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[BPF] Allow selectively disable compiler builtins for BPF target #4

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Merged
merged 2 commits into from
Feb 17, 2021
Merged

[BPF] Allow selectively disable compiler builtins for BPF target #4

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a868188
[BPF] Add method to check whether a triple is a BPF architecture
dmakarov Feb 17, 2021
6b79107
[BPF] Make rust allocation builtins unavailable for BPF target
dmakarov Feb 17, 2021
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5 changes: 5 additions & 0 deletions llvm/include/llvm/ADT/Triple.h
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Original file line number Diff line number Diff line change
Expand Up @@ -706,6 +706,11 @@ class Triple {
return getArch() == Triple::aarch64 || getArch() == Triple::aarch64_be;
}

/// Tests whether the target is BPF (little and big endian).
bool isBPF() const {
return getArch() == Triple::bpfel || getArch() == Triple::bpfeb;
}

/// Tests whether the target is MIPS 32-bit (little and big endian).
bool isMIPS32() const {
return getArch() == Triple::mips || getArch() == Triple::mipsel;
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10 changes: 8 additions & 2 deletions llvm/lib/Analysis/TargetLibraryInfo.cpp
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Expand Up @@ -550,6 +550,12 @@ static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T,
TLI.setUnavailable(LibFunc_nvvm_reflect);
}

if (T.isBPF()) {
TLI.setUnavailable(LibFunc_rust_alloc);
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Why does llvm have to have any knowledge of these rust functions?

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it does. It replaces them with internal built-ins, which these calls to TLI.setUnavailable() prevent from happening.

TLI.setUnavailable(LibFunc_rust_dealloc);
TLI.setUnavailable(LibFunc_rust_realloc);
}

TLI.addVectorizableFunctionsFromVecLib(ClVectorLibrary);
}

Expand Down Expand Up @@ -1503,9 +1509,9 @@ bool TargetLibraryInfoImpl::getLibFunc(const Function &FDecl,
LibFunc &F) const {
// Intrinsics don't overlap w/libcalls; if our module has a large number of
// intrinsics, this ends up being an interesting compile time win since we
// avoid string normalization and comparison.
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These changes probably not necessary

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let's keep it... the trailing white space is bad in source code (my editor automatically deletes it on saving a file)

// avoid string normalization and comparison.
if (FDecl.isIntrinsic()) return false;

const DataLayout *DL =
FDecl.getParent() ? &FDecl.getParent()->getDataLayout() : nullptr;
return getLibFunc(FDecl.getName(), F) &&
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