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cmPolicies: Store all statuses in a single bitset. 

Currently there are an optimal number of policies (64) such that
there are no wasted bits.  When another policy is added, the
cmPolicyMap will grow from 40 bytes to 80, and occupy 45.  By storing
all in a single bitset, we stay under the cache line size of 64 bytes
until there are 512 policies in a range.
This commit is contained in:
Stephen Kelly 2015-06-06 09:41:05 +02:00
parent 44a8115797
commit 93cc2eef38
2 changed files with 19 additions and 18 deletions
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30
Source/cmPolicies.cxx
View File

@ -348,19 +348,19 @@ cmPolicies::PolicyMap::Get(cmPolicies::PolicyID id) const
{ {
PolicyStatus status = cmPolicies::WARN; PolicyStatus status = cmPolicies::WARN;
if (this->OLD[id]) if (this->Status[(POLICY_STATUS_COUNT * id) + OLD])
{ {
status = cmPolicies::OLD; status = cmPolicies::OLD;
} }
else if (this->NEW[id]) else if (this->Status[(POLICY_STATUS_COUNT * id) + NEW])
{ {
status = cmPolicies::NEW; status = cmPolicies::NEW;
} }
else if (this->REQUIRED_ALWAYS[id]) else if (this->Status[(POLICY_STATUS_COUNT * id) + REQUIRED_ALWAYS])
{ {
status = cmPolicies::REQUIRED_ALWAYS; status = cmPolicies::REQUIRED_ALWAYS;
} }
else if (this->REQUIRED_IF_USED[id]) else if (this->Status[(POLICY_STATUS_COUNT * id) + REQUIRED_IF_USED])
{ {
status = cmPolicies::REQUIRED_IF_USED; status = cmPolicies::REQUIRED_IF_USED;
} }
@ -370,21 +370,25 @@ cmPolicies::PolicyMap::Get(cmPolicies::PolicyID id) const
void cmPolicies::PolicyMap::Set(cmPolicies::PolicyID id, void cmPolicies::PolicyMap::Set(cmPolicies::PolicyID id,
cmPolicies::PolicyStatus status) cmPolicies::PolicyStatus status)
{ {
this->OLD[id] = (status == cmPolicies::OLD); this->Status[(POLICY_STATUS_COUNT * id) + OLD] = (status == OLD);
this->WARN[id] = (status == cmPolicies::WARN); this->Status[(POLICY_STATUS_COUNT * id) + WARN] = (status == WARN);
this->NEW[id] = (status == cmPolicies::NEW); this->Status[(POLICY_STATUS_COUNT * id) + NEW] = (status == NEW);
this->REQUIRED_ALWAYS[id] = (status == cmPolicies::REQUIRED_ALWAYS); this->Status[(POLICY_STATUS_COUNT * id) + REQUIRED_ALWAYS] =
this->REQUIRED_IF_USED[id] = (status == cmPolicies::REQUIRED_IF_USED); (status == REQUIRED_ALWAYS);
this->Status[(POLICY_STATUS_COUNT * id) + REQUIRED_IF_USED] =
(status == REQUIRED_IF_USED);
} }
bool cmPolicies::PolicyMap::IsDefined(cmPolicies::PolicyID id) const bool cmPolicies::PolicyMap::IsDefined(cmPolicies::PolicyID id) const
{ {
return this->OLD[id] || this->WARN[id] || this->NEW[id] return this->Status[(POLICY_STATUS_COUNT * id) + OLD]
|| this->REQUIRED_ALWAYS[id] || this->REQUIRED_IF_USED[id]; || this->Status[(POLICY_STATUS_COUNT * id) + WARN]
|| this->Status[(POLICY_STATUS_COUNT * id) + NEW]
|| this->Status[(POLICY_STATUS_COUNT * id) + REQUIRED_ALWAYS]
|| this->Status[(POLICY_STATUS_COUNT * id) + REQUIRED_IF_USED];
} }
bool cmPolicies::PolicyMap::IsEmpty() const bool cmPolicies::PolicyMap::IsEmpty() const
{ {
return this->OLD.none() && this->WARN.none() && this->NEW.none() return this->Status.none();
&& this->REQUIRED_ALWAYS.none() && this->REQUIRED_IF_USED.none();
} }

7
Source/cmPolicies.h
View File

@ -244,6 +244,7 @@ public:
REQUIRED_IF_USED, REQUIRED_IF_USED,
REQUIRED_ALWAYS ///< Issue an error unless user sets policy status to NEW. REQUIRED_ALWAYS ///< Issue an error unless user sets policy status to NEW.
}; };
#define POLICY_STATUS_COUNT 5
/// Policy identifiers /// Policy identifiers
enum PolicyID enum PolicyID
@ -287,11 +288,7 @@ public:
bool IsEmpty() const; bool IsEmpty() const;
private: private:
std::bitset<cmPolicies::CMPCOUNT> OLD; std::bitset<cmPolicies::CMPCOUNT * POLICY_STATUS_COUNT> Status;
std::bitset<cmPolicies::CMPCOUNT> WARN;
std::bitset<cmPolicies::CMPCOUNT> NEW;
std::bitset<cmPolicies::CMPCOUNT> REQUIRED_IF_USED;
std::bitset<cmPolicies::CMPCOUNT> REQUIRED_ALWAYS;
}; };
}; };