commit 433e5b9b122a0f25b5db40013931d33d1b0220d2
author Reid Kleckner <rnk@google.com> Mon Nov 16 21:05:53 2015 +0000
committer Reid Kleckner <rnk@google.com> Mon Nov 16 21:05:53 2015 +0000
tree 345462ea61b91dd5f16405b689cd9132843106f5
parent c8123ca00e2cce1a2162dd439ab7c238cf97a1b3

Merge r251567:

Fix the calling convention of Mingw64 long double values

GCC uses the x87DoubleExtended model for long doubles, and passes them
indirectly by address through function calls.

Also replace the existing mingw-long-double assembly emitting test with
an IR-level test.

llvm-svn: 253250

clang/lib/Basic/Targets.cpp

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index e4db004..9e44f7d 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -3968,7 +3968,13 @@
 class MinGWX86_64TargetInfo : public WindowsX86_64TargetInfo {
 public:
   MinGWX86_64TargetInfo(const llvm::Triple &Triple)
-      : WindowsX86_64TargetInfo(Triple) {}
+      : WindowsX86_64TargetInfo(Triple) {
+    // Mingw64 rounds long double size and alignment up to 16 bytes, but sticks
+    // with x86 FP ops. Weird.
+    LongDoubleWidth = LongDoubleAlign = 128;
+    LongDoubleFormat = &llvm::APFloat::x87DoubleExtended;
+  }
+
   void getTargetDefines(const LangOptions &Opts,
                         MacroBuilder &Builder) const override {
     WindowsX86_64TargetInfo::getTargetDefines(Opts, Builder);

clang/lib/CodeGen/TargetInfo.cpp

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 960028a..fa31dc3 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -1552,12 +1552,10 @@
 
 /// WinX86_64ABIInfo - The Windows X86_64 ABI information.
 class WinX86_64ABIInfo : public ABIInfo {
-
-  ABIArgInfo classify(QualType Ty, unsigned &FreeSSERegs,
-                      bool IsReturnType) const;
-
 public:
-  WinX86_64ABIInfo(CodeGen::CodeGenTypes &CGT) : ABIInfo(CGT) {}
+  WinX86_64ABIInfo(CodeGen::CodeGenTypes &CGT)
+      : ABIInfo(CGT),
+        IsMingw64(getTarget().getTriple().isWindowsGNUEnvironment()) {}
 
   void computeInfo(CGFunctionInfo &FI) const override;
 
@@ -1574,6 +1572,12 @@
     // FIXME: Assumes vectorcall is in use.
     return isX86VectorCallAggregateSmallEnough(NumMembers);
   }
+
+private:
+  ABIArgInfo classify(QualType Ty, unsigned &FreeSSERegs,
+                      bool IsReturnType) const;
+
+  bool IsMingw64;
 };
 
 class X86_64TargetCodeGenInfo : public TargetCodeGenInfo {
@@ -3059,7 +3063,7 @@
 
   TypeInfo Info = getContext().getTypeInfo(Ty);
   uint64_t Width = Info.Width;
-  unsigned Align = getContext().toCharUnitsFromBits(Info.Align).getQuantity();
+  CharUnits Align = getContext().toCharUnitsFromBits(Info.Align);
 
   const RecordType *RT = Ty->getAs<RecordType>();
   if (RT) {
@@ -3070,7 +3074,6 @@
 
     if (RT->getDecl()->hasFlexibleArrayMember())
       return ABIArgInfo::getIndirect(0, /*ByVal=*/false);
-
   }
 
   // vectorcall adds the concept of a homogenous vector aggregate, similar to
@@ -3112,6 +3115,14 @@
   if (BT && BT->getKind() == BuiltinType::Bool)
     return ABIArgInfo::getExtend();
 
+  // Mingw64 GCC uses the old 80 bit extended precision floating point unit. It
+  // passes them indirectly through memory.
+  if (IsMingw64 && BT && BT->getKind() == BuiltinType::LongDouble) {
+    const llvm::fltSemantics *LDF = &getTarget().getLongDoubleFormat();
+    if (LDF == &llvm::APFloat::x87DoubleExtended)
+      return ABIArgInfo::getIndirect(Align, /*ByVal=*/false);
+  }
+
   return ABIArgInfo::getDirect();
 }