Fully fix Bug #22115.

Summary:
In the previous commit, the register was saved, but space was not allocated.
This resulted in the parameter save area potentially clobbering r30, leading to
nasty results.

Test Plan: Tests updated

Reviewers: hfinkel

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6906

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225573 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Justin Hibbits 2015-01-10 01:57:21 +00:00
parent 2ba0f89d9e
commit 1c6936f6d7
4 changed files with 68 additions and 11 deletions

View File

@ -611,6 +611,14 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF) const {
}
}
int PBPOffset = 0;
if (FI->usesPICBase()) {
MachineFrameInfo *FFI = MF.getFrameInfo();
int PBPIndex = FI->getPICBasePointerSaveIndex();
assert(PBPIndex && "No PIC Base Pointer Save Slot!");
PBPOffset = FFI->getObjectOffset(PBPIndex);
}
// Get stack alignments.
unsigned MaxAlign = MFI->getMaxAlignment();
if (HasBP && MaxAlign > 1)
@ -644,12 +652,11 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF) const {
.addImm(FPOffset)
.addReg(SPReg);
if (isPIC && !isDarwinABI && !isPPC64 &&
MF.getInfo<PPCFunctionInfo>()->usesPICBase())
if (FI->usesPICBase())
// FIXME: On PPC32 SVR4, we must not spill before claiming the stackframe.
BuildMI(MBB, MBBI, dl, StoreInst)
.addReg(PPC::R30)
.addImm(-8U)
.addImm(PBPOffset)
.addReg(SPReg);
if (HasBP)
@ -763,6 +770,15 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF) const {
.addCFIIndex(CFIIndex);
}
if (FI->usesPICBase()) {
// Describe where FP was saved, at a fixed offset from CFA.
unsigned Reg = MRI->getDwarfRegNum(PPC::R30, true);
CFIIndex = MMI.addFrameInst(
MCCFIInstruction::createOffset(nullptr, Reg, PBPOffset));
BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
}
if (HasBP) {
// Describe where BP was saved, at a fixed offset from CFA.
unsigned Reg = MRI->getDwarfRegNum(BPReg, true);
@ -932,6 +948,14 @@ void PPCFrameLowering::emitEpilogue(MachineFunction &MF,
}
}
int PBPOffset = 0;
if (FI->usesPICBase()) {
MachineFrameInfo *FFI = MF.getFrameInfo();
int PBPIndex = FI->getPICBasePointerSaveIndex();
assert(PBPIndex && "No PIC Base Pointer Save Slot!");
PBPOffset = FFI->getObjectOffset(PBPIndex);
}
bool UsesTCRet = RetOpcode == PPC::TCRETURNri ||
RetOpcode == PPC::TCRETURNdi ||
RetOpcode == PPC::TCRETURNai ||
@ -1011,12 +1035,11 @@ void PPCFrameLowering::emitEpilogue(MachineFunction &MF,
.addImm(FPOffset)
.addReg(SPReg);
if (isPIC && !isDarwinABI && !isPPC64 &&
MF.getInfo<PPCFunctionInfo>()->usesPICBase())
if (FI->usesPICBase())
// FIXME: On PPC32 SVR4, we must not spill before claiming the stackframe.
BuildMI(MBB, MBBI, dl, LoadInst)
.addReg(PPC::R30)
.addImm(-8U)
.addImm(PBPOffset)
.addReg(SPReg);
if (HasBP)
@ -1135,6 +1158,14 @@ PPCFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
FI->setBasePointerSaveIndex(BPSI);
}
// Reserve stack space for the PIC Base register (R30).
// Only used in SVR4 32-bit.
if (FI->usesPICBase()) {
int PBPSI = FI->getPICBasePointerSaveIndex();
PBPSI = MFI->CreateFixedObject(4, -8, true);
FI->setPICBasePointerSaveIndex(PBPSI);
}
// Reserve stack space to move the linkage area to in case of a tail call.
int TCSPDelta = 0;
if (MF.getTarget().Options.GuaranteedTailCallOpt &&
@ -1266,6 +1297,15 @@ void PPCFrameLowering::processFunctionBeforeFrameFinalized(MachineFunction &MF,
FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI));
}
if (PFI->usesPICBase()) {
HasGPSaveArea = true;
int FI = PFI->getPICBasePointerSaveIndex();
assert(FI && "No PIC Base Pointer Save Slot!");
FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI));
}
const PPCRegisterInfo *RegInfo =
static_cast<const PPCRegisterInfo *>(MF.getSubtarget().getRegisterInfo());
if (RegInfo->hasBasePointer(MF)) {

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@ -35,6 +35,9 @@ class PPCFunctionInfo : public MachineFunctionInfo {
/// Frame index where the old base pointer is stored.
int BasePointerSaveIndex;
/// Frame index where the old PIC base pointer is stored.
int PICBasePointerSaveIndex;
/// MustSaveLR - Indicates whether LR is defined (or clobbered) in the current
/// function. This is only valid after the initial scan of the function by
/// PEI.
@ -103,6 +106,7 @@ public:
: FramePointerSaveIndex(0),
ReturnAddrSaveIndex(0),
BasePointerSaveIndex(0),
PICBasePointerSaveIndex(0),
HasSpills(false),
HasNonRISpills(false),
SpillsCR(false),
@ -128,6 +132,9 @@ public:
int getBasePointerSaveIndex() const { return BasePointerSaveIndex; }
void setBasePointerSaveIndex(int Idx) { BasePointerSaveIndex = Idx; }
int getPICBasePointerSaveIndex() const { return PICBasePointerSaveIndex; }
void setPICBasePointerSaveIndex(int Idx) { PICBasePointerSaveIndex = Idx; }
unsigned getMinReservedArea() const { return MinReservedArea; }
void setMinReservedArea(unsigned size) { MinReservedArea = size; }

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@ -1,9 +1,12 @@
; RUN: llc < %s -mtriple=powerpc-unknown-linux-gnu -relocation-model=pic | FileCheck -check-prefix=LARGE-BSS %s
@bar = common global i32 0, align 4
declare i32 @call_foo(i32, ...)
define i32 @foo() {
entry:
%0 = load i32* @bar, align 4
%call = call i32 (i32, ...)* @call_foo(i32 %0, i32 0, i32 1, i32 2, i32 4, i32 8, i32 16, i32 32, i32 64)
ret i32 %0
}
@ -18,8 +21,9 @@ entry:
; LARGE-BSS: mflr 30
; LARGE-BSS: lwz [[REG:[0-9]+]], [[POFF]]-[[PB]](30)
; LARGE-BSS-NEXT: add 30, [[REG]], 30
; LARGE-BSS: lwz [[VREG:[0-9]+]], [[VREF:\.LC[0-9]+]]-.LTOC(30)
; LARGE-BSS-DAG: lwz [[VREG:[0-9]+]], [[VREF:\.LC[0-9]+]]-.LTOC(30)
; LARGE-BSS-DAG: lwz {{[0-9]+}}, 0([[VREG]])
; LARGE-BSS-DAG: lwz 30, -8(1)
; LARGE-BSS-DAG: stw {{[0-9]+}}, 8(1)
; LARGE-BSS: lwz 30, -8(1)
; LARGE-BSS: [[VREF]]:
; LARGE-BSS-NEXT: .long bar

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@ -1,18 +1,24 @@
; RUN: llc < %s -mtriple=powerpc-unknown-linux-gnu -relocation-model=pic | FileCheck -check-prefix=SMALL-BSS %s
@bar = common global i32 0, align 4
declare i32 @call_foo(i32, ...)
define i32 @foo() {
entry:
%0 = load i32* @bar, align 4
ret i32 %0
%call = call i32 (i32, ...)* @call_foo(i32 %0, i32 0, i32 1, i32 2, i32 4, i32 8, i32 16, i32 32, i32 64)
ret i32 0
}
!llvm.module.flags = !{!0}
!0 = !{i32 1, !"PIC Level", i32 1}
; SMALL-BSS-LABEL:foo:
; SMALL-BSS: stw 30, -8(1)
; SMALL-BSS: stwu 1, -32(1)
; SMALL-BSS: bl _GLOBAL_OFFSET_TABLE_@local-4
; SMALL-BSS: mflr 30
; SMALL-BSS: lwz [[VREG:[0-9]+]], bar@GOT(30)
; SMALL-BSS-DAG: stw {{[0-9]+}}, 8(1)
; SMALL-BSS-DAG: lwz [[VREG:[0-9]+]], bar@GOT(30)
; SMALL-BSS-DAG: lwz {{[0-9]+}}, 0([[VREG]])
; SMALL-BSS-DAG: lwz 30, -8(1)
; SMALL-BSS: bl call_foo@PLT
; SMALL-BSS: lwz 30, -8(1)