[PowerPC] Fix calls to non-function objects
Looking at r225438 inspired me to see how the PowerPC backend handled the
situation (calling a bitcasted TLS global), and it turns out we also produced
an error (cannot select ...). What it means to "call" something that is not a
function is implementation and platform specific, but in the name of doing
something (besides crashing), this makes sure we do what GCC does (treat all
such calls as calls through a function pointer -- meaning that the pointer is
assumed, as is the convention on PPC, to point to a function descriptor
structure holding the actual code address along with the function's TOC pointer
and environment pointer). As GCC does, we now do the same for calling regular
(non-TLS) non-function globals too.
I'm not sure whether this is the most useful way to define the behavior, but at
least we won't be alone.
llvm-svn: 225617
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index e93c781..30f08d0 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -3573,6 +3573,20 @@
InFlag = Chain.getValue(1);
}
+// Is this global address that of a function that can be called by name? (as
+// opposed to something that must hold a descriptor for an indirect call).
+static bool isFunctionGlobalAddress(SDValue Callee) {
+ if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
+ if (Callee.getOpcode() == ISD::GlobalTLSAddress ||
+ Callee.getOpcode() == ISD::TargetGlobalTLSAddress)
+ return false;
+
+ return G->getGlobal()->getType()->getElementType()->isFunctionTy();
+ }
+
+ return false;
+}
+
static
unsigned PrepareCall(SelectionDAG &DAG, SDValue &Callee, SDValue &InFlag,
SDValue &Chain, SDLoc dl, int SPDiff, bool isTailCall,
@@ -3598,7 +3612,10 @@
needIndirectCall = false;
}
- if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
+ if (isFunctionGlobalAddress(Callee)) {
+ GlobalAddressSDNode *G = cast<GlobalAddressSDNode>(Callee);
+ // A call to a TLS address is actually an indirect call to a
+ // thread-specific pointer.
unsigned OpFlags = 0;
if ((DAG.getTarget().getRelocationModel() != Reloc::Static &&
(Subtarget.getTargetTriple().isMacOSX() &&
@@ -4649,8 +4666,8 @@
// See PrepareCall() for more information about calls through function
// pointers in the 64-bit SVR4 ABI.
if (!isTailCall &&
- !dyn_cast<GlobalAddressSDNode>(Callee) &&
- !dyn_cast<ExternalSymbolSDNode>(Callee)) {
+ !isFunctionGlobalAddress(Callee) &&
+ !isa<ExternalSymbolSDNode>(Callee)) {
// Load r2 into a virtual register and store it to the TOC save area.
SDValue Val = DAG.getCopyFromReg(Chain, dl, PPC::X2, MVT::i64);
// TOC save area offset.
@@ -5053,8 +5070,8 @@
// not mean the MTCTR instruction must use R12; it's easier to model this as
// an extra parameter, so do that.
if (!isTailCall &&
- !dyn_cast<GlobalAddressSDNode>(Callee) &&
- !dyn_cast<ExternalSymbolSDNode>(Callee) &&
+ !isFunctionGlobalAddress(Callee) &&
+ !isa<ExternalSymbolSDNode>(Callee) &&
!isBLACompatibleAddress(Callee, DAG))
RegsToPass.push_back(std::make_pair((unsigned)(isPPC64 ? PPC::X12 :
PPC::R12), Callee));