Stop resetting NoFramePointerElim in TargetMachine::resetTargetOptions.

This is part of the work to remove TargetMachine::resetTargetOptions.

In this patch, instead of updating global variable NoFramePointerElim in
resetTargetOptions, its use in DisableFramePointerElim is replaced with a call
to TargetFrameLowering::noFramePointerElim. This function determines on a
per-function basis if frame pointer elimination should be disabled.

There is no change in functionality except that cl:opt option "disable-fp-elim"
can now override function attribute "no-frame-pointer-elim". 

llvm-svn: 238080

6 files changed, 21 insertions, 17 deletions

diff --git a/llvm/lib/Target/ARM/ARMFastISel.cpp b/llvm/lib/Target/ARM/ARMFastISel.cpp
index 97995d31db8..4175b4af86e 100644
--- a/llvm/lib/Target/ARM/ARMFastISel.cpp
+++ b/llvm/lib/Target/ARM/ARMFastISel.cpp
@@ -3065,23 +3065,9 @@ bool ARMFastISel::fastLowerArguments() {
 namespace llvm {
   FastISel *ARM::createFastISel(FunctionLoweringInfo &funcInfo,
                                 const TargetLibraryInfo *libInfo) {
-    const TargetMachine &TM = funcInfo.MF->getTarget();
-    const ARMSubtarget &STI =
-        static_cast<const ARMSubtarget &>(funcInfo.MF->getSubtarget());
-    // Thumb2 support on iOS; ARM support on iOS, Linux and NaCl.
-    bool UseFastISel = false;
-    UseFastISel |= STI.isTargetMachO() && !STI.isThumb1Only();
-    UseFastISel |= STI.isTargetLinux() && !STI.isThumb();
-    UseFastISel |= STI.isTargetNaCl() && !STI.isThumb();
-
-    if (UseFastISel) {
-      // iOS always has a FP for backtracking, force other targets
-      // to keep their FP when doing FastISel. The emitted code is
-      // currently superior, and in cases like test-suite's lencod
-      // FastISel isn't quite correct when FP is eliminated.
-      TM.Options.NoFramePointerElim = true;
+    if (funcInfo.MF->getSubtarget<ARMSubtarget>().useFastISel())
       return new ARMFastISel(funcInfo, libInfo);
-    }
+
     return nullptr;
   }
 }
diff --git a/llvm/lib/Target/ARM/ARMFrameLowering.cpp b/llvm/lib/Target/ARM/ARMFrameLowering.cpp
index 4eafd82af4c..a52e49780e2 100644
--- a/llvm/lib/Target/ARM/ARMFrameLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMFrameLowering.cpp
@@ -43,6 +43,14 @@ ARMFrameLowering::ARMFrameLowering(const ARMSubtarget &sti)
     : TargetFrameLowering(StackGrowsDown, sti.getStackAlignment(), 0, 4),
       STI(sti) {}
 
+bool ARMFrameLowering::noFramePointerElim(const MachineFunction &MF) const {
+  // iOS always has a FP for backtracking, force other targets to keep their FP
+  // when doing FastISel. The emitted code is currently superior, and in cases
+  // like test-suite's lencod FastISel isn't quite correct when FP is eliminated.
+  return TargetFrameLowering::noFramePointerElim(MF) ||
+         MF.getSubtarget<ARMSubtarget>().useFastISel();
+}
+
 /// hasFP - Return true if the specified function should have a dedicated frame
 /// pointer register.  This is true if the function has variable sized allocas
 /// or if frame pointer elimination is disabled.
diff --git a/llvm/lib/Target/ARM/ARMFrameLowering.h b/llvm/lib/Target/ARM/ARMFrameLowering.h
index ff3425795ae..d763d17a506 100644
--- a/llvm/lib/Target/ARM/ARMFrameLowering.h
+++ b/llvm/lib/Target/ARM/ARMFrameLowering.h
@@ -43,6 +43,8 @@ public:
                                   const std::vector<CalleeSavedInfo> &CSI,
                                   const TargetRegisterInfo *TRI) const override;
 
+  bool noFramePointerElim(const MachineFunction &MF) const override;
+
   bool hasFP(const MachineFunction &MF) const override;
   bool hasReservedCallFrame(const MachineFunction &MF) const override;
   bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.cpp b/llvm/lib/Target/ARM/ARMSubtarget.cpp
index 89aab260366..008aeffd171 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.cpp
+++ b/llvm/lib/Target/ARM/ARMSubtarget.cpp
@@ -353,3 +353,10 @@ bool ARMSubtarget::useMovt(const MachineFunction &MF) const {
   return UseMovt && (isTargetWindows() ||
                      !MF.getFunction()->hasFnAttribute(Attribute::MinSize));
 }
+
+bool ARMSubtarget::useFastISel() const {
+  // Thumb2 support on iOS; ARM support on iOS, Linux and NaCl.
+  return TM.Options.EnableFastISel &&
+         ((isTargetMachO() && !isThumb1Only()) ||
+          (isTargetLinux() && !isThumb()) || (isTargetNaCl() && !isThumb()));
+}
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.h b/llvm/lib/Target/ARM/ARMSubtarget.h
index ed1c6a0fc64..77ceb081db1 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.h
+++ b/llvm/lib/Target/ARM/ARMSubtarget.h
@@ -450,6 +450,8 @@ public:
   /// symbol.
   bool GVIsIndirectSymbol(const GlobalValue *GV, Reloc::Model RelocM) const;
 
+  /// True if fast-isel is used.
+  bool useFastISel() const;
 };
 } // End llvm namespace
 
diff --git a/llvm/lib/Target/TargetMachine.cpp b/llvm/lib/Target/TargetMachine.cpp
index 0523f04bee0..36875b47ab6 100644
--- a/llvm/lib/Target/TargetMachine.cpp
+++ b/llvm/lib/Target/TargetMachine.cpp
@@ -66,7 +66,6 @@ void TargetMachine::resetTargetOptions(const Function &F) const {
       Options.X = (F.getFnAttribute(Y).getValueAsString() == "true");          \
   } while (0)
 
-  RESET_OPTION(NoFramePointerElim, "no-frame-pointer-elim");
   RESET_OPTION(LessPreciseFPMADOption, "less-precise-fpmad");
   RESET_OPTION(UnsafeFPMath, "unsafe-fp-math");
   RESET_OPTION(NoInfsFPMath, "no-infs-fp-math");