The change in commit v3.5.0-rc1~198^2 (Ninja: Always re-run custom
commands that have symbolic dependencies, 2015-11-19) broke the
byproducts feature added by commit v3.2.0-rc1~340^2~2 (Add an option for
explicit BYPRODUCTS of custom commands, 2014-11-13) when SYMBOLIC
outputs also appear. This case occurs with AUTORCC-generated custom
targets because the output is SYMBOLIC (to always run) and the generated
file is a byproduct (for restat so dependents do not run unnecessarily).
The two use cases conflict because Ninja does not support per-output
restat. Favor restat whenever byproducts are present because it is
required for byproducts to work correctly. In use cases where we want
an always-run chain we simply will not be able to also use byproducts.
Fix logic introduced by commit v3.5.0-rc1~198^2 (Ninja: Always re-run
custom commands that have symbolic dependencies, 2015-11-19) to not
consider only the last output. We need to know if any output is
SYMBOLIC, so stop checking as soon as one is found.
Generate custom command build statements in the order we encounter
source files specifying them. Do not depend on pointer values of
internally allocated structures for ordering.
If a custom command has a SYMBOLIC output (that is never actually
created) then do not mark the custom command build statement as
'restat'. Otherwise other custom commands that depend on the symbolic
output may not always re-run because after running the first custom
command Ninja 'restat' will detect that the output timestamp did not
change and skip its dependents.
This was observed with the ExternalProject BUILD_ALWAYS option where
Ninja would not re-run the 'install' step each time 'build' re-runs.
55474e61 cmState: Move GetTargetTypeName from cmTarget.
38df5c36 Remove now-obsolete casts.
4ee2b267 cmGeneratorTarget: Use enum for GetType.
eac15298 cmState: Move TargetType enum from cmTarget.
482b3811 cmTarget: Move link type enum out.
2ee1cb85 cmTarget: Move ImportInfoMap out of internal class.
a48bcabd cmTarget: Move backtrace member out of internal class.
6694d993 cmTarget: Remove unneeded constructors.
983c00f8 Generators: Use GetType from the cmGeneratorTarget.
In the Ninja generator we run all build rules from the top of the build
tree rather than changing into each subdirectory. Therefore we convert
all paths relative to the HOME_OUTPUT directory. However, the Convert
method on cmLocalGenerator restricts relative path conversions to avoid
leaving the build tree with a "../" sequence. Therefore conversions
performed for "subdirectories" that are outside the top of the build
tree always use full paths while conversions performed for
subdirectories that are inside the top of the build tree may use
relative paths to refer to the same files.
Since Ninja always runs rules from the top of the build tree we should
convert them using only the top-level cmLocalGenerator in order to
remain consistent. Also extend the test suite with a case that fails
without this fix.
Refactor the local generator creation API to accept a
cmState::Snapshot. Adjust MakeLocalGenerator to use the 'current'
snapshot in cases where there is no parent. Create the snapshot
for subdirectories in cmMakefile::AddSubdirectory.
This means that snapshots are now created at the point of extending the tree,
as appropriate, and independently of the cmLocalGenerator and cmMakefile they
represent the state for.
Global properties are already global in scope, so remove the
overload for specifying it and port users of the API.
The call from cmMakefile::GetProperty can be simplified because
the scope is only used during chaining, and there is no further
chaining after processing global properties.
A common idiom in CMake-based build systems is to have custom commands
that generate files not listed explicitly as outputs so that these
files do not have to be newer than the inputs. The file modification
times of such "byproducts" are updated only when their content changes.
Then other build rules can depend on the byproducts explicitly so that
their dependents rebuild when the content of the original byproducts
really does change.
This "undeclared byproduct" approach is necessary for Makefile, VS, and
Xcode build tools because if a byproduct were listed as an output of a
rule then the rule would always rerun when the input is newer than the
byproduct but the byproduct may never be updated.
Ninja solves this problem by offering a 'restat' feature to check
whether an output was really modified after running a rule and tracking
the fact that it is up to date separately from its timestamp. However,
Ninja also stats all dependencies up front and will only restat files
that are listed as outputs of rules with the 'restat' option enabled.
Therefore an undeclared byproduct that does not exist at the start of
the build will be considered missing and the build will fail even if
other dependencies would cause the byproduct to be available before its
dependents build.
CMake works around this limitation by adding 'phony' build rules for
custom command dependencies in the build tree that do not have any
explicit specification of what produces them. This is not optimal
because it prevents Ninja from reporting an error when an input to a
rule really is missing. A better approach is to allow projects to
explicitly specify the byproducts of their custom commands so that no
phony rules are needed for them. In order to work with the non-Ninja
generators, the byproducts must be known separately from the outputs.
Add a new "BYPRODUCTS" option to the add_custom_command and
add_custom_target commands to specify byproducts explicitly. Teach the
Ninja generator to specify byproducts as outputs of the custom commands.
In the case of POST_BUILD, PRE_LINK, and PRE_BUILD events on targets
that link, the byproducts must be specified as outputs of the link rule
that runs the commands. Activate 'restat' for such rules so that Ninja
knows it needs to check the byproducts, but not for link rules that have
no byproducts.
Changes in commit b9aa5041 (cmLocalGenerator: Simplify GetIncludeFlags
output formatting, 2014-03-04) caused Windows Resource Compiler include
directories to be computed as relative paths in the Ninja generator.
This breaks the cmcldeps handling of include paths. The reason for the
regression is that several cmLocalGenerator::GetIncludeFlags callers
treated the fourth "bool forResponseFile" argument as if it controlled
whether include directories were a full path. It actually did control
that by accident until the above commit.
Add an explicit "bool forceFullPaths" argument to GetIncludeFlags
and thread the value through ConvertToIncludeReference as needed.
Update GetIncludeFlags call sites that really wanted to control the
forResponseFile setting to be aware of the new argument. Extend the
VSResource test to cover this case.
The pre-defined 'console' pool is a non-buffered pool that runs with a
depth of 1. CMake re-run cannot be run concurrently and it will
eventually output something. A non-buffered pool allows to get it as
soon as possible
Also, generate the minimal required version of Ninja in the build file.
Until now the cmCustomCommandGenerator was used only to compute the
command lines of a custom command. Generalize it to get the comment,
working directory, dependencies, and outputs of custom commands. Update
use in all generators to support this.
Brad King
Stephen Kelly
James Johnston
Peter Collingbourne
Nils Gladitz
Sylvain Joubert
Ben Boeckel