Allow setting build properties based on the features available
for a target. The availability of features is determined at
generate-time by evaluating the link implementation.
Ensure that the <LANG>_STANDARD determined while evaluating
COMPILE_FEATURES in the link implementation is not lower than that
provided by the INTERFACE of the link implementation. This is
similar to handling of transitive properties such as
POSITION_INDEPENDENT_CODE.
The output of this expression may contain macros for IDEs to replace
such as $(Configuration), $(CURRENT_ARCH) etc. To avoid generating
content which is not usable in other contexts, report an error if
there is an attempt to use it in other contexts.
This commit may be reverted in the future if a solution to the
above difference is implemented.
Casts from std::string -> cmStdString were high on the list of things
taking up time. Avoid such implicit casts across function calls by just
using std::string everywhere.
The comment that the symbol name is too long is no longer relevant since
modern debuggers alias the templates anyways and the size is a
non-issue since the underlying methods are generated since it's
inherited.
This has follow-on effects for other methods and classes. Further
work on making the use of const cmTarget pointers common can be
done, particularly with a view to generate-time methods.
CMake/Source/cmGeneratorExpressionParser.cxx: In member function ‘void cmGeneratorExpressionParser::ParseGeneratorExpression(std::vector<cmGeneratorExpressionEvaluator*>&)’:
CMake/Source/cmGeneratorExpressionParser.cxx:116:55: warning: conversion to ‘unsigned int’ from ‘long int’ may alter its value [-Wconversion]
CMake/Source/cmGeneratorExpressionParser.cxx:240:39: warning: conversion to ‘int’ from ‘long int’ may alter its value [-Wconversion]
Generator expressions whose output depends on the configuration
now record that fact. The GetIncludeDirectories method can use
that result to cache the include directories for later calls.
GetIncludeDirectories is called multiple times for a target
for each configuration, so this should restore performance for
multi-config generators.
Following from the discussion here:
http://thread.gmane.org/gmane.comp.programming.tools.cmake.devel/3615/focus=5170
(Re: Generator expressisons in target properties, 26 Oct 12:10)
we can't split cmTarget API for linking into cmGeneratorTarget. In
the future we will probably also need to move the include and compile
definitions API back to cmTarget so that it can be used by export().
There are two overloads, so that it can use the operational
target when a target property is being evaluated, and a target
can alternatively be specified by name.
At this point, the generators don't chain. That comes later.
The expressions may be parsed and then cached and evaluated multiple
times. They are evaluated lazily so that literals such as ',' can be
treated as universal parameter separators, and can be processed from
results without appearing literally, and without interfering with the
parsing/evaluation of the entire expression.