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[Sparc] Correctly handle call to functions with ReturnsTwice attribute.

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In sparc, setjmp stores only the registers %fp, %sp, %i7 and %o7. longjmp restores
the stack, and the callee-saved registers (all local/in registers: %i0-%i7, %l0-%l7)
using the stored %fp and register windows. However, this does not guarantee that the longjmp
will restore the registers, as they were when the setjmp was called. This is because these
registers may be clobbered after returning from setjmp, but before calling longjmp.

This patch prevents the registers %i0-%i5, %l0-l7 to live across the setjmp call using the register mask.  



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190033 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Venkatraman Govindaraju
2013-09-05 05:32:16 +00:00
parent 2909c98019
commit 1b41835f02
5 changed files with 116 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
lib/Target/Sparc/SparcISelLowering.cpp
View File

@ -14,6 +14,7 @@
#include "SparcISelLowering.h"
#include "SparcMachineFunctionInfo.h"
#include "SparcRegisterInfo.h"
#include "SparcTargetMachine.h"
#include "MCTargetDesc/SparcBaseInfo.h"
#include "llvm/CodeGen/CallingConvLower.h"
@ -648,6 +649,27 @@ SparcTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
return LowerCall_32(CLI, InVals);
}
static bool hasReturnsTwiceAttr(SelectionDAG &DAG, SDValue Callee,
ImmutableCallSite *CS) {
if (CS)
return CS->hasFnAttr(Attribute::ReturnsTwice);
const Function *CalleeFn = 0;
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
CalleeFn = dyn_cast<Function>(G->getGlobal());
} else if (ExternalSymbolSDNode *E =
dyn_cast<ExternalSymbolSDNode>(Callee)) {
const Function *Fn = DAG.getMachineFunction().getFunction();
const Module *M = Fn->getParent();
const char *CalleeName = E->getSymbol();
CalleeFn = M->getFunction(CalleeName);
}
if (!CalleeFn)
return false;
return CalleeFn->hasFnAttribute(Attribute::ReturnsTwice);
}
// Lower a call for the 32-bit ABI.
SDValue
SparcTargetLowering::LowerCall_32(TargetLowering::CallLoweringInfo &CLI,
@ -861,6 +883,7 @@ SparcTargetLowering::LowerCall_32(TargetLowering::CallLoweringInfo &CLI,
}
unsigned SRetArgSize = (hasStructRetAttr)? getSRetArgSize(DAG, Callee):0;
bool hasReturnsTwice = hasReturnsTwiceAttr(DAG, Callee, CLI.CS);
// If the callee is a GlobalAddress node (quite common, every direct call is)
// turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
@ -882,8 +905,11 @@ SparcTargetLowering::LowerCall_32(TargetLowering::CallLoweringInfo &CLI,
RegsToPass[i].second.getValueType()));
// Add a register mask operand representing the call-preserved registers.
const TargetRegisterInfo *TRI = getTargetMachine().getRegisterInfo();
const uint32_t *Mask = TRI->getCallPreservedMask(CallConv);
const SparcRegisterInfo *TRI =
((const SparcTargetMachine&)getTargetMachine()).getRegisterInfo();
const uint32_t *Mask = ((hasReturnsTwice)
? TRI->getRTCallPreservedMask(CallConv)
: TRI->getCallPreservedMask(CallConv));
assert(Mask && "Missing call preserved mask for calling convention");
Ops.push_back(DAG.getRegisterMask(Mask));
@ -1125,6 +1151,7 @@ SparcTargetLowering::LowerCall_64(TargetLowering::CallLoweringInfo &CLI,
// turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
// Likewise ExternalSymbol -> TargetExternalSymbol.
SDValue Callee = CLI.Callee;
bool hasReturnsTwice = hasReturnsTwiceAttr(DAG, Callee, CLI.CS);
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
Callee = DAG.getTargetGlobalAddress(G->getGlobal(), DL, getPointerTy());
else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee))
@ -1139,8 +1166,11 @@ SparcTargetLowering::LowerCall_64(TargetLowering::CallLoweringInfo &CLI,
RegsToPass[i].second.getValueType()));
// Add a register mask operand representing the call-preserved registers.
const TargetRegisterInfo *TRI = getTargetMachine().getRegisterInfo();
const uint32_t *Mask = TRI->getCallPreservedMask(CLI.CallConv);
const SparcRegisterInfo *TRI =
((const SparcTargetMachine&)getTargetMachine()).getRegisterInfo();
const uint32_t *Mask = ((hasReturnsTwice)
? TRI->getRTCallPreservedMask(CLI.CallConv)
: TRI->getCallPreservedMask(CLI.CallConv));
assert(Mask && "Missing call preserved mask for calling convention");
Ops.push_back(DAG.getRegisterMask(Mask));