1212# See the License for the specific language governing permissions and
1313# limitations under the License.
1414
15- """Functionality releated to detecting whole-module optimization."""
15+ """Detection of various optimization settings ."""
1616
1717load (
1818 ":feature_names.bzl" ,
19+ "SWIFT_FEATURE_COMPILE_IN_PARALLEL" ,
1920 "SWIFT_FEATURE__NUM_THREADS_0_IN_SWIFTCOPTS" ,
2021 "SWIFT_FEATURE__WMO_IN_SWIFTCOPTS" ,
2122)
@@ -28,29 +29,14 @@ _WMO_FLAGS = {
2829 "-force-single-frontend-invocation" : True ,
2930}
3031
31- def features_from_swiftcopts (swiftcopts ):
32- """Returns a list of features to enable based on `--swiftcopt` flags.
33-
34- Since `--swiftcopt` flags are hooked into the action configuration when the
35- toolchain is configured, it's not possible for individual actions to query
36- them easily if those flags may determine the nature of outputs (for example,
37- single- vs. multi-threaded WMO). The toolchain can call this function to map
38- those flags to private features that can be queried instead.
39-
40- Args:
41- swiftcopts: The list of command line flags that were passed using
42- `--swiftcopt`.
43-
44- Returns:
45- A list (possibly empty) of strings denoting feature names that should be
46- enabled on the toolchain.
47- """
48- features = []
49- if is_wmo_manually_requested (user_compile_flags = swiftcopts ):
50- features .append (SWIFT_FEATURE__WMO_IN_SWIFTCOPTS )
51- if find_num_threads_flag_value (user_compile_flags = swiftcopts ) == 0 :
52- features .append (SWIFT_FEATURE__NUM_THREADS_0_IN_SWIFTCOPTS )
53- return features
32+ # Swift command line flags in the `O` group that enable some kind of
33+ # optimization. This explicitly excludes `-Onone`.
34+ _OPT_FLAGS = {
35+ "-O" : True ,
36+ "-Oplayground" : True ,
37+ "-Osize" : True ,
38+ "-Ounchecked" : True ,
39+ }
5440
5541def find_num_threads_flag_value (user_compile_flags ):
5642 """Finds the value of the `-num-threads` flag.
@@ -75,6 +61,20 @@ def find_num_threads_flag_value(user_compile_flags):
7561 saw_num_threads = True
7662 return num_threads
7763
64+ def is_optimization_manually_requested (user_compile_flags ):
65+ """Returns `True` if some optimization flag is in the given list of flags.
66+
67+ Args:
68+ user_compile_flags: A list of compiler flags to scan for optimization.
69+
70+ Returns:
71+ True if some optimization is enabled in the given list of flags.
72+ """
73+ for copt in user_compile_flags :
74+ if copt in _OPT_FLAGS :
75+ return True
76+ return False
77+
7878def is_wmo_manually_requested (user_compile_flags ):
7979 """Returns `True` if a WMO flag is in the given list of compiler flags.
8080
@@ -89,8 +89,8 @@ def is_wmo_manually_requested(user_compile_flags):
8989 return True
9090 return False
9191
92- def wmo_features_from_swiftcopts (swiftcopts ):
93- """Returns a list of features to enable based on `--swiftcopt` flags.
92+ def optimization_features_from_swiftcopts (swiftcopts ):
93+ """Returns features to enable or disable based on `--swiftcopt` flags.
9494
9595 Since `--swiftcopt` flags are hooked into the action configuration when the
9696 toolchain is configured, it's not possible for individual actions to query
@@ -103,15 +103,29 @@ def wmo_features_from_swiftcopts(swiftcopts):
103103 `--swiftcopt`.
104104
105105 Returns:
106- A list (possibly empty) of strings denoting feature names that should be
107- enabled on the toolchain.
106+ A tuple containing two lists:
107+
108+ 1. A list (possibly empty) of strings denoting feature names that
109+ should be enabled on the toolchain.
110+ 2. A list (possibly empty) of strings denoting feature names that
111+ should be disabled on the toolchain.
108112 """
109- features = []
113+ requested_features = []
114+ unsupported_features = []
115+
116+ if is_optimization_manually_requested (user_compile_flags = swiftcopts ):
117+ # Disable parallel compilation early if we know we're going to be doing
118+ # an optimized compile, because the driver will not emit separate jobs
119+ # unless we also explicitly disable cross-module optimization. See
120+ # https://github.com/swiftlang/swift-driver/blob/c647e91574122f2b104d294ab1ec5baadaa1aa95/Sources/SwiftDriver/Jobs/EmitModuleJob.swift#L156-L181.
121+ unsupported_features .append (SWIFT_FEATURE_COMPILE_IN_PARALLEL )
122+
110123 if is_wmo_manually_requested (user_compile_flags = swiftcopts ):
111- features .append (SWIFT_FEATURE__WMO_IN_SWIFTCOPTS )
124+ requested_features .append (SWIFT_FEATURE__WMO_IN_SWIFTCOPTS )
112125 if find_num_threads_flag_value (user_compile_flags = swiftcopts ) == 1 :
113- features .append (SWIFT_FEATURE__NUM_THREADS_0_IN_SWIFTCOPTS )
114- return features
126+ requested_features .append (SWIFT_FEATURE__NUM_THREADS_0_IN_SWIFTCOPTS )
127+
128+ return requested_features , unsupported_features
115129
116130def _safe_int (s ):
117131 """Returns the base-10 integer value of `s` or `None` if it is invalid.
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