Support for emitting inline stack probes

For CoreCLR on Windows, stack probes must be emitted as inline sequences that probe successive stack pages
between the current stack limit and the desired new stack pointer location. This implements support for
the inline expansion on x64.

For in-body alloca probes, expansion is done during instruction lowering. For prolog probes, a stub call
is initially emitted during prolog creation, and expanded after epilog generation, to avoid complications
that arise when introducing new machine basic blocks during prolog and epilog creation.

Added a new test case, modified an existing one to exclude non-x64 coreclr (for now).

Add test case

Fix tests

llvm-svn: 252578

1 files changed, 36 insertions, 4 deletions

diff --git a/llvm/lib/Target/X86/X86FrameLowering.h b/llvm/lib/Target/X86/X86FrameLowering.h
index 6975d250296..db32be12924 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.h
+++ b/llvm/lib/Target/X86/X86FrameLowering.h
@@ -47,11 +47,17 @@ public:
 
   unsigned StackPtr;
 
-  /// Emit a call to the target's stack probe function. This is required for all
+  /// Emit target stack probe code. This is required for all
   /// large stack allocations on Windows. The caller is required to materialize
-  /// the number of bytes to probe in RAX/EAX.
-  void emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
-                          MachineBasicBlock::iterator MBBI, DebugLoc DL) const;
+  /// the number of bytes to probe in RAX/EAX. Returns instruction just
+  /// after the expansion.
+  MachineInstr *emitStackProbe(MachineFunction &MF, MachineBasicBlock &MBB,
+                               MachineBasicBlock::iterator MBBI, DebugLoc DL,
+                               bool InProlog) const;
+
+  /// Replace a StackProbe inline-stub with the actual probe code inline.
+  void inlineStackProbe(MachineFunction &MF,
+                        MachineBasicBlock &PrologMBB) const override;
 
   void emitCalleeSavedFrameMoves(MachineBasicBlock &MBB,
                                  MachineBasicBlock::iterator MBBI,
@@ -125,6 +131,15 @@ public:
   /// \p MBB will be correctly handled by the target.
   bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
 
+  /// convertArgMovsToPushes - This method tries to convert a call sequence
+  /// that uses sub and mov instructions to put the argument onto the stack
+  /// into a series of pushes.
+  /// Returns true if the transformation succeeded, false if not.
+  bool convertArgMovsToPushes(MachineFunction &MF, 
+                              MachineBasicBlock &MBB,
+                              MachineBasicBlock::iterator I, 
+                              uint64_t Amount) const;
+
   /// Wraps up getting a CFI index and building a MachineInstr for it.
   void BuildCFI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
                 DebugLoc DL, MCCFIInstruction CFIInst) const;
@@ -139,6 +154,23 @@ public:
 private:
   uint64_t calculateMaxStackAlign(const MachineFunction &MF) const;
 
+  /// Emit target stack probe as a call to a helper function
+  MachineInstr *emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
+                                   MachineBasicBlock::iterator MBBI,
+                                   DebugLoc DL, bool InProlog) const;
+
+  /// Emit target stack probe as an inline sequence.
+  MachineInstr *emitStackProbeInline(MachineFunction &MF,
+                                     MachineBasicBlock &MBB,
+                                     MachineBasicBlock::iterator MBBI,
+                                     DebugLoc DL, bool InProlog) const;
+
+  /// Emit a stub to later inline the target stack probe.
+  MachineInstr *emitStackProbeInlineStub(MachineFunction &MF,
+                                         MachineBasicBlock &MBB,
+                                         MachineBasicBlock::iterator MBBI,
+                                         DebugLoc DL, bool InProlog) const;
+
   /// Aligns the stack pointer by ANDing it with -MaxAlign.
   void BuildStackAlignAND(MachineBasicBlock &MBB,
                           MachineBasicBlock::iterator MBBI, DebugLoc DL,