Add call sequence start and end for __tls_get_addr

This is a fix for bug http://llvm.org/bugs/show_bug.cgi?id=25839.

For a PIC TLS variable access in a function, prologue (mflr followed by std and
stdu) gets scheduled after a tls_get_addr call. tls_get_addr messed up LR but
no one saves/restores it.

Also added a test for save/restore clobbered registers during calling __tls_get_addr.

Patch by Tim Shen

llvm-svn: 257137

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCTLSDynamicCall.cpp b/llvm/lib/Target/PowerPC/PPCTLSDynamicCall.cpp
index 2dc0d825c80..a9d2e888f4b 100644
--- a/llvm/lib/Target/PowerPC/PPCTLSDynamicCall.cpp
+++ b/llvm/lib/Target/PowerPC/PPCTLSDynamicCall.cpp
@@ -99,6 +99,11 @@ protected:
           break;
         }
 
+        // Don't really need to save data to the stack - the clobbered
+        // registers are already saved when the SDNode (e.g. PPCaddiTlsgdLAddr)
+        // gets translated to the pseudo instruction (e.g. ADDItlsgdLADDR).
+        BuildMI(MBB, I, DL, TII->get(PPC::ADJCALLSTACKDOWN)).addImm(0);
+
         // Expand into two ops built prior to the existing instruction.
         MachineInstr *Addi = BuildMI(MBB, I, DL, TII->get(Opc1), GPR3)
           .addReg(InReg);
@@ -113,6 +118,8 @@ protected:
                               .addReg(GPR3));
         Call->addOperand(MI->getOperand(3));
 
+        BuildMI(MBB, I, DL, TII->get(PPC::ADJCALLSTACKUP)).addImm(0).addImm(0);
+
         BuildMI(MBB, I, DL, TII->get(TargetOpcode::COPY), OutReg)
           .addReg(GPR3);