From 586272d67ca0cd91e49aa0f03298cc1294128385 Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Thu, 11 Aug 2011 01:48:05 +0000
Subject: [PATCH] Fix X86TargetLowering::LowerExternalSymbol so that it
 actually works in non-trivial cases.  This hasn't been an issue before
 because the function isn't normally called (but apparently is used to
 generate a tail-call to sin() on ELF x86-32 with PIC and SSE2).

Fixes PR9693.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137292 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp | 21 ++++++++++++++++-----
 test/CodeGen/X86/tail-call-got.ll  | 24 ++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 5 deletions(-)
 create mode 100644 test/CodeGen/X86/tail-call-got.ll

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index d709bc09da9..217a7bcf530 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -6758,12 +6758,17 @@ X86TargetLowering::LowerExternalSymbol(SDValue Op, SelectionDAG &DAG) const {
   CodeModel::Model M = getTargetMachine().getCodeModel();
 
   if (Subtarget->isPICStyleRIPRel() &&
-      (M == CodeModel::Small || M == CodeModel::Kernel))
+      (M == CodeModel::Small || M == CodeModel::Kernel)) {
+    if (Subtarget->isTargetDarwin() || Subtarget->isTargetELF())
+      OpFlag = X86II::MO_GOTPCREL;
     WrapperKind = X86ISD::WrapperRIP;
-  else if (Subtarget->isPICStyleGOT())
-    OpFlag = X86II::MO_GOTOFF;
-  else if (Subtarget->isPICStyleStubPIC())
-    OpFlag = X86II::MO_PIC_BASE_OFFSET;
+  } else if (Subtarget->isPICStyleGOT()) {
+    OpFlag = X86II::MO_GOT;
+  } else if (Subtarget->isPICStyleStubPIC()) {
+    OpFlag = X86II::MO_DARWIN_NONLAZY_PIC_BASE;
+  } else if (Subtarget->isPICStyleStubNoDynamic()) {
+    OpFlag = X86II::MO_DARWIN_NONLAZY;
+  }
 
   SDValue Result = DAG.getTargetExternalSymbol(Sym, getPointerTy(), OpFlag);
 
@@ -6780,6 +6785,12 @@ X86TargetLowering::LowerExternalSymbol(SDValue Op, SelectionDAG &DAG) const {
                          Result);
   }
 
+  // For symbols that require a load from a stub to get the address, emit the
+  // load.
+  if (isGlobalStubReference(OpFlag))
+    Result = DAG.getLoad(getPointerTy(), DL, DAG.getEntryNode(), Result,
+                         MachinePointerInfo::getGOT(), false, false, 0);
+
   return Result;
 }
 
diff --git a/test/CodeGen/X86/tail-call-got.ll b/test/CodeGen/X86/tail-call-got.ll
new file mode 100644
index 00000000000..8910ee272db
--- /dev/null
+++ b/test/CodeGen/X86/tail-call-got.ll
@@ -0,0 +1,24 @@
+; RUN: llc < %s -relocation-model=pic | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32"
+target triple = "i386-unknown-freebsd9.0"
+
+define double @test1(double %x) nounwind readnone {
+; CHECK: test1:
+; CHECK: movl foo@GOT
+; CHECK-NEXT: jmpl
+  %1 = tail call double @foo(double %x) nounwind readnone
+  ret double %1
+}
+
+declare double @foo(double) readnone
+
+define double @test2(double %x) nounwind readnone {
+; CHECK: test2:
+; CHECK: movl sin@GOT
+; CHECK-NEXT: jmpl
+  %1 = tail call double @sin(double %x) nounwind readnone
+  ret double %1
+}
+
+declare double @sin(double) readnone