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| author | Milian Wolff <mail@milianw.de> | 2016-01-15 13:37:25 (GMT) |
|---|---|---|
| committer | Stephen Kelly <steveire@gmail.com> | 2016-01-20 20:20:55 (GMT) |
| commit | bd2384f593d0cf2c894ff781c4e5278fff2ac96c (patch) | |
| tree | 4febc26007b646519fedf1d72563443fb3fdcedb | |
| parent | ad9394f4fdb69f3f3376d7377fac0a22568aed7c (diff) | |
| download | CMake-bd2384f593d0cf2c894ff781c4e5278fff2ac96c.zip CMake-bd2384f593d0cf2c894ff781c4e5278fff2ac96c.tar.gz CMake-bd2384f593d0cf2c894ff781c4e5278fff2ac96c.tar.bz2 | |
Optimize cmMakefile::ExpandVariablesInStringNew.
We can remove the temporary allocations required for the
default-constructed t_lookup passed into the openstack by refactoring
the code slightly. Furthermore, we use a vector instead of a stack,
since the latter is based on a deque which is not required for a
heap / lifo structure.
This patch removes ~215k allocations.
This hotspot was found with heaptrack.
| -rw-r--r-- | Source/cmMakefile.cxx | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx index 1b0a99a..ba0d672 100644 --- a/Source/cmMakefile.cxx +++ b/Source/cmMakefile.cxx @@ -2832,10 +2832,9 @@ cmake::MessageType cmMakefile::ExpandVariablesInStringNew( const char* last = in; std::string result; result.reserve(source.size()); - std::stack<t_lookup> openstack; + std::vector<t_lookup> openstack; bool error = false; bool done = false; - openstack.push(t_lookup()); cmake::MessageType mtype = cmake::LOG; cmState* state = this->GetCMakeInstance()->GetState(); @@ -2846,10 +2845,10 @@ cmake::MessageType cmMakefile::ExpandVariablesInStringNew( switch(inc) { case '}': - if(openstack.size() > 1) + if(!openstack.empty()) { - t_lookup var = openstack.top(); - openstack.pop(); + t_lookup var = openstack.back(); + openstack.pop_back(); result.append(last, in - last); std::string const& lookup = result.substr(var.loc); const char* value = NULL; @@ -2970,7 +2969,7 @@ cmake::MessageType cmMakefile::ExpandVariablesInStringNew( last = start; in = start - 1; lookup.loc = result.size(); - openstack.push(lookup); + openstack.push_back(lookup); } break; } @@ -2997,7 +2996,7 @@ cmake::MessageType cmMakefile::ExpandVariablesInStringNew( result.append("\r"); last = next + 1; } - else if(nextc == ';' && openstack.size() == 1) + else if(nextc == ';' && openstack.empty()) { // Handled in ExpandListArgument; pass the backslash literally. } @@ -3065,7 +3064,7 @@ cmake::MessageType cmMakefile::ExpandVariablesInStringNew( /* FALLTHROUGH */ default: { - if(openstack.size() > 1 && + if(!openstack.empty() && !(isalnum(inc) || inc == '_' || inc == '/' || inc == '.' || inc == '+' || inc == '-')) @@ -3074,7 +3073,7 @@ cmake::MessageType cmMakefile::ExpandVariablesInStringNew( errorstr += inc; result.append(last, in - last); errorstr += "\') in a variable name: " - "'" + result.substr(openstack.top().loc) + "'"; + "'" + result.substr(openstack.back().loc) + "'"; mtype = cmake::FATAL_ERROR; error = true; } @@ -3085,7 +3084,7 @@ cmake::MessageType cmMakefile::ExpandVariablesInStringNew( } while(!error && !done && *++in); // Check for open variable references yet. - if(!error && openstack.size() != 1) + if(!error && !openstack.empty()) { // There's an open variable reference waiting. Policy CMP0010 flags // whether this is an error or not. The new parser now enforces |