p4lang · asl · Nov 25, 2024 · Nov 25, 2024 · Nov 25, 2024 · Nov 26, 2024
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -70,6 +70,7 @@ OPTION (BUILD_AUTO_VAR_INIT_PATTERN "Initialize variables with pattern during bu
 OPTION (ENABLE_IWYU "Enable checking includes with IWYU" OFF)
 # Support a legacy option. TODO: Remove?
 OPTION (ENABLE_UNIFIED_COMPILATION "Enable CMAKE_UNITY_BUILD" OFF)
+OPTION (ENABLE_PCH "Enable PCH for IR headers" OFF)
 
 set (P4C_DRIVER_NAME "p4c" CACHE STRING "Customize the name of the driver script")
 
@@ -135,8 +136,8 @@ if(ENABLE_UNIFIED_COMPILATION)
   set(CMAKE_UNITY_BUILD ON)
 endif()
 
-# If unity builds are enabled, choose an aggressive batch size.
 if (CMAKE_UNITY_BUILD)
+  # If unity builds are enabled, choose an aggressive batch size.
   set(CMAKE_UNITY_BUILD_BATCH_SIZE 10 CACHE UNINITIALIZED "Set the unity build batch size.")
 endif ()
 
@@ -535,7 +536,9 @@ set_source_files_properties(${IR_GENERATOR} PROPERTIES GENERATED TRUE)
 add_library(ir-generated OBJECT ${IR_GENERATED_SRCS} ${EXTENSION_IR_SOURCES})
 add_dependencies(ir-generated ir genIR)
 target_link_libraries(ir-generated PUBLIC ir ${P4C_LIB_DEPS})
-
+if (ENABLE_PCH)
+  target_precompile_headers(ir-generated REUSE_FROM ir)
+endif()
 
 ######################################## IR Generation End ########################################
 

diff --git a/backends/bmv2/CMakeLists.txt b/backends/bmv2/CMakeLists.txt
@@ -105,6 +105,9 @@ target_link_libraries(bmv2backend ir-generated frontend backends-common)
 
 add_executable(p4c-bm2-ss ${BMV2_SIMPLE_SWITCH_SRCS})
 target_link_libraries (p4c-bm2-ss bmv2backend ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
+if (ENABLE_PCH)
+  target_precompile_headers(p4c-bm2-ss REUSE_FROM ir)
+endif()
 
 install(TARGETS p4c-bm2-ss RUNTIME DESTINATION ${P4C_RUNTIME_OUTPUT_DIRECTORY})
 
@@ -113,10 +116,16 @@ target_link_libraries(portable-common bmv2backend)
 
 add_executable(p4c-bm2-psa ${BMV2_PSA_SWITCH_SRCS})
 target_link_libraries (p4c-bm2-psa portable-common ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
+if (ENABLE_PCH)
+  target_precompile_headers(p4c-bm2-psa REUSE_FROM ir)
+endif()
 install(TARGETS p4c-bm2-psa RUNTIME DESTINATION ${P4C_RUNTIME_OUTPUT_DIRECTORY})
 
 add_executable(p4c-bm2-pna ${BMV2_PNA_NIC_SRCS})
 target_link_libraries (p4c-bm2-pna portable-common ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
+if (ENABLE_PCH)
+  target_precompile_headers(p4c-bm2-pna REUSE_FROM ir)
+endif()
 install(TARGETS p4c-bm2-pna RUNTIME DESTINATION ${P4C_RUNTIME_OUTPUT_DIRECTORY})
 
 file(RELATIVE_PATH

diff --git a/backends/dpdk/CMakeLists.txt b/backends/dpdk/CMakeLists.txt
@@ -106,6 +106,9 @@ set(EXTENSION_IR_SOURCES ${EXTENSION_IR_SOURCES} ${QUAL_DPDK_IR_SRCS} PARENT_SCO
 
 add_executable(p4c-dpdk ${P4C_DPDK_SOURCES})
 target_link_libraries (p4c-dpdk dpdk_runtime frontend ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
+if (ENABLE_PCH)
+  target_precompile_headers(p4c-dpdk REUSE_FROM ir)
+endif()
 
 install (TARGETS p4c-dpdk
         RUNTIME DESTINATION ${P4C_RUNTIME_OUTPUT_DIRECTORY})

diff --git a/backends/ebpf/CMakeLists.txt b/backends/ebpf/CMakeLists.txt
@@ -119,7 +119,9 @@ set (P4C_EBPF_DIST_HEADERS
 
 add_executable(p4c-ebpf ${P4C_EBPF_SRCS})
 target_link_libraries (p4c-ebpf ${P4C_LIBRARIES} ${P4C_LIB_DEPS} backends-common)
-add_dependencies(p4c-ebpf ir-generated frontend)
+if (ENABLE_PCH)
+  target_precompile_headers(p4c-ebpf REUSE_FROM ir)
+endif()
 
 install (TARGETS p4c-ebpf
   RUNTIME DESTINATION ${P4C_RUNTIME_OUTPUT_DIRECTORY})

diff --git a/backends/graphs/CMakeLists.txt b/backends/graphs/CMakeLists.txt
@@ -33,7 +33,10 @@ add_library(p4cgraphs STATIC ${GRAPHS_SRCS} ${EXTENSION_P4_14_CONV_SOURCES})
 target_link_libraries(p4cgraphs ir-generated frontend)
 
 add_executable(p4c-graphs p4c-graphs.cpp)
-target_link_libraries (p4c-graphs p4cgraphs ir-generated frontend ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
+target_link_libraries (p4c-graphs p4cgraphs frontend ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
+if (ENABLE_PCH)
+  target_precompile_headers(p4c-graphs REUSE_FROM ir)
+endif()
 
 install (TARGETS p4c-graphs
   RUNTIME DESTINATION ${P4C_RUNTIME_OUTPUT_DIRECTORY})

diff --git a/backends/p4fmt/CMakeLists.txt b/backends/p4fmt/CMakeLists.txt
@@ -17,7 +17,9 @@ set(REFCHECK_SRCS
 # p4fmt
 add_executable(p4fmt ${FMT_SRCS})
 target_link_libraries(p4fmt ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
-add_dependencies(p4fmt frontend)
+if (ENABLE_PCH)
+  target_precompile_headers(p4fmt REUSE_FROM ir)
+endif()
 
 add_custom_target(p4formatter
         COMMAND ${CMAKE_COMMAND} -E create_symlink ${CMAKE_CURRENT_BINARY_DIR}/p4fmt ${P4C_BINARY_DIR}/p4fmt
@@ -26,6 +28,9 @@ add_custom_target(p4formatter
 # p4fmt - reference checker
 add_executable(checkfmt ${REFCHECK_SRCS})
 target_link_libraries(checkfmt ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
+if (ENABLE_PCH)
+  target_precompile_headers(checkfmt REUSE_FROM ir)
+endif()
 
 add_custom_target(p4refchecker
     COMMAND ${CMAKE_COMMAND} -E create_symlink ${CMAKE_CURRENT_BINARY_DIR}/checkfmt ${P4C_BINARY_DIR}/checkfmt

diff --git a/backends/p4test/CMakeLists.txt b/backends/p4test/CMakeLists.txt
@@ -28,7 +28,9 @@ set (P4TEST_HDRS
 
 add_executable(p4test ${P4TEST_SRCS} ${EXTENSION_P4_14_CONV_SOURCES})
 target_link_libraries (p4test ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
-add_dependencies(p4test ir-generated frontend)
+if (ENABLE_PCH)
+  target_precompile_headers(p4test REUSE_FROM ir)
+endif()
 
 install (TARGETS p4test
   RUNTIME DESTINATION ${P4C_RUNTIME_OUTPUT_DIRECTORY})

diff --git a/backends/p4tools/common/CMakeLists.txt b/backends/p4tools/common/CMakeLists.txt
@@ -47,6 +47,9 @@ target_link_libraries(
     # For Abseil includes.
   PRIVATE frontend
 )
+if (ENABLE_PCH)
+  target_precompile_headers(p4tools-common REUSE_FROM ir)
+endif()
 
 target_include_directories(
   p4tools-common

diff --git a/backends/p4tools/modules/smith/CMakeLists.txt b/backends/p4tools/modules/smith/CMakeLists.txt
@@ -63,6 +63,9 @@ target_link_libraries(smith
   # For Abseil includes.
   PRIVATE frontend
 )
+if (ENABLE_PCH)
+  target_precompile_headers(smith REUSE_FROM ir)
+endif()
 
 add_dependencies(smith p4tools-common)
 

diff --git a/backends/p4tools/modules/testgen/CMakeLists.txt b/backends/p4tools/modules/testgen/CMakeLists.txt
@@ -114,6 +114,9 @@ target_link_libraries(testgen
 if (TESTGEN_INCLUDES)
   target_include_directories(testgen ${TESTGEN_INCLUDES})
 endif()
+if (ENABLE_PCH)
+  target_precompile_headers(testgen REUSE_FROM ir)
+endif()
 
 # The executable.
 add_p4tools_executable(p4testgen main.cpp)

diff --git a/backends/tc/CMakeLists.txt b/backends/tc/CMakeLists.txt
@@ -101,7 +101,9 @@ set (IR_DEF_FILES ${IR_DEF_FILES} ${CMAKE_CURRENT_SOURCE_DIR}/tc.def PARENT_SCOP
 # build
 add_executable(p4c-pna-p4tc ${P4TC_BACKEND_SOURCES})
 target_link_libraries (p4c-pna-p4tc ${P4C_LIBRARIES} ${P4C_LIB_DEPS} backends-common)
-add_dependencies(p4c-pna-p4tc genIR)
+if (ENABLE_PCH)
+  target_precompile_headers(p4c-pna-p4tc REUSE_FROM ir)
+endif()
 
 # install
 install (TARGETS p4c-pna-p4tc

diff --git a/backends/ubpf/CMakeLists.txt b/backends/ubpf/CMakeLists.txt
@@ -61,7 +61,9 @@ set (P4C_UBPF_DIST_HEADERS p4include/ubpf_model.p4)
 
 add_executable(p4c-ubpf ${P4C_UBPF_SOURCES})
 target_link_libraries (p4c-ubpf ${P4C_LIBRARIES} ${P4C_LIB_DEPS})
-add_dependencies(p4c-ubpf ir-generated frontend)
+if (ENABLE_PCH)
+  target_precompile_headers(p4c-ubpf REUSE_FROM ir)
+endif()
 
 install (TARGETS p4c-ubpf
         RUNTIME DESTINATION ${P4C_RUNTIME_OUTPUT_DIRECTORY})

diff --git a/frontends/CMakeLists.txt b/frontends/CMakeLists.txt
@@ -281,3 +281,6 @@ target_link_libraries (frontend
   PUBLIC absl::flat_hash_set
   PUBLIC absl::flat_hash_map
 )
+if (ENABLE_PCH)
+  target_precompile_headers(frontend REUSE_FROM ir)
+endif()
diff --git a/ir/CMakeLists.txt b/ir/CMakeLists.txt
@@ -68,11 +68,18 @@ set (BASE_IR_DEF_FILES
 )
 
 set (IR_DEF_FILES ${IR_DEF_FILES} ${BASE_IR_DEF_FILES} PARENT_SCOPE)
+set (PCH_IR_HDRS ${IR_HDRS})
+list(REMOVE_ITEM PCH_IR_HDRS ir-inline.h)
 
-add_library (ir STATIC ${IR_SRCS})
+add_library(ir STATIC ${IR_SRCS})
 target_link_libraries(ir PRIVATE absl::flat_hash_map ${LIBGC_LIBRARIES})
-
-
+if (ENABLE_PCH)
+  # We use PRIVATE here not to populate PRECOMPILED_HEADERS of anything that
+  # links to IR (as this would re-build PCH for every such target). Instead,
+  # we rely on consumer to manage PCH usage explicitly
+  # (e.g. via target_precompile_headers(<user> REUSE_FROM ir)
+  target_precompile_headers(ir PRIVATE ${PCH_IR_HDRS})
+endif()
 add_dependencies(ir genIR)
 
 
diff --git a/ir/irutils.h b/ir/irutils.h
@@ -7,9 +7,11 @@
 #include "lib/big_int_util.h"
 #include "lib/source_file.h"
 
+namespace P4 {
+
 class Transform;
 
-namespace P4::IR {
+namespace IR {
 
 // Forward-declare some IR classes that are used in function declarations.
 class BoolLiteral;
@@ -128,6 +130,8 @@ const IR::Node *inlineBlock(const Transform &, std::initializer_list<const IR::S
 const IR::Node *inlineBlock(const Transform &, const IR::IndexedVector<IR::StatOrDecl> &);
 const IR::Node *inlineBlock(const Transform &, IR::IndexedVector<IR::StatOrDecl> &&);
 
-}  // namespace P4::IR
+}  // namespace IR
+
+}  // namespace P4
 
 #endif /* IR_IRUTILS_H_ */
diff --git a/midend/CMakeLists.txt b/midend/CMakeLists.txt
@@ -123,3 +123,6 @@ target_link_libraries(midend
   PRIVATE frontend
 )
 add_dependencies(midend genIR ir-generated)
+if (ENABLE_PCH)
+  target_precompile_headers(midend REUSE_FROM ir)
+endif()