snehasish created this revision.
snehasish added reviewers: tmsriram, davidxl.
Herald added subscribers: cfe-commits, dang.
Herald added a project: clang.
snehasish requested review of this revision.
This patch adds a command line flag for the machine function splitter
(added in rG94faadaca4e1
<https://reviews.llvm.org/rG94faadaca4e1704f674d2e9d4a1d25643b9ca52c>). The
command line reference has been updated
with the new flag and tests added to check the pass is run (requires
profile data) and that the driver has registered the correct option.
-fsplit-machine-functions
Split machine functions using profile information (x86-elf only)
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D87047
Files:
clang/docs/ClangCommandLineReference.rst
clang/include/clang/Basic/CodeGenOptions.def
clang/include/clang/Driver/Options.td
clang/lib/CodeGen/BackendUtil.cpp
clang/lib/Driver/ToolChains/Clang.cpp
clang/lib/Frontend/CompilerInvocation.cpp
clang/test/CodeGen/split-machine-functions.c
clang/test/Driver/fsplit-machine-functions.c
Index: clang/test/Driver/fsplit-machine-functions.c
===================================================================
--- /dev/null
+++ clang/test/Driver/fsplit-machine-functions.c
@@ -0,0 +1,4 @@
+// RUN: %clang -### -fsplit-machine-functions %s -c 2>&1 | FileCheck -check-prefix=CHECK-OPT %s
+// RUN: %clang -### -fsplit-machine-functions -fno-split-machine-functions %s -c 2>&1 | FileCheck -check-prefix=CHECK-NOOPT %s
+// CHECK-OPT: "-fsplit-machine-functions"
+// CHECK-NOOPT-NOT: "-fsplit-machine-functions"
Index: clang/test/CodeGen/split-machine-functions.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/split-machine-functions.c
@@ -0,0 +1,34 @@
+// REQUIRES: x86-registered-target
+
+// RUN: echo "foo" > %t.proftext
+// RUN: echo "# Func Hash:" >> %t.proftext
+// RUN: echo "11262309905" >> %t.proftext
+// RUN: echo "# Num Counters:" >> %t.proftext
+// RUN: echo "2" >> %t.proftext
+// RUN: echo "# Counter Values:" >> %t.proftext
+// RUN: echo "1000000" >> %t.proftext
+// RUN: echo "0" >> %t.proftext
+// RUN: llvm-profdata merge -o %t.profdata %t.proftext
+// RUN: %clang_cc1 -triple x86_64 -O3 -S -fprofile-instrument-use-path=%t.profdata -fsplit-machine-functions -o - < %s | FileCheck %s
+
+__attribute__((noinline)) int foo(int argc) {
+ if (argc % 2 == 0) {
+ exit(argc);
+ } else {
+ return argc + 1;
+ }
+}
+
+int main(int argc, char *argv[]) {
+ int total = 0;
+ for (int i = 0; i < 1000000; ++i) {
+ total += foo(argc);
+ }
+ printf("%d\n", total);
+}
+
+// CHECK: .section .text.hot.,"ax",@progbits
+// CHECK: foo:
+// CHECK: section .text.unlikely.foo,"ax",@progbits
+// CHECK: foo.cold:
+// CHECK: callq exit@PLT
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -998,6 +998,8 @@
Opts.UniqueInternalLinkageNames =
Args.hasArg(OPT_funique_internal_linkage_names);
+ Opts.SplitMachineFunctions = Args.hasArg(OPT_fsplit_machine_functions);
+
Opts.MergeFunctions = Args.hasArg(OPT_fmerge_functions);
Opts.NoUseJumpTables = Args.hasArg(OPT_fno_jump_tables);
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -4255,6 +4255,8 @@
options::OPT_fno_unique_section_names,
options::OPT_funique_basic_block_section_names,
options::OPT_fno_unique_basic_block_section_names,
+ options::OPT_fsplit_machine_functions,
+ options::OPT_fno_split_machine_functions,
options::OPT_mrestrict_it,
options::OPT_mno_restrict_it,
options::OPT_mstackrealign,
@@ -4905,6 +4907,10 @@
options::OPT_fno_unique_basic_block_section_names, false))
CmdArgs.push_back("-funique-basic-block-section-names");
+ if (Args.hasFlag(options::OPT_fsplit_machine_functions,
+ options::OPT_fno_split_machine_functions, false))
+ CmdArgs.push_back("-fsplit-machine-functions");
+
Args.AddLastArg(CmdArgs, options::OPT_finstrument_functions,
options::OPT_finstrument_functions_after_inlining,
options::OPT_finstrument_function_entry_bare);
Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -519,6 +519,7 @@
Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
Options.UniqueBasicBlockSectionNames =
CodeGenOpts.UniqueBasicBlockSectionNames;
+ Options.EnableMachineFunctionSplitter = CodeGenOpts.SplitMachineFunctions;
Options.TLSSize = CodeGenOpts.TLSSize;
Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
Options.ExplicitEmulatedTLS = CodeGenOpts.ExplicitEmulatedTLS;
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -1989,6 +1989,12 @@
defm unique_section_names : OptOutFFlag<"unique-section-names",
"", "Don't use unique names for text and data sections">;
+def fsplit_machine_functions : Flag <["-"], "fsplit-machine-functions">,
+ Group<f_Group>, Flags<[CC1Option]>,
+ HelpText<"Split machine functions using profile information (x86-elf only)">;
+def fno_split_machine_functions: Flag <["-"], "fno-split-machine-functions">,
+ Group<f_Group>;
+
defm strict_return : OptOutFFlag<"strict-return", "",
"Don't treat control flow paths that fall off the end of a non-void function as unreachable">;
Index: clang/include/clang/Basic/CodeGenOptions.def
===================================================================
--- clang/include/clang/Basic/CodeGenOptions.def
+++ clang/include/clang/Basic/CodeGenOptions.def
@@ -162,6 +162,7 @@
CODEGENOPT(NullPointerIsValid , 1, 0) ///< Assume Null pointer deference is defined.
CODEGENOPT(CorrectlyRoundedDivSqrt, 1, 0) ///< -cl-fp32-correctly-rounded-divide-sqrt
CODEGENOPT(UniqueInternalLinkageNames, 1, 0) ///< Internal Linkage symbols get unique names.
+CODEGENOPT(SplitMachineFunctions, 1, 0) ///< Split machine functions using profile information.
/// When false, this attempts to generate code as if the result of an
/// overflowing conversion matches the overflowing behavior of a target's native
Index: clang/docs/ClangCommandLineReference.rst
===================================================================
--- clang/docs/ClangCommandLineReference.rst
+++ clang/docs/ClangCommandLineReference.rst
@@ -2128,6 +2128,10 @@
Enables splitting of the LTO unit
+.. option:: -fsplit-machine-functions, -fno-split-machine-functions
+
+Split machine functions using profile information (x86-elf only)
+
.. option:: -fsplit-stack
.. option:: -fstack-clash-protection
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