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[BOLT] Restrict ICP for functions with unknown control flow 

ICP has two modes: jump table promotion and indirect call promotion.
The selection is based on whether an instruction has a jump table or not.
An instruction with unknown control flow doesn't have a jump table and will
fall under indirect call promotion policy which might be incorrect/unsafe
(if an instruction is not a tail call, i.e. has local jump targets).

Prevent ICP for functions containing instructions with unknown control flow.

Follow-up to https://reviews.llvm.org/D128870.

Reviewed By: maksfb

Differential Revision: https://reviews.llvm.org/D132882
This commit is contained in:
Amir Ayupov 2022-09-08 15:50:25 -07:00
parent 873942e178
commit 31abde43d6
2 changed files with 6 additions and 3 deletions
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4
bolt/include/bolt/Passes/IndirectCallPromotion.h
View File

@ -217,6 +217,10 @@ public:
bool shouldPrint(const BinaryFunction &BF) const override {
return BinaryFunctionPass::shouldPrint(BF) && Modified.count(&BF) > 0;
}
bool shouldOptimize(const BinaryFunction &BF) const override {
return BF.isSimple() && !BF.isIgnored() && BF.hasProfile() &&
!BF.hasUnknownControlFlow();
}
void runOnFunctions(BinaryContext &BC) override;
};

5
bolt/lib/Passes/IndirectCallPromotion.cpp
View File

@ -1158,8 +1158,7 @@ void IndirectCallPromotion::runOnFunctions(BinaryContext &BC) {
for (auto &BFIt : BFs) {
BinaryFunction &Function = BFIt.second;
if (!Function.isSimple() || Function.isIgnored() ||
!Function.hasProfile())
if (!shouldOptimize(Function))
continue;
const bool HasLayout = !Function.getLayout().block_empty();
@ -1219,7 +1218,7 @@ void IndirectCallPromotion::runOnFunctions(BinaryContext &BC) {
for (BinaryFunction *FuncPtr : Functions) {
BinaryFunction &Function = *FuncPtr;
if (!Function.isSimple() || Function.isIgnored() || !Function.hasProfile())
if (!shouldOptimize(Function))
continue;
const bool HasLayout = !Function.getLayout().block_empty();