[PATCH] D109112: [darwin/x86] Model cxx_fast_tlscc as not preserving r11

[Nico Weber via Phabricator via llvm-commits]

thakis created this revision.
thakis added a reviewer: rjmccall.
Herald added subscribers: pengfei, hiraditya.
thakis requested review of this revision.
Herald added a project: LLVM.

If a TLV stub is called from a dylib, dyld_stub_binder will
clobber r11.

Fixes PR51703.


https://reviews.llvm.org/D109112

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


Index: llvm/test/CodeGen/X86/cxx_tlscc64.ll
===================================================================
--- llvm/test/CodeGen/X86/cxx_tlscc64.ll
+++ llvm/test/CodeGen/X86/cxx_tlscc64.ll
@@ -18,7 +18,6 @@
 
 ; Every GPR should be saved - except rdi, rax, and rsp
 ; CHECK-LABEL: _ZTW2sg
-; CHECK-NOT: pushq %r11
 ; CHECK-NOT: pushq %r10
 ; CHECK-NOT: pushq %r9
 ; CHECK-NOT: pushq %r8
@@ -38,10 +37,8 @@
 ; CHECK-NOT: popq %r8
 ; CHECK-NOT: popq %r9
 ; CHECK-NOT: popq %r10
-; CHECK-NOT: popq %r11
 
 ; CHECK-O0-LABEL: _ZTW2sg
-; CHECK-O0: pushq %r11
 ; CHECK-O0: pushq %r10
 ; CHECK-O0: pushq %r9
 ; CHECK-O0: pushq %r8
@@ -59,7 +56,6 @@
 ; CHECK-O0: popq %r8
 ; CHECK-O0: popq %r9
 ; CHECK-O0: popq %r10
-; CHECK-O0: popq %r11
 define cxx_fast_tlscc nonnull %struct.S* @_ZTW2sg() nounwind {
   %.b.i = load i1, i1* @__tls_guard, align 1
   br i1 %.b.i, label %__tls_init.exit, label %init.i
@@ -75,7 +71,6 @@
 }
 
 ; CHECK-LABEL: _ZTW4sum1
-; CHECK-NOT: pushq %r11
 ; CHECK-NOT: pushq %r10
 ; CHECK-NOT: pushq %r9
 ; CHECK-NOT: pushq %r8
@@ -85,7 +80,6 @@
 ; CHECK-NOT: pushq %rbx
 ; CHECK: callq
 ; CHECK-O0-LABEL: _ZTW4sum1
-; CHECK-O0-NOT: pushq %r11
 ; CHECK-O0-NOT: pushq %r10
 ; CHECK-O0-NOT: pushq %r9
 ; CHECK-O0-NOT: pushq %r8
@@ -93,7 +87,6 @@
 ; CHECK-O0-NOT: pushq %rdx
 ; CHECK-O0-NOT: pushq %rcx
 ; CHECK-O0-NOT: pushq %rbx
-; CHECK-O0-NOT: movq %r11
 ; CHECK-O0-NOT: movq %r10
 ; CHECK-O0-NOT: movq %r9
 ; CHECK-O0-NOT: movq %r8
@@ -117,7 +110,6 @@
 
 ; Make sure at O0, we don't generate spilling/reloading of the CSRs.
 ; CHECK-O0-LABEL: tls_test2
-; CHECK-O0-NOT: pushq %r11
 ; CHECK-O0-NOT: pushq %r10
 ; CHECK-O0-NOT: pushq %r9
 ; CHECK-O0-NOT: pushq %r8
@@ -129,7 +121,6 @@
 ; CHECK-O0-NOT: popq %r8
 ; CHECK-O0-NOT: popq %r9
 ; CHECK-O0-NOT: popq %r10
-; CHECK-O0-NOT: popq %r11
 ; CHECK-O0: ret
 %class.C = type { i32 }
 @tC = internal thread_local global %class.C zeroinitializer, align 4
@@ -154,7 +145,6 @@
 @ssp_var = internal thread_local global i8 0, align 1
 
 ; CHECK-LABEL: test_ssp
-; CHECK-NOT: pushq %r11
 ; CHECK-NOT: pushq %r10
 ; CHECK-NOT: pushq %r9
 ; CHECK-NOT: pushq %r8
Index: llvm/lib/Target/X86/X86CallingConv.td
===================================================================
--- llvm/lib/Target/X86/X86CallingConv.td
+++ llvm/lib/Target/X86/X86CallingConv.td
@@ -1116,10 +1116,10 @@
 def CSR_Win64_SwiftTail : CalleeSavedRegs<(sub CSR_Win64, R13, R14)>;
 
 // The function used by Darwin to obtain the address of a thread-local variable
-// uses rdi to pass a single parameter and rax for the return value. All other
-// GPRs are preserved.
+// uses rdi to pass a single parameter and rax for the return value. The
+// dynamic linker can clobber r11. All other GPRs are preserved.
 def CSR_64_TLS_Darwin : CalleeSavedRegs<(add CSR_64, RCX, RDX, RSI,
-                                             R8, R9, R10, R11)>;
+                                             R8, R9, R10)>;
 
 // CSRs that are handled by prologue, epilogue.
 def CSR_64_CXX_TLS_Darwin_PE : CalleeSavedRegs<(add RBP)>;


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