[llvm] r275135 - Teach FastISel about thiscall (and, hence, about callee-pop).

[Nico Weber via llvm-commits]

Author: nico
Date: Mon Jul 11 20:30:35 2016
New Revision: 275135

URL: http://llvm.org/viewvc/llvm-project?rev=275135&view=rev
Log:
Teach FastISel about thiscall (and, hence, about callee-pop).

http://reviews.llvm.org/D22115

Modified:
    llvm/trunk/lib/Target/X86/X86FastISel.cpp
    llvm/trunk/test/CodeGen/X86/fast-isel-x86.ll

Modified: llvm/trunk/lib/Target/X86/X86FastISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FastISel.cpp?rev=275135&r1=275134&r2=275135&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86FastISel.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86FastISel.cpp Mon Jul 11 20:30:35 2016
@@ -1151,14 +1151,15 @@ bool X86FastISel::X86SelectRet(const Ins
   if (CC != CallingConv::C &&
       CC != CallingConv::Fast &&
       CC != CallingConv::X86_FastCall &&
+      CC != CallingConv::X86_ThisCall &&
       CC != CallingConv::X86_64_SysV)
     return false;
 
   if (Subtarget->isCallingConvWin64(CC))
     return false;
 
-  // Don't handle popping bytes on return for now.
-  if (X86MFInfo->getBytesToPopOnReturn() != 0)
+  // Don't handle popping bytes if they don't fit the ret's immediate.
+  if (!isUInt<16>(X86MFInfo->getBytesToPopOnReturn()))
     return false;
 
   // fastcc with -tailcallopt is intended to provide a guaranteed
@@ -1261,9 +1262,15 @@ bool X86FastISel::X86SelectRet(const Ins
   }
 
   // Now emit the RET.
-  MachineInstrBuilder MIB =
-    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
-            TII.get(Subtarget->is64Bit() ? X86::RETQ : X86::RETL));
+  MachineInstrBuilder MIB;
+  if (X86MFInfo->getBytesToPopOnReturn()) {
+    MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
+                  TII.get(Subtarget->is64Bit() ? X86::RETIQ : X86::RETIL))
+              .addImm(X86MFInfo->getBytesToPopOnReturn());
+  } else {
+    MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
+                  TII.get(Subtarget->is64Bit() ? X86::RETQ : X86::RETL));
+  }
   for (unsigned i = 0, e = RetRegs.size(); i != e; ++i)
     MIB.addReg(RetRegs[i], RegState::Implicit);
   return true;

Modified: llvm/trunk/test/CodeGen/X86/fast-isel-x86.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/fast-isel-x86.ll?rev=275135&r1=275134&r2=275135&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/fast-isel-x86.ll (original)
+++ llvm/trunk/test/CodeGen/X86/fast-isel-x86.ll Mon Jul 11 20:30:35 2016
@@ -18,11 +18,29 @@ define void @test1({i32, i32, i32, i32}*
   ret void
 }
 
+; This should pop 8 bytes on return.
+; CHECK-LABEL: thiscallfun:
+; CHECK: retl $8
+define x86_thiscallcc void @thiscallfun(i32* %this, i32 %a, i32 %b) nounwind {
+  ret void
+}
+
+; Here, the callee pop doesn't fit the 16 bit immediate -- see x86-big-ret.ll
+; This checks that -fast-isel doesn't miscompile this.
+; CHECK-LABEL: thiscall_large:
+; CHECK:      popl %ecx
+; CHECK-NEXT: addl $65536, %esp
+; CHECK-NEXT: pushl %ecx
+; CHECK-NEXT: retl
+define x86_thiscallcc void @thiscall_large(i32* %this, [65533 x i8]* byval %b) nounwind {
+  ret void
+}
+
 ; Properly initialize the pic base.
 ; CHECK-LABEL: test2:
 ; CHECK-NOT: HHH
-; CHECK: call{{.*}}L2$pb
-; CHECK-NEXT: L2$pb:
+; CHECK: call{{.*}}L4$pb
+; CHECK-NEXT: L4$pb:
 ; CHECK-NEXT: pop
 ; CHECK: HHH
 ; CHECK: retl
@@ -75,7 +93,7 @@ entry:
 ; SDag-ISel's arg push:
 ; CHECK: movl %esp, [[REGISTER:%[a-z]+]]
 ; CHECK: movl $42, ([[REGISTER]])
-; CHECK: movl L_test5dllimport$non_lazy_ptr-L5$pb(%eax), %eax
+; CHECK: movl L_test5dllimport$non_lazy_ptr-L7$pb(%eax), %eax
 
 }
 declare dllimport i32 @test5dllimport(i32)