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core: address error=array-bounds in gcc14 #2639

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Jan 10, 2025
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core: address error=array-bounds in gcc14 #2639

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core: address error=array-bounds in gcc14
yperbasis Jan 8, 2025
94ea83e
Return nullopt instead of assertion failure
yperbasis Jan 9, 2025
0258ca0
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yperbasis Jan 9, 2025
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2 changes: 1 addition & 1 deletion silkworm/core/common/assert.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@
#pragma once

namespace silkworm {
void abort_due_to_assertion_failure(char const* expr, char const* file, int line);
[[noreturn]] void abort_due_to_assertion_failure(char const* expr, char const* file, int line);
}

// SILKWORM_ASSERT always aborts program execution on assertion failure, even when NDEBUG is defined.
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16 changes: 10 additions & 6 deletions silkworm/core/common/small_map.hpp
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Expand Up @@ -29,15 +29,15 @@
namespace silkworm {

// SmallMap is a constexpr-friendly immutable map suitable for a small number of elements.
template <std::totally_ordered Key, std::default_initializable T, size_t max_size = 8>
template <std::totally_ordered Key, std::default_initializable T, size_t maximum_size = 8>
class SmallMap {
public:
using ValueType = std::pair<Key, T>;

constexpr SmallMap() noexcept = default;

constexpr SmallMap(std::initializer_list<ValueType> init) : size_(init.size()) {
SILKWORM_ASSERT(size_ <= max_size);
SILKWORM_ASSERT(size_ <= maximum_size);
for (size_t i{0}; i < size_; ++i) {
data_[i] = *(std::data(init) + i);
}
Expand All @@ -47,14 +47,14 @@ class SmallMap {
template <std::input_iterator InputIt>
constexpr SmallMap(InputIt first, InputIt last) {
for (InputIt it{first}; it != last; ++it) {
SILKWORM_ASSERT(size_ < max_size);
SILKWORM_ASSERT(size_ < maximum_size);
data_[size_++] = *it;
}
sort();
}

constexpr SmallMap(const SmallMap& other) : size_{other.size_} {
for (size_t i{0}; i < max_size; ++i) {
for (size_t i{0}; i < maximum_size; ++i) {
data_[i] = other.data_[i];
}
}
Expand All @@ -63,7 +63,7 @@ class SmallMap {
return *this;
}
size_ = other.size_;
for (size_t i{0}; i < max_size; ++i) {
for (size_t i{0}; i < maximum_size; ++i) {
data_[i] = other.data_[i];
}
return *this;
Expand All @@ -77,6 +77,10 @@ class SmallMap {
return size_;
}

static constexpr size_t max_size() noexcept {
return maximum_size;
}

constexpr auto begin() const noexcept {
return data_.begin();
}
Expand Down Expand Up @@ -110,7 +114,7 @@ class SmallMap {
[](const ValueType& a, const ValueType& b) { return a.first < b.first; });
}

std::array<ValueType, max_size> data_{};
std::array<ValueType, maximum_size> data_{};
size_t size_{0};
};

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10 changes: 10 additions & 0 deletions silkworm/core/protocol/bor/config.cpp
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Expand Up @@ -65,13 +65,23 @@ std::optional<Config> Config::from_json(const nlohmann::json& json) noexcept {
const BlockNum from{std::stoull(item.key(), nullptr, 0)};
period.emplace_back(from, item.value().get<uint64_t>());
}
if (period.size() > config.period.max_size()) {
return std::nullopt;
}
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Warray-bounds"
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is this still needed given the if-check above?

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is this still needed given the if-check above?

The error is still emitted unfortunately even with the check.

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@battlmonstr battlmonstr Jan 9, 2025 •
edited
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could you clarify the error? how does a big number like "576460752303423485" or "9223372036854775760" end up there despite the check? who is passing that number? could it be that if is faulty due to some signed-unsigned UB?

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I don't know where this number comes from (it's some internal details of the array-bounds check in gcc). The comparison is fine (both arguments are of type size_t).

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This warning comes from optimized GCC builds. After some optimizations related to inlining and constant propagation compiler can convince itself that it knows the access index of an array and compare it with the array size.
Unfortunately, this analysis is known to have false-positives, see e.g.

If we want to be nice and you think it is worth the time I can reduce this example and report an issue. Or I can make a tutorial how to reduce failing compilations.

// silence misdiagnostics in gcc 14
config.period = {period.begin(), period.end()};
#pragma GCC diagnostic pop

std::vector<std::pair<BlockNum, uint64_t>> sprint;
for (const auto& item : json["sprint"].items()) {
const BlockNum from{std::stoull(item.key(), nullptr, 0)};
sprint.emplace_back(from, item.value().get<uint64_t>());
}
if (sprint.size() > config.sprint.max_size()) {
return std::nullopt;
}
config.sprint = {sprint.begin(), sprint.end()};

config.validator_contract = hex_to_address(json["validatorContract"].get<std::string>(), /*return_zero_on_err=*/true);
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