[llvm] r257997 - CXX_FAST_TLS calling convention: fix issue on x86-64.

[Manman Ren via llvm-commits]

Author: mren
Date: Sat Jan 16 10:39:46 2016
New Revision: 257997

URL: http://llvm.org/viewvc/llvm-project?rev=257997&view=rev
Log:
CXX_FAST_TLS calling convention: fix issue on x86-64.

%RBP can't be handled explicitly. We generate the following code:
    pushq %rbp
    movq  %rsp, %rbp
    ...
    movq  %rbx, (%rbp)  ## 8-byte Spill
where %rbp will be overwritten by the spilled value.

The fix is to let PEI handle %RBP.
PR26136

Modified:
    llvm/trunk/lib/Target/X86/X86CallingConv.td
    llvm/trunk/test/CodeGen/X86/cxx_tlscc64.ll

Modified: llvm/trunk/lib/Target/X86/X86CallingConv.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86CallingConv.td?rev=257997&r1=257996&r2=257997&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86CallingConv.td (original)
+++ llvm/trunk/lib/Target/X86/X86CallingConv.td Sat Jan 16 10:39:46 2016
@@ -832,10 +832,10 @@ def CSR_64_TLS_Darwin : CalleeSavedRegs<
                                              R8, R9, R10, R11)>;
 
 // CSRs that are handled by prologue, epilogue.
-def CSR_64_CXX_TLS_Darwin_PE : CalleeSavedRegs<(add)>;
+def CSR_64_CXX_TLS_Darwin_PE : CalleeSavedRegs<(add RBP)>;
 
 // CSRs that are handled explicitly via copies.
-def CSR_64_CXX_TLS_Darwin_ViaCopy : CalleeSavedRegs<(add CSR_64_TLS_Darwin)>;
+def CSR_64_CXX_TLS_Darwin_ViaCopy : CalleeSavedRegs<(sub CSR_64_TLS_Darwin, RBP)>;
 
 // All GPRs - except r11
 def CSR_64_RT_MostRegs : CalleeSavedRegs<(add CSR_64, RAX, RCX, RDX, RSI, RDI,

Modified: llvm/trunk/test/CodeGen/X86/cxx_tlscc64.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/cxx_tlscc64.ll?rev=257997&r1=257996&r2=257997&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/cxx_tlscc64.ll (original)
+++ llvm/trunk/test/CodeGen/X86/cxx_tlscc64.ll Sat Jan 16 10:39:46 2016
@@ -4,6 +4,7 @@
 ; tricks similar to AArch64 fast TLS calling convention (r255821).
 ; Applying tricks on x86-64 similar to r255821.
 ; RUN: llc < %s -mtriple=x86_64-apple-darwin -enable-shrink-wrap=true | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-apple-darwin -O0 | FileCheck %s --check-prefix=CHECK-O0
 %struct.S = type { i8 }
 
 @sg = internal thread_local global %struct.S zeroinitializer, align 1
@@ -65,3 +66,14 @@ __tls_init.exit:
 define cxx_fast_tlscc nonnull i32* @_ZTW4sum1() nounwind {
   ret i32* @sum1
 }
+
+; Make sure at O0 we don't overwrite RBP.
+; CHECK-O0-LABEL: _ZTW4sum2
+; CHECK-O0: pushq %rbp
+; CHECK-O0: movq %rsp, %rbp
+; CHECK-O0-NOT: movq %r{{.*}}, (%rbp) 
+define cxx_fast_tlscc i32* @_ZTW4sum2() #0 {
+  ret i32* @sum1
+}
+
+attributes #0 = { nounwind "no-frame-pointer-elim"="true" }