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[llvm-profgen] Fix an out-of-range error during unwinding 

It happened that the LBR entry target can be the first address of text section which causes an out-of-range crash. So here add a boundary check.

Reviewed By: hoy, wenlei

Differential Revision: https://reviews.llvm.org/D110271
This commit is contained in:
wlei 2021-09-22 10:24:54 -07:00
parent c2be2d3284
commit 686cc00067
1 changed files with 19 additions and 6 deletions
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25
llvm/tools/llvm-profgen/PerfReader.cpp
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@ -60,20 +60,33 @@ void VirtualUnwinder::unwindLinear(UnwindState &State, uint64_t Repeat) {
// converted to a list of pseudo probes to report in ProfileGenerator.
State.getParentFrame()->recordRangeCount(Target, End, Repeat);
} else {
// Unwind linear execution part
uint64_t LeafAddr = State.CurrentLeafFrame->Address;
while (IP.Address >= Target) {
// Unwind linear execution part.
// Split and record the range by different inline context. For example:
// [0x01] ... main:1 # Target
// [0x02] ... main:2
// [0x03] ... main:3 @ foo:1
// [0x04] ... main:3 @ foo:2
// [0x05] ... main:3 @ foo:3
// [0x06] ... main:4
// [0x07] ... main:5 # End
// It will be recorded:
// [main:*] : [0x06, 0x07], [0x01, 0x02]
// [main:3 @ foo:*] : [0x03, 0x05]
while (IP.Address > Target) {
uint64_t PrevIP = IP.Address;
IP.backward();
// Break into segments for implicit call/return due to inlining
bool SameInlinee = Binary->inlineContextEqual(PrevIP, IP.Address);
if (!SameInlinee || PrevIP == Target) {
State.switchToFrame(LeafAddr);
if (!SameInlinee) {
State.switchToFrame(PrevIP);
State.CurrentLeafFrame->recordRangeCount(PrevIP, End, Repeat);
End = IP.Address;
}
LeafAddr = IP.Address;
}
assert(IP.Address == Target && "The last one must be the target address.");
// Record the remaining range, [0x01, 0x02] in the example
State.switchToFrame(IP.Address);
State.CurrentLeafFrame->recordRangeCount(IP.Address, End, Repeat);
}
}