }
+    bool operator!=(const PHI_iterator& x) const { return !operator==(x); }
+    unsigned getIncomingValue() { return PHI->getOperand(idx).getReg(); }
+    MachineBasicBlock *getIncomingBlock() {
+      return PHI->getOperand(idx+1).getMBB();
+    }
+  };
   static inline PHI_iterator PHI_begin(PhiT *PHI) { return PHI_iterator(PHI); }
   static inline PHI_iterator PHI_end(PhiT *PHI) {
     return PHI_iterator(PHI, true);