This reverts commit 5abfde6cb8.
The behaviors associated with implicit pulldown on variable lookup
seriously conflict with the optimizations made in these commits.
Basically, since values were copied upon variable lookup, not just on
PARENT_SCOPE, coupled with PARENT_SCOPE's behavior based on whether the
variable is in the current scope or not causes serious problems with not
storing a value for every variable at every scope.
The commit changed behavior of the following example, among other cases:
function(test_set)
set(blah "value2")
message("before PARENT_SCOPE blah=${blah}")
set(blah ${blah} PARENT_SCOPE)
message("after PARENT_SCOPE blah=${blah}")
endfunction()
set(blah value1)
test_set()
message("in parent scope, blah=${blah}")
Reported-by: Alex Merry <alex.merry@kde.org>
Reported-by: Ben Cooksley <bcooksley@kde.org>
858d5a0b Fix if() checks of CMAKE_SYSTEM_NAME on Cygwin
e177e7af FPHSA: Avoid if() dereferencing of quoted variable
425acc52 cmcurl: Use if(DEFINED) to simplify conditions
cede5cbd libarchive: Avoid depending on if() to dereference a quoted variable
2d97178b FindGTK2: Avoid depending on if() to dereference a quoted variable
0b12815d Modules/Test*.cmake: Use if(DEFINED) to simplify conditions
188a1f23 If: Introduce policy CMP0054 - don't dereference quoted variables in if()
b900c1cc If: Extract cmConditionEvaluator from if() implementation
Reject the option by default. It will be implemented on a per-generator
basis. Pass the setting into try_compile project generation. Add cache
entry CMAKE_GENERATOR_PLATFORM and associated variable documentation to
hold the value persistently.
Add a RunCMake.GeneratorPlatform test to cover basic use cases for the
option. Verify that CMAKE_GENERATOR_PLATFORM is empty by default, and
that it is rejected when the generator does not support a user setting.
No call sites pass NULL to the output argument, so take it by
reference to avoid the if(output) conditions. Propagate the
change through the TryCompile APIs that call it.
When CMP0053 is in WARN mode, variables get expanded twice, leaking the
fact that the string was expanded twice and changing behavior. Instead,
suppress variable watches when running the expansion to trigger the
CMP0053 warning.
The ALLOWED_UNKNOWN_VARIABLE_READ_ACCESS access type was switched on an
undocumented variable and its lookup caused an unnecessary performance
impact. Remove it.
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.
Add properties and variables corresponding to CXX equivalents.
Add features for c_function_prototypes (C90), c_restrict (C99),
c_variadic_macros (C99) and c_static_assert (C11). This feature
set can be extended later.
Add a <PREFIX>_RESTRICT symbol define to WriteCompilerDetectionHeader
to conditionally represent the c_restrict feature.
Introduce a new implementation of ExpandVariablesInString and select
between the old and new implementations based on policy CMP0053.
Instead of cmCommandArgumentParserHelper, use a custom parser with our
own stack. This is much faster and works well for our simple grammar.
The new behavior of CMP0053 should expand @VAR@ syntax only in certain
contexts. All existing EVIS callers use "replaceAt == true" so
hard-code our call to the old implementation. Update the signature to
default to "replaceAt == false" and pass "replaceAt == true" explicitly
in the call sites for configure_file and string(CONFIGURE).
Testing the configure (no generate) step with ParaView shows ~20%
performance improvement.
In terms of complete configure/generate steps, further testing with
ParaView shows a 20% performance improvement over 2.8.12.2 with Unix
Makefiles and minimal with Ninja. Ninja is less because it generate step
is the expensive part (future work will address this) by a long shot and
these changes help the configure step for the most part.
3f517522 StoreMatches: Minor cleanups
ef62fbad ClearMatches: Store match variable names statically
f718b30a ClearMatches: Only clear matches which were actually set
ClearMatches was clearing many variables which were never set in the
first place. Instead, store how many matches were made last time and
only clear those. It is moved to the cmMakefile class since it is a
common utility used by multiple commands.
Users of the new target_compile_features command are expected to
check the existence of the CMAKE_CXX_COMPILE_FEATURES variable before
attempting to use it to require features.
Brad King
Ben Boeckel
Nils Gladitz
Stephen Kelly