[Alignment][NFC] Deprecate dead code from CallingConvLower.h

[gchatelet]

Summary

This is a followup on D81196.

[courbet]

Shouldn't this undergo a deprecation cycle ? This is a public header.

[gchatelet]

Deprecate functions and amend commit message

[ctetreau]

It looks like this function isn't actually dead code. I'm getting a ton of deprecation warnings about it on my master build, and this build bot run from one commit after yours that fixed the build failure has a bunch: http://lab.llvm.org:8011/builders/llvm-clang-x86_64-win-fast/builds/17308

I thought the build bots built with -werror? How are these builds passing?

[gchatelet]

In D81362#2080266, @ctetreau wrote:

It looks like this function isn't actually dead code. I'm getting a ton of deprecation warnings about it on my master build, and this build bot run from one commit after yours that fixed the build failure has a bunch: http://lab.llvm.org:8011/builders/llvm-clang-x86_64-win-fast/builds/17308

I thought the build bots built with -werror? How are these builds passing?

Thx for the heads up. I fixed it in rG49dd8e79913cc10676902fd2033a090758cf9b90.

As for the bots, there's a difference in how the deprecated attribute is treated between GCC/Clang and MSVC. For MSVC the warning triggers even if the faulty call is inside a deprecated method itself, it's not the case for Clang/GCC, so depending on which bot is running it triggers an error... or not.

[ctetreau]

For MSVC the warning triggers even if the faulty call is inside a deprecated method itself

Wow, really? Eww...

Either way, thanks for taking a look!

llvm/include/llvm/CodeGen/CallingConvLower.h

unsigned AllocateStack(unsigned Size, Align Alignment) {
     unsigned Result = StackOffset;
     StackOffset += Size;
     MaxStackArgAlign = std::max(Alignment, MaxStackArgAlign);
     ensureMaxAlignment(Alignment);
     return Result;
   }
 
   // FIXME: Deprecate this function when transition to Align is over.
-  unsigned AllocateStack(unsigned Size, unsigned Alignment) {
+  LLVM_ATTRIBUTE_DEPRECATED(unsigned AllocateStack(unsigned Size,
+                                                   unsigned Alignment),
+                            "Use the version that takes Align instead.") {
     return AllocateStack(Size, Align(Alignment));
   }
 
   void ensureMaxAlignment(Align Alignment) {
     if (!AnalyzingMustTailForwardedRegs)
       MF.getFrameInfo().ensureMaxAlignment(Alignment);
   }
 
   /// Version of AllocateStack with extra register to be shadowed.
-  unsigned AllocateStack(unsigned Size, unsigned Align, unsigned ShadowReg) {
+  LLVM_ATTRIBUTE_DEPRECATED(unsigned AllocateStack(unsigned Size,
+                                                   unsigned Align,
+                                                   unsigned ShadowReg),
+                            "Use the version that takes Align instead.") {
     MarkAllocated(ShadowReg);
     return AllocateStack(Size, Align);
   }
 
   /// Version of AllocateStack with list of extra registers to be shadowed.
   /// Note that, unlike AllocateReg, this shadows ALL of the shadow registers.
   unsigned AllocateStack(unsigned Size, Align Alignment,
                          ArrayRef<MCPhysReg> ShadowRegs) {

llvm/lib/CodeGen/CallingConvLower.cpp

void CCState::HandleByVal(unsigned ValNo, MVT ValVT, MVT LocVT,
   unsigned Size  = ArgFlags.getByValSize();
   if (MinSize > (int)Size)
     Size = MinSize;
   if (MinAlign > Alignment)
     Alignment = MinAlign;
   ensureMaxAlignment(Alignment);
   MF.getSubtarget().getTargetLowering()->HandleByVal(this, Size, Alignment);
   Size = unsigned(alignTo(Size, MinAlign));
-  unsigned Offset = AllocateStack(Size, Alignment.value());
+  unsigned Offset = AllocateStack(Size, Alignment);
   addLoc(CCValAssign::getMem(ValNo, ValVT, Offset, LocVT, LocInfo));
 }
 
 /// Mark a register and all of its aliases as allocated.
 void CCState::MarkAllocated(MCPhysReg Reg) {
   for (MCRegAliasIterator AI(Reg, &TRI, true); AI.isValid(); ++AI)
     UsedRegs[*AI / 32] |= 1 << (*AI & 31);
 }