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
This commit is contained in:
Evan Cheng 2011-03-24 06:20:03 +00:00
parent e1db1b8d4e
commit d700617193

View File

@ -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<ARMConstantPoolValue*>(MCPE0.Val.MachineCPVal);
ARMConstantPoolValue *ACPV1 =
static_cast<ARMConstantPoolValue*>(MCPE1.Val.MachineCPVal);
return ACPV0->hasSameValue(ACPV1);
bool isARMCP0 = MCPE0.isMachineConstantPoolEntry();
bool isARMCP1 = MCPE1.isMachineConstantPoolEntry();
if (isARMCP0 && isARMCP1) {
ARMConstantPoolValue *ACPV0 =
static_cast<ARMConstantPoolValue*>(MCPE0.Val.MachineCPVal);
ARMConstantPoolValue *ACPV1 =
static_cast<ARMConstantPoolValue*>(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;