Add a set of comments explaining why getSubtargetImpl() is deleted on these targets.

llvm-svn: 307999

4 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64TargetMachine.h b/llvm/lib/Target/AArch64/AArch64TargetMachine.h
index fefa7e26b79..85de02e859e 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetMachine.h
+++ b/llvm/lib/Target/AArch64/AArch64TargetMachine.h
@@ -36,6 +36,8 @@ public:
 
   ~AArch64TargetMachine() override;
   const AArch64Subtarget *getSubtargetImpl(const Function &F) const override;
+  // The no argument getSubtargetImpl, while it exists on some, targets is
+  // deprecated and should not be used.
   const AArch64Subtarget *getSubtargetImpl() const = delete;
 
   // Pass Pipeline Configuration
diff --git a/llvm/lib/Target/ARM/ARMTargetMachine.h b/llvm/lib/Target/ARM/ARMTargetMachine.h
index f41da3e8e22..22ce949367f 100644
--- a/llvm/lib/Target/ARM/ARMTargetMachine.h
+++ b/llvm/lib/Target/ARM/ARMTargetMachine.h
@@ -47,6 +47,8 @@ public:
   ~ARMBaseTargetMachine() override;
 
   const ARMSubtarget *getSubtargetImpl(const Function &F) const override;
+  // The no argument getSubtargetImpl, while it exists on some targets, is
+  // deprecated and should not be used.
   const ARMSubtarget *getSubtargetImpl() const = delete;
   bool isLittleEndian() const { return isLittle; }
 
diff --git a/llvm/lib/Target/PowerPC/PPCTargetMachine.h b/llvm/lib/Target/PowerPC/PPCTargetMachine.h
index 2dc3828334a..be705507b53 100644
--- a/llvm/lib/Target/PowerPC/PPCTargetMachine.h
+++ b/llvm/lib/Target/PowerPC/PPCTargetMachine.h
@@ -41,6 +41,8 @@ public:
   ~PPCTargetMachine() override;
 
   const PPCSubtarget *getSubtargetImpl(const Function &F) const override;
+  // The no argument getSubtargetImpl, while it exists on some targets, is
+  // deprecated and should not be used.
   const PPCSubtarget *getSubtargetImpl() const = delete;
 
   // Pass Pipeline Configuration
diff --git a/llvm/lib/Target/X86/X86TargetMachine.h b/llvm/lib/Target/X86/X86TargetMachine.h
index aaa6d58bd13..c16207973b3 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.h
+++ b/llvm/lib/Target/X86/X86TargetMachine.h
@@ -40,6 +40,8 @@ public:
   ~X86TargetMachine() override;
 
   const X86Subtarget *getSubtargetImpl(const Function &F) const override;
+  // The no argument getSubtargetImpl, while it exists on some targets, is
+  // deprecated and should not be used.
   const X86Subtarget *getSubtargetImpl() const = delete;
 
   TargetIRAnalysis getTargetIRAnalysis() override;