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[lldb] Add isConstant mode for FA locations #110726

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Merged
merged 3 commits into from
Oct 4, 2024
Merged

[lldb] Add isConstant mode for FA locations #110726

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a23540f
[lldb] Add isConstant mode for FA locations
felipepiovezan Sep 24, 2024
a4b409d
fixup! [lldb] Add isConstant mode for FA locations
felipepiovezan Oct 1, 2024
d1cd2a2
fixup! use process method fix address fixup
felipepiovezan Oct 2, 2024
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12 changes: 12 additions & 0 deletions lldb/include/lldb/Symbol/UnwindPlan.h
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Original file line number Diff line number Diff line change
Expand Up @@ -215,6 +215,7 @@ class UnwindPlan {
isRegisterDereferenced, // FA = [reg]
isDWARFExpression, // FA = eval(dwarf_expr)
isRaSearch, // FA = SP + offset + ???
isConstant, // FA = constant
};

FAValue() : m_value() {}
Expand Down Expand Up @@ -259,6 +260,15 @@ class UnwindPlan {
m_value.expr.length = len;
}

bool IsConstant() const { return m_type == isConstant; }

void SetIsConstant(uint64_t constant) {
m_type = isConstant;
m_value.constant = constant;
}

uint64_t GetConstant() const { return m_value.constant; }

uint32_t GetRegisterNumber() const {
if (m_type == isRegisterDereferenced || m_type == isRegisterPlusOffset)
return m_value.reg.reg_num;
Expand Down Expand Up @@ -329,6 +339,8 @@ class UnwindPlan {
} expr;
// For m_type == isRaSearch
int32_t ra_search_offset;
// For m_type = isConstant
uint64_t constant;
} m_value;
}; // class FAValue

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4 changes: 4 additions & 0 deletions lldb/source/Symbol/UnwindPlan.cpp
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Expand Up @@ -187,6 +187,8 @@ operator==(const UnwindPlan::Row::FAValue &rhs) const {
return !memcmp(m_value.expr.opcodes, rhs.m_value.expr.opcodes,
m_value.expr.length);
break;
case isConstant:
return m_value.constant == rhs.m_value.constant;
}
}
return false;
Expand Down Expand Up @@ -214,6 +216,8 @@ void UnwindPlan::Row::FAValue::Dump(Stream &s, const UnwindPlan *unwind_plan,
case isRaSearch:
s.Printf("RaSearch@SP%+d", m_value.ra_search_offset);
break;
case isConstant:
s.Printf("0x%" PRIx64, m_value.constant);
}
}

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6 changes: 6 additions & 0 deletions lldb/source/Target/RegisterContextUnwind.cpp
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Expand Up @@ -2088,6 +2088,12 @@ bool RegisterContextUnwind::ReadFrameAddress(
UnwindLogMsg("No suitable CFA found");
break;
}
case UnwindPlan::Row::FAValue::isConstant: {
address = fa.GetConstant();
address = abi_sp->FixCodeAddress(address);
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@felipepiovezan felipepiovezan Oct 1, 2024

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@jasonmolenda I see a few other places in this file calling the function above (FixCodeAddress). But there are many other places that just take addresses and use them as is to do things like Process:ReadMemory... it makes me wonder whether we should audit those uses.

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@felipepiovezan felipepiovezan Oct 1, 2024

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For example, line 2051:

if (ABISP abi_sp = m_thread.GetProcess()->GetABI())
        address = abi_sp->FixCodeAddress(address);

Now I wonder if this is shadowing the abi_sp variable...

UnwindLogMsg("CFA value set by constant is 0x%" PRIx64, address);
return true;
}
default:
return false;
}
Expand Down
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