Last round of changes for ARM tail calls.
Not turning them on yet.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106295 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 5ec995f..50258c6 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -1101,7 +1101,7 @@
}
} else if (VA.isRegLoc()) {
RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
- } else {
+ } else if (!IsSibCall) {
assert(VA.isMemLoc());
MemOpChains.push_back(LowerMemOpCallTo(Chain, StackPtr, Arg,
@@ -1357,12 +1357,6 @@
// Look for obvious safe cases to perform tail call optimization that do not
// require ABI changes. This is what gcc calls sibcall.
- // Can't do sibcall if stack needs to be dynamically re-aligned. PEI needs to
- // emit a special epilogue.
- // Not sure yet if this is true on ARM.
-//?? if (RegInfo->needsStackRealignment(MF))
-//?? return false;
-
// Do not sibcall optimize vararg calls unless the call site is not passing
// any arguments.
if (isVarArg && !Outs.empty())
@@ -1373,6 +1367,19 @@
if (isCalleeStructRet || isCallerStructRet)
return false;
+ // On Thumb, for the moment, we can only do this to functions defined in this
+ // compilation, or to indirect calls. A Thumb B to an ARM function is not
+ // easily fixed up in the linker, unlike BL.
+ if (Subtarget->isThumb()) {
+ if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
+ const GlobalValue *GV = G->getGlobal();
+ if (GV->isDeclaration() || GV->isWeakForLinker())
+ return false;
+ } else if (isa<ExternalSymbolSDNode>(Callee)) {
+ return false;
+ }
+ }
+
// If the calling conventions do not match, then we'd better make sure the
// results are returned in the same way as what the caller expects.
if (!CCMatch) {
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 052104d..d95137a 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -1049,7 +1049,7 @@
"@TC_RETURN","\t$dst", []>, Requires<[IsDarwin]>;
def TAILJMPd : ABXI<0b1010, (outs), (ins brtarget:$dst, variable_ops),
- IIC_Br, "b\t$dst @ TAILCALL",
+ IIC_Br, "b.w\t$dst @ TAILCALL",
[]>, Requires<[IsDarwin]>;
def TAILJMPr : AXI<(outs), (ins tcGPR:$dst, variable_ops),
@@ -1084,7 +1084,7 @@
"@TC_RETURN","\t$dst", []>, Requires<[IsNotDarwin]>;
def TAILJMPdND : ABXI<0b1010, (outs), (ins brtarget:$dst, variable_ops),
- IIC_Br, "b\t$dst @ TAILCALL",
+ IIC_Br, "b.w\t$dst @ TAILCALL",
[]>, Requires<[IsNotDarwin]>;
def TAILJMPrND : AXI<(outs), (ins tGPR:$dst, variable_ops),