================
@@ -53,6 +54,37 @@ bool DWARFExpressionList::ContainsAddress(lldb::addr_t
func_load_addr,
return GetExpressionAtAddress(func_load_addr, addr) != nullptr;
}
+std::optional<DWARFExpressionList::DWARFExpressionEntry>
+DWARFExpressionList::GetExpressionEntryAtAddress(lldb::addr_t func_load_addr,
+ lldb::addr_t load_addr) const {
+ if (const DWARFExpression *always = GetAlwaysValidExpr()) {
+ return DWARFExpressionEntry{std::nullopt, always};
+ }
+
+ if (func_load_addr == LLDB_INVALID_ADDRESS)
+ func_load_addr = m_func_file_addr;
+
+ // Guard against underflow when translating a load address back into file
space.
+ if (load_addr < func_load_addr)
+ return std::nullopt;
+
+ // Guard against overflow.
+ lldb::addr_t delta = load_addr - func_load_addr;
+ if (delta > std::numeric_limits<lldb::addr_t>::max() - m_func_file_addr)
----------------
UltimateForce21 wrote:
>From when I dug into MathExtras last time, I found that its `AddOverflow` and
>`SubOverflow` helpers are only defined for **signed types**.
I they rely on two’s-complement signed overflow semantics and return the
truncated signed result. Since `lldb::addr_t` is an **unsigned address,** I
think using those helpers would either fail to compile or silently convert to
signed semantics.
That's why I tried to implement the signed overflow check into the function.
https://github.com/llvm/llvm-project/pull/147460
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