X86-Windows: Emit an undefined global __fltused symbol when targeting Windows

if any floating point arguments are passed to an external function.

llvm-svn: 116665

1 files changed, 20 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index ebc6d3837e8..04c424f6729 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -15,6 +15,7 @@
 #include "SDNodeDbgValue.h"
 #include "SelectionDAGBuilder.h"
 #include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/PostOrderIterator.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/ConstantFolding.h"
@@ -5019,6 +5020,25 @@ void SelectionDAGBuilder::visitCall(const CallInst &I) {
       }
     }
 
+    // See if any floating point values are being passed to this external
+    // function. This is used to emit an undefined reference to fltused on
+    // Windows.
+    if (!F->hasLocalLinkage() && F->hasName()) {
+      MachineModuleInfo &MMI = DAG.getMachineFunction().getMMI();
+      for (unsigned i = 0, e = I.getNumArgOperands(); i != e &&
+                  !MMI.callsExternalFunctionWithFloatingPointArguments(); ++i) {
+        const Type* T = I.getArgOperand(i)->getType();
+        for (po_iterator<const Type*> i = po_begin(T),
+                                      e = po_end(T);
+                                      i != e; ++i) {
+          if (i->isFloatingPointTy()) {
+            MMI.setCallsExternalFunctionWithFloatingPointArguments(true);
+            break;
+          }
+        }
+      }
+    }
+
     // Check for well-known libc/libm calls.  If the function is internal, it
     // can't be a library call.
     if (!F->hasLocalLinkage() && F->hasName()) {