From d700617193f3d11deb83cd56c4ababbc8e0ea19f Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Thu, 24 Mar 2011 06:20:03 +0000 Subject: [PATCH] Nasty bug in ARMBaseInstrInfo::produceSameValue(). The MachineConstantPoolEntry entries being compared may not be ARMConstantPoolValue. Without checking whether they are ARMConstantPoolValue first, and if the stars and moons are aligned properly, the equality test may return true (when the first few words of two Constants' values happen to be identical) and very bad things can happen. rdar://9125354 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128203 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/ARM/ARMBaseInstrInfo.cpp | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/lib/Target/ARM/ARMBaseInstrInfo.cpp b/lib/Target/ARM/ARMBaseInstrInfo.cpp index b5f20a44021..a2748225a4c 100644 --- a/lib/Target/ARM/ARMBaseInstrInfo.cpp +++ b/lib/Target/ARM/ARMBaseInstrInfo.cpp @@ -1080,11 +1080,18 @@ bool ARMBaseInstrInfo::produceSameValue(const MachineInstr *MI0, int CPI1 = MO1.getIndex(); const MachineConstantPoolEntry &MCPE0 = MCP->getConstants()[CPI0]; const MachineConstantPoolEntry &MCPE1 = MCP->getConstants()[CPI1]; - ARMConstantPoolValue *ACPV0 = - static_cast(MCPE0.Val.MachineCPVal); - ARMConstantPoolValue *ACPV1 = - static_cast(MCPE1.Val.MachineCPVal); - return ACPV0->hasSameValue(ACPV1); + bool isARMCP0 = MCPE0.isMachineConstantPoolEntry(); + bool isARMCP1 = MCPE1.isMachineConstantPoolEntry(); + if (isARMCP0 && isARMCP1) { + ARMConstantPoolValue *ACPV0 = + static_cast(MCPE0.Val.MachineCPVal); + ARMConstantPoolValue *ACPV1 = + static_cast(MCPE1.Val.MachineCPVal); + return ACPV0->hasSameValue(ACPV1); + } else if (!isARMCP0 && !isARMCP1) { + return MCPE0.Val.ConstVal == MCPE1.Val.ConstVal; + } + return false; } else if (Opcode == ARM::PICLDR) { if (MI1->getOpcode() != Opcode) return false;