From 4377f132aec969234d7838fb133e546313df3b42 Mon Sep 17 00:00:00 2001
From: Quentin Colombet <qcolombet@apple.com>
Date: Wed, 6 Jan 2016 19:09:26 +0000
Subject: [PATCH] [X86] Correctly model TLS calls w.r.t. frame requirements.
 TLS calls need the stack frame to be properly set up and this implies that
 such calls need ADJUSTSTACK_xxx markers.

Fixes PR25820.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256959 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp      |  4 +++
 test/CodeGen/X86/cxx_tlscc64.ll         |  6 +++-
 test/CodeGen/X86/x86-shrink-wrapping.ll | 44 +++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 9b379aec403..b2b5bbf4b5b 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -12474,8 +12474,12 @@ X86TargetLowering::LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const {
     // location.
     SDValue Chain = DAG.getEntryNode();
     SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
+    Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(0, DL, true), DL);
     SDValue Args[] = { Chain, Offset };
     Chain = DAG.getNode(X86ISD::TLSCALL, DL, NodeTys, Args);
+    Chain =
+        DAG.getCALLSEQ_END(Chain, DAG.getIntPtrConstant(0, DL, true),
+                           DAG.getIntPtrConstant(0, DL, true), SDValue(), DL);
 
     // TLSCALL will be codegen'ed as call. Inform MFI that function has calls.
     MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
diff --git a/test/CodeGen/X86/cxx_tlscc64.ll b/test/CodeGen/X86/cxx_tlscc64.ll
index c229521cc9a..16e678a9222 100644
--- a/test/CodeGen/X86/cxx_tlscc64.ll
+++ b/test/CodeGen/X86/cxx_tlscc64.ll
@@ -1,5 +1,9 @@
 ; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
-; RUN: llc < %s -mtriple=x86_64-apple-darwin -enable-shrink-wrap=true | FileCheck --check-prefix=SHRINK %s
+; TLS function were wrongly model and after fixing that, shrink-wrapping
+; cannot help here. To achieve the expected lowering, we need to playing
+; tricks similar to AArch64 fast TLS calling convention (r255821).
+; Re-enable the following run line when 
+; _RUN_: llc < %s -mtriple=x86_64-apple-darwin -enable-shrink-wrap=true | FileCheck --check-prefix=SHRINK %s
 %struct.S = type { i8 }
 
 @sg = internal thread_local global %struct.S zeroinitializer, align 1
diff --git a/test/CodeGen/X86/x86-shrink-wrapping.ll b/test/CodeGen/X86/x86-shrink-wrapping.ll
index 34e56919468..b5a3174f10e 100644
--- a/test/CodeGen/X86/x86-shrink-wrapping.ll
+++ b/test/CodeGen/X86/x86-shrink-wrapping.ll
@@ -878,4 +878,48 @@ for.end:                                          ; preds = %for.cond.for.end_cr
 
 declare i32 @varfunc(i8* nocapture readonly)
 
+@sum1 = external hidden thread_local global i32, align 4
+
+
+; Function Attrs: nounwind
+; Make sure the TLS call used to access @sum1 happens after the prologue
+; and before the epilogue.
+; TLS calls used to be wrongly model and shrink-wrapping would have inserted
+; the prologue and epilogue just around the call to doSomething.
+; PR25820.
+;
+; CHECK-LABEL: tlsCall:
+; CHECK: pushq
+; CHECK: testb $1, %dil
+; CHECK: je [[ELSE_LABEL:LBB[0-9_]+]]
+;
+; master bb
+; CHECK: movq _sum1@TLVP(%rip), %rdi
+; CHECK-NEXT: callq *(%rdi)
+; CHECK: jmp [[EXIT_LABEL:LBB[0-9_]+]]
+;
+; [[ELSE_LABEL]]:
+; CHECK: callq _doSomething
+;
+; [[EXIT_LABEL]]:
+; CHECK: popq
+; CHECK-NEXT: retq
+define i32 @tlsCall(i1 %bool1, i32 %arg, i32* readonly dereferenceable(4) %sum1) #3 {
+entry:
+  br i1 %bool1, label %master, label %else
+
+master:
+  %tmp1 = load i32, i32* %sum1, align 4
+  store i32 %tmp1, i32* @sum1, align 4
+  br label %exit
+
+else:
+  %call = call i32 @doSomething(i32 0, i32* null)
+  br label %exit
+
+exit:
+  %res = phi i32 [ %arg, %master], [ %call, %else ]
+  ret i32 %res
+}
+
 attributes #3 = { nounwind }
-- 
2.34.1