[mlir][cmake] Don't add dependencies on mlir-(generic-)headers

[Mogball]

Summary

Every dialect was dependent on mlir-headers, which was causing the
build of any single MLIR dialect to pull in a bunch of extra
dependencies that aren't needed. Now, MLIR dialects will need to
explicitly depend on MLIR*IncGen targets to pull in any needed
headers.

This does not impact the actual mlir-header target.

Consider the "simple" Arithmetic dialect. Before:

% ninja MLIRArithmeticDialect
[151/812] Building CXX object lib/TableGen/CMakeFiles/LLVMTableGen.dir/JSONBackend.cpp.o

After:

% ninja MLIRArithmeticDialect
[207/374] Building CXX object tools/mlir/lib/TableGen/CMakeFiles/MLIRTableGen.dir/GenInfo.cpp.o

(Both clean builds)

[jpienaar]

Nice, and seems like everyone was already doing that in core? (>2x reduction good, always good to occasionally check here)

[rriddle]

Assuming this doesn't blow anything up, LG.

[zero9178]

It seems to be the CI is already failing due to missing dependencies on headers. I also tested the patch and while it did luckily I build I ran ninja -t missingdeps on it afterwards and it flagged a few more missing dependencies on headers https://gist.github.com/zero9178/a1b69d320e9f56f11ec2eb3b30ebf47d. You can run that ninja commandline if you have a new enough version to help you find missing header dependencies. Just make sure its run after the related cpp files have been built so that it picks up the header dependencies. It sadly sometimes has false positives however.

[Mogball]

possibly due to ccache, I'm not able to reproduce these failures locally, so I guess I'm iterating with the bot :(

[mehdi_amini]

This is extremely tricky to get right, I'm quite concern about the blast effect of this.

Please revert for now.

[Mogball]

The bot was green when I landed. Only flang is broken now which I'm fixing. Should I still revert it?

mlir/cmake/modules/AddMLIR.cmake

target_compile_definitions(obj.${name}
     PRIVATE
     -DMLIR_CAPI_BUILDING_LIBRARY=1
   )
 endfunction()
 
 # Declare the library associated with a dialect.
 function(add_mlir_dialect_library name)
   set_property(GLOBAL APPEND PROPERTY MLIR_DIALECT_LIBS ${name})
-  add_mlir_library(${ARGV} DEPENDS mlir-headers)
+  add_mlir_library(${ARGV})
 endfunction(add_mlir_dialect_library)
 
 # Declare the library associated with a conversion.
 function(add_mlir_conversion_library name)
   set_property(GLOBAL APPEND PROPERTY MLIR_CONVERSION_LIBS ${name})
-  add_mlir_library(${ARGV} DEPENDS mlir-headers)
+  add_mlir_library(${ARGV})
 endfunction(add_mlir_conversion_library)
 
 # Declare the library associated with a translation.
 function(add_mlir_translation_library name)
   set_property(GLOBAL APPEND PROPERTY MLIR_TRANSLATION_LIBS ${name})
-  add_mlir_library(${ARGV} DEPENDS mlir-headers)
+  add_mlir_library(${ARGV})
 endfunction(add_mlir_translation_library)
 
 # Verification tools to aid debugging.
 function(mlir_check_link_libraries name)
   if(TARGET ${name})
     get_target_property(type ${name} TYPE)
     if (${type} STREQUAL "INTERFACE_LIBRARY")
       get_target_property(libs ${name} INTERFACE_LINK_LIBRARIES)

mlir/lib/Analysis/CMakeLists.txt

add_mlir_library(MLIRAnalysis
   DataFlow/DeadCodeAnalysis.cpp
   DataFlow/DenseAnalysis.cpp
   DataFlow/IntegerRangeAnalysis.cpp
   DataFlow/SparseAnalysis.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${MLIR_MAIN_INCLUDE_DIR}/mlir/Analysis
 
-  DEPENDS
-  mlir-headers
-
   LINK_LIBS PUBLIC
   MLIRCallInterfaces
   MLIRControlFlowInterfaces
   MLIRDataLayoutInterfaces
   MLIRInferIntRangeInterface
   MLIRInferTypeOpInterface
   MLIRLoopLikeInterface
   MLIRSideEffectInterfaces
   MLIRViewLikeInterface
   )
 
 add_subdirectory(Presburger)

mlir/lib/Dialect/Transform/IR/CMakeLists.txt

 add_mlir_dialect_library(MLIRTransformDialect
   TransformDialect.cpp
   TransformInterfaces.cpp
   TransformOps.cpp
 
   DEPENDS
   MLIRTransformDialectIncGen
   MLIRTransformInterfacesIncGen
+  MLIRTransformOpsIncGen
 
   LINK_LIBS PUBLIC
   MLIRIR
   MLIRPDLDialect
   MLIRPDLInterpDialect
   MLIRRewrite
   MLIRSideEffectInterfaces
   )

mlir/lib/Pass/CMakeLists.txt

 add_mlir_library(MLIRPass
   IRPrinting.cpp
   Pass.cpp
   PassCrashRecovery.cpp
   PassManagerOptions.cpp
   PassRegistry.cpp
   PassStatistics.cpp
   PassTiming.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${MLIR_MAIN_INCLUDE_DIR}/mlir/Pass
 
-  DEPENDS
-  mlir-generic-headers
-
   LINK_LIBS PUBLIC
   MLIRAnalysis
   MLIRIR
   )

mlir/lib/Rewrite/CMakeLists.txt

 add_mlir_library(MLIRRewrite
   ByteCode.cpp
   FrozenRewritePatternSet.cpp
   PatternApplicator.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${MLIR_MAIN_INCLUDE_DIR}/mlir/Rewrite
 
-  DEPENDS
-  mlir-generic-headers
-
   LINK_LIBS PUBLIC
   MLIRIR
   MLIRPDLDialect
   MLIRPDLInterpDialect
   MLIRPDLToPDLInterp
   MLIRSideEffectInterfaces
   )