6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-01-01 00:33:09 +00:00
Code Issues Projects Releases Wiki Activity

Add some checks for MachineCFG consistency. Use AnalyzeBranch and

Browse Source 
do extra checking when it succeeds, as those are cases where
CodeGen will be doing particularly interesting CFG modifications.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80196 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-08-27 02:43:49 +00:00
parent 7008087b8c
commit 27920594b9
1 changed files with 133 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

133
lib/CodeGen/MachineVerifier.cpp
View File

@ -300,6 +300,139 @@ MachineVerifier::visitMachineFunctionBefore()
void
MachineVerifier::visitMachineBasicBlockBefore(const MachineBasicBlock *MBB)
{
const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
// Start with minimal CFG sanity checks.
MachineFunction::const_iterator MBBI = MBB;
++MBBI;
if (MBBI != MF->end()) {
// Block is not last in function.
if (!MBB->isSuccessor(MBBI)) {
// Block does not fall through.
if (MBB->empty()) {
report("MBB doesn't fall through but is empty!", MBB);
}
} else {
// Block falls through.
if (!MBB->empty() && MBB->back().getDesc().isBarrier()) {
report("MBB falls through but ends with a barrier instruction!", MBB);
}
if (TII->BlockHasNoFallThrough(*MBB)) {
report("TargetInstrInfo says the block has no fall through, but the "
"CFG has a fall-through edge!", MBB);
}
}
} else {
// Block is last in function.
if (MBB->empty()) {
report("MBB is last in function but is empty!", MBB);
}
}
// Call AnalyzeBranch. If it succeeds, there several more conditions to check.
MachineBasicBlock *TBB = 0, *FBB = 0;
SmallVector<MachineOperand, 4> Cond;
if (!TII->AnalyzeBranch(*const_cast<MachineBasicBlock *>(MBB),
TBB, FBB, Cond)) {
// Ok, AnalyzeBranch thinks it knows what's going on with this block. Let's
// check whether its answers match up with reality.
if (!TBB && !FBB) {
// Block falls through to its successor.
MachineFunction::const_iterator MBBI = MBB;
++MBBI;
if (MBBI == MF->end()) {
// TODO: This condition is sometimes reached for functions which
// make noreturn calls or contain unreachable. Should AnalyzeBranch
// be changed to handle such cases differently?
report("MBB falls through out of function!", MBB);
} else if (MBB->succ_size() != 1) {
report("MBB exits via unconditional fall-through but doesn't have "
"exactly one CFG successor!", MBB);
} else if (MBB->succ_begin()[0] != MBBI) {
report("MBB exits via unconditional fall-through but its successor "
"differs from its CFG successor!", MBB);
}
if (!MBB->empty() && MBB->back().getDesc().isBarrier()) {
report("MBB exits via unconditional fall-through but ends with a "
"barrier instruction!", MBB);
}
if (!Cond.empty()) {
report("MBB exits via unconditional fall-through but has a condition!",
MBB);
}
} else if (TBB && !FBB && Cond.empty()) {
// Block unconditionally branches somewhere.
if (MBB->succ_size() != 1) {
report("MBB exits via unconditional branch but doesn't have "
"exactly one CFG successor!", MBB);
} else if (MBB->succ_begin()[0] != TBB) {
report("MBB exits via unconditional branch but the CFG "
"successor doesn't match the actual successor!", MBB);
}
if (MBB->empty()) {
report("MBB exits via unconditional branch but doesn't contain "
"any instructions!", MBB);
} else if (!MBB->back().getDesc().isBarrier()) {
report("MBB exits via unconditional branch but doesn't end with a "
"barrier instruction!", MBB);
} else if (!MBB->back().getDesc().isTerminator()) {
report("MBB exits via unconditional branch but the branch isn't a "
"terminator instruction!", MBB);
}
} else if (TBB && !FBB && !Cond.empty()) {
// Block conditionally branches somewhere, otherwise falls through.
MachineFunction::const_iterator MBBI = MBB;
++MBBI;
if (MBBI == MF->end()) {
report("MBB conditionally falls through out of function!", MBB);
} if (MBB->succ_size() != 2) {
report("MBB exits via conditional branch/fall-through but doesn't have "
"exactly two CFG successors!", MBB);
} else if ((MBB->succ_begin()[0] == TBB && MBB->succ_end()[1] == MBBI) ||
(MBB->succ_begin()[1] == TBB && MBB->succ_end()[0] == MBBI)) {
report("MBB exits via conditional branch/fall-through but the CFG "
"successors don't match the actual successors!", MBB);
}
if (MBB->empty()) {
report("MBB exits via conditional branch/fall-through but doesn't "
"contain any instructions!", MBB);
} else if (MBB->back().getDesc().isBarrier()) {
report("MBB exits via conditional branch/fall-through but ends with a "
"barrier instruction!", MBB);
} else if (!MBB->back().getDesc().isTerminator()) {
report("MBB exits via conditional branch/fall-through but the branch "
"isn't a terminator instruction!", MBB);
}
} else if (TBB && FBB) {
// Block conditionally branches somewhere, otherwise branches
// somewhere else.
if (MBB->succ_size() != 2) {
report("MBB exits via conditional branch/branch but doesn't have "
"exactly two CFG successors!", MBB);
} else if ((MBB->succ_begin()[0] == TBB && MBB->succ_end()[1] == FBB) ||
(MBB->succ_begin()[1] == TBB && MBB->succ_end()[0] == FBB)) {
report("MBB exits via conditional branch/branch but the CFG "
"successors don't match the actual successors!", MBB);
}
if (MBB->empty()) {
report("MBB exits via conditional branch/branch but doesn't "
"contain any instructions!", MBB);
} else if (!MBB->back().getDesc().isBarrier()) {
report("MBB exits via conditional branch/branch but doesn't end with a "
"barrier instruction!", MBB);
} else if (!MBB->back().getDesc().isTerminator()) {
report("MBB exits via conditional branch/branch but the branch "
"isn't a terminator instruction!", MBB);
}
if (Cond.empty()) {
report("MBB exits via conditinal branch/branch but there's no "
"condition!", MBB);
}
} else {
report("AnalyzeBranch returned invalid data!", MBB);
}
}
regsLive.clear();
for (MachineBasicBlock::const_livein_iterator I = MBB->livein_begin(),
E = MBB->livein_end(); I != E; ++I) {