[llvm] r373664 - Reland r349624: Let TableGen write output only if it changed, instead of doing so in cmake
Nico Weber via llvm-commits
llvm-commits at lists.llvm.org
Thu Oct 3 14:22:29 PDT 2019
Author: nico
Date: Thu Oct 3 14:22:28 2019
New Revision: 373664
URL: http://llvm.org/viewvc/llvm-project?rev=373664&view=rev
Log:
Reland r349624: Let TableGen write output only if it changed, instead of doing so in cmake
Move the write-if-changed logic behind a flag and don't pass it
with the MSVC generator. msbuild doesn't have a restat optimization,
so not doing write-if-change there doesn't have a cost, and it
should fix whatever causes PR43385.
Modified:
llvm/trunk/cmake/modules/TableGen.cmake
llvm/trunk/lib/TableGen/Main.cpp
llvm/trunk/utils/gn/secondary/llvm/utils/TableGen/tablegen.gni
Modified: llvm/trunk/cmake/modules/TableGen.cmake
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/cmake/modules/TableGen.cmake?rev=373664&r1=373663&r2=373664&view=diff
==============================================================================
--- llvm/trunk/cmake/modules/TableGen.cmake (original)
+++ llvm/trunk/cmake/modules/TableGen.cmake Thu Oct 3 14:22:28 2019
@@ -23,7 +23,7 @@ function(tablegen project ofn)
file(RELATIVE_PATH ofn_rel
${CMAKE_BINARY_DIR} ${CMAKE_CURRENT_BINARY_DIR}/${ofn})
set(additional_cmdline
- -o ${ofn_rel}.tmp
+ -o ${ofn_rel}
-d ${ofn_rel}.d
WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
DEPFILE ${CMAKE_CURRENT_BINARY_DIR}/${ofn}.d
@@ -34,7 +34,7 @@ function(tablegen project ofn)
file(GLOB local_tds "*.td")
file(GLOB_RECURSE global_tds "${LLVM_MAIN_INCLUDE_DIR}/llvm/*.td")
set(additional_cmdline
- -o ${CMAKE_CURRENT_BINARY_DIR}/${ofn}.tmp
+ -o ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
)
endif()
@@ -58,6 +58,15 @@ function(tablegen project ofn)
endif()
endif()
+ if (CMAKE_GENERATOR MATCHES "Visual Studio")
+ # Visual Studio has problems with llvm-tblgen's native --write-if-changed
+ # behavior. Since it doesn't do restat optimizations anyway, just don't
+ # pass --write-if-changed there.
+ set(tblgen_change_flag)
+ else()
+ set(tblgen_change_flag "--write-if-changed")
+ endif()
+
# We need both _TABLEGEN_TARGET and _TABLEGEN_EXE in the DEPENDS list
# (both the target and the file) to have .inc files rebuilt on
# a tablegen change, as cmake does not propagate file-level dependencies
@@ -67,11 +76,11 @@ function(tablegen project ofn)
# dependency twice in the result file when
# ("${${project}_TABLEGEN_TARGET}" STREQUAL "${${project}_TABLEGEN_EXE}")
# but lets us having smaller and cleaner code here.
- add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${ofn}.tmp
- # Generate tablegen output in a temporary file.
+ add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
COMMAND ${${project}_TABLEGEN_EXE} ${ARGN} -I ${CMAKE_CURRENT_SOURCE_DIR}
${LLVM_TABLEGEN_FLAGS}
${LLVM_TARGET_DEFINITIONS_ABSOLUTE}
+ ${tblgen_change_flag}
${additional_cmdline}
# The file in LLVM_TARGET_DEFINITIONS may be not in the current
# directory and local_tds may not contain it, so we must
@@ -81,20 +90,9 @@ function(tablegen project ofn)
${LLVM_TARGET_DEFINITIONS_ABSOLUTE}
COMMENT "Building ${ofn}..."
)
- add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
- # Only update the real output file if there are any differences.
- # This prevents recompilation of all the files depending on it if there
- # aren't any.
- COMMAND ${CMAKE_COMMAND} -E copy_if_different
- ${CMAKE_CURRENT_BINARY_DIR}/${ofn}.tmp
- ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
- DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${ofn}.tmp
- COMMENT "Updating ${ofn}..."
- )
# `make clean' must remove all those generated files:
- set_property(DIRECTORY APPEND
- PROPERTY ADDITIONAL_MAKE_CLEAN_FILES ${ofn}.tmp ${ofn})
+ set_property(DIRECTORY APPEND PROPERTY ADDITIONAL_MAKE_CLEAN_FILES ${ofn})
set(TABLEGEN_OUTPUT ${TABLEGEN_OUTPUT} ${CMAKE_CURRENT_BINARY_DIR}/${ofn} PARENT_SCOPE)
set_source_files_properties(${CMAKE_CURRENT_BINARY_DIR}/${ofn} PROPERTIES
Modified: llvm/trunk/lib/TableGen/Main.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/TableGen/Main.cpp?rev=373664&r1=373663&r2=373664&view=diff
==============================================================================
--- llvm/trunk/lib/TableGen/Main.cpp (original)
+++ llvm/trunk/lib/TableGen/Main.cpp Thu Oct 3 14:22:28 2019
@@ -49,6 +49,9 @@ static cl::list<std::string>
MacroNames("D", cl::desc("Name of the macro to be defined"),
cl::value_desc("macro name"), cl::Prefix);
+static cl::opt<bool>
+WriteIfChanged("write-if-changed", cl::desc("Only write output if it changed"));
+
static int reportError(const char *ProgName, Twine Msg) {
errs() << ProgName << ": " << Msg;
errs().flush();
@@ -99,23 +102,41 @@ int llvm::TableGenMain(char *argv0, Tabl
if (Parser.ParseFile())
return 1;
- std::error_code EC;
- ToolOutputFile Out(OutputFilename, EC, sys::fs::OF_None);
- if (EC)
- return reportError(argv0, "error opening " + OutputFilename + ":" +
- EC.message() + "\n");
+ // Write output to memory.
+ std::string OutString;
+ raw_string_ostream Out(OutString);
+ if (MainFn(Out, Records))
+ return 1;
+
+ // Always write the depfile, even if the main output hasn't changed.
+ // If it's missing, Ninja considers the output dirty. If this was below
+ // the early exit below and someone deleted the .inc.d file but not the .inc
+ // file, tablegen would never write the depfile.
if (!DependFilename.empty()) {
if (int Ret = createDependencyFile(Parser, argv0))
return Ret;
}
- if (MainFn(Out.os(), Records))
- return 1;
+ if (WriteIfChanged) {
+ // Only updates the real output file if there are any differences.
+ // This prevents recompilation of all the files depending on it if there
+ // aren't any.
+ if (auto ExistingOrErr = MemoryBuffer::getFile(OutputFilename))
+ if (std::move(ExistingOrErr.get())->getBuffer() == Out.str())
+ return 0;
+ }
+
+ std::error_code EC;
+ ToolOutputFile OutFile(OutputFilename, EC, sys::fs::OF_None);
+ if (EC)
+ return reportError(argv0, "error opening " + OutputFilename + ":" +
+ EC.message() + "\n");
+ OutFile.os() << Out.str();
if (ErrorsPrinted > 0)
return reportError(argv0, Twine(ErrorsPrinted) + " errors.\n");
// Declare success.
- Out.keep();
+ OutFile.keep();
return 0;
}
Modified: llvm/trunk/utils/gn/secondary/llvm/utils/TableGen/tablegen.gni
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/gn/secondary/llvm/utils/TableGen/tablegen.gni?rev=373664&r1=373663&r2=373664&view=diff
==============================================================================
--- llvm/trunk/utils/gn/secondary/llvm/utils/TableGen/tablegen.gni (original)
+++ llvm/trunk/utils/gn/secondary/llvm/utils/TableGen/tablegen.gni Thu Oct 3 14:22:28 2019
@@ -64,11 +64,6 @@ template("tablegen") {
depfile = "$gen_output.d"
td_file = rebase_path(td_file, root_build_dir)
- # FIXME: The cmake build lets tablegen write to a temp file and then copies
- # it over the final output only if it has changed, for ninja's restat
- # optimization. Instead of doing that in cmake, llvm-tblgen should do this
- # itself. r330742 tried this, but it caused problems. Fix those and reland,
- # so that the gn build has the optimization too.
args = [
rebase_path(tblgen_executable, root_build_dir),
"-I",
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