[llvm] r225617 - [PowerPC] Fix calls to non-function objects
Hal Finkel
hfinkel at anl.gov
Sun Jan 11 20:34:48 PST 2015
Author: hfinkel
Date: Sun Jan 11 22:34:47 2015
New Revision: 225617
URL: http://llvm.org/viewvc/llvm-project?rev=225617&view=rev
Log:
[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.
Added:
llvm/trunk/test/CodeGen/PowerPC/ppc64-nonfunc-calls.ll
Modified:
llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
Modified: llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp?rev=225617&r1=225616&r2=225617&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp Sun Jan 11 22:34:47 2015
@@ -3573,6 +3573,20 @@ void PrepareTailCall(SelectionDAG &DAG,
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 @@ unsigned PrepareCall(SelectionDAG &DAG,
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 @@ PPCTargetLowering::LowerCall_64SVR4(SDVa
// 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 @@ PPCTargetLowering::LowerCall_Darwin(SDVa
// 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));
Added: llvm/trunk/test/CodeGen/PowerPC/ppc64-nonfunc-calls.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/ppc64-nonfunc-calls.ll?rev=225617&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/ppc64-nonfunc-calls.ll (added)
+++ llvm/trunk/test/CodeGen/PowerPC/ppc64-nonfunc-calls.ll Sun Jan 11 22:34:47 2015
@@ -0,0 +1,69 @@
+; RUN: llc -mcpu=ppc64 < %s | FileCheck %s
+target datalayout = "E-m:e-i64:64-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+%struct.cd = type { i64, i64, i64 }
+
+ at something = global [33 x i8] c"this is not really code, but...\0A\00", align 1
+ at tls_something = thread_local global %struct.cd zeroinitializer, align 8
+ at extern_something = external global %struct.cd
+
+; Function Attrs: nounwind
+define void @foo() #0 {
+entry:
+ tail call void bitcast ([33 x i8]* @something to void ()*)() #0
+ ret void
+
+; CHECK-LABEL: @foo
+; CHECK-DAG: addis [[REG1:[0-9]+]], 2, something at toc@ha
+; CHECK-DAG: std 2, 40(1)
+; CHECK-DAG: addi [[REG3:[0-9]+]], [[REG1]], something at toc@l
+; CHECK-DAG: ld [[REG2:[0-9]+]], 0([[REG3]])
+; CHECK-DAG: ld 11, 16([[REG3]])
+; CHECK-DAG: ld 2, 8([[REG3]])
+; CHECK-DAG: mtctr [[REG2]]
+; CHECK: bctrl
+; CHECK: ld 2, 40(1)
+; CHECK: blr
+}
+
+; Function Attrs: nounwind
+define void @bar() #0 {
+entry:
+ tail call void bitcast (%struct.cd* @tls_something to void ()*)() #0
+ ret void
+
+; CHECK-LABEL: @bar
+; CHECK-DAG: addis [[REG1:[0-9]+]], 13, tls_something at tprel@ha
+; CHECK-DAG: std 2, 40(1)
+; CHECK-DAG: addi [[REG3:[0-9]+]], [[REG1]], tls_something at tprel@l
+; CHECK-DAG: ld [[REG2:[0-9]+]], 0([[REG3]])
+; CHECK-DAG: ld 11, 16([[REG3]])
+; CHECK-DAG: ld 2, 8([[REG3]])
+; CHECK-DAG: mtctr [[REG2]]
+; CHECK: bctrl
+; CHECK: ld 2, 40(1)
+; CHECK: blr
+}
+
+; Function Attrs: nounwind
+define void @ext() #0 {
+entry:
+ tail call void bitcast (%struct.cd* @extern_something to void ()*)() #0
+ ret void
+
+; CHECK-LABEL: @ext
+; CHECK-DAG: addis [[REG1:[0-9]+]], 2, [[NAME:[._A-Za-z0-9]+]]@toc at ha
+; CHECK-DAG: std 2, 40(1)
+; CHECK-DAG: ld [[REG3:[0-9]+]], [[NAME]]@toc at l(3)
+; CHECK-DAG: ld [[REG2:[0-9]+]], 0([[REG3]])
+; CHECK-DAG: ld 11, 16([[REG3]])
+; CHECK-DAG: ld 2, 8([[REG3]])
+; CHECK-DAG: mtctr [[REG2]]
+; CHECK: bctrl
+; CHECK: ld 2, 40(1)
+; CHECK: blr
+}
+
+attributes #0 = { nounwind }
+
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