[stack protector] Fix a potential security bug in stack protector where the

address of the stack guard was being spilled to the stack.

Previously the address of the stack guard would get spilled to the stack if it
was impossible to keep it in a register. This patch introduces a new target
independent node and pseudo instruction which gets expanded post-RA to a
sequence of instructions that load the stack guard value. Register allocator
can now just remat the value when it can't keep it in a register. 

<rdar://problem/12475629>

llvm-svn: 213967

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/utils/TableGen/CodeGenTarget.cpp b/llvm/utils/TableGen/CodeGenTarget.cpp
index d1b57118e0e..597da68dcbc 100644
--- a/llvm/utils/TableGen/CodeGenTarget.cpp
+++ b/llvm/utils/TableGen/CodeGenTarget.cpp
@@ -301,7 +301,8 @@ void CodeGenTarget::ComputeInstrsByEnum() const {
       "GC_LABEL",     "KILL",          "EXTRACT_SUBREG",   "INSERT_SUBREG",
       "IMPLICIT_DEF", "SUBREG_TO_REG", "COPY_TO_REGCLASS", "DBG_VALUE",
       "REG_SEQUENCE", "COPY",          "BUNDLE",           "LIFETIME_START",
-      "LIFETIME_END", "STACKMAP",      "PATCHPOINT",       nullptr};
+      "LIFETIME_END", "STACKMAP",      "PATCHPOINT",       "LOAD_STACK_GUARD",
+      nullptr};
   const DenseMap<const Record*, CodeGenInstruction*> &Insts = getInstructions();
   for (const char *const *p = FixedInstrs; *p; ++p) {
     const CodeGenInstruction *Instr = GetInstByName(*p, Insts, Records);