https://github.com/MaggieYingYi updated https://github.com/llvm/llvm-project/pull/142409
>From b3dfc5edba4fbe8f219bc420ef8094a7815b4fe4 Mon Sep 17 00:00:00 2001 From: Ying Yi <ying...@sony.com> Date: Mon, 2 Jun 2025 10:21:22 +0100 Subject: [PATCH] [Frontend][PCH]-Add support for ignoring PCH options (-ignore-pch). Visual Studio has an argument to ignore all PCH related switches. clang-cl has also support option /Y-. Having the same option in clang would be helpful. This commit is to add support for ignoring PCH options (-ignore-pch). The commit includes: 1. Implement -ignore-pch as a Driver option. 2. Add a Driver test and a PCH test. 3. Add a section of -ignore-pch to user manual. 4. Add a release note for the new option '-ignore-pch'. Code reviewed by: Matheus Izvekov <mizve...@gmail.com> --- clang/docs/ReleaseNotes.rst | 2 + clang/docs/UsersManual.rst | 13 +++ clang/include/clang/Driver/Options.td | 3 + clang/lib/Driver/Driver.cpp | 9 ++ clang/lib/Driver/ToolChains/Clang.cpp | 5 +- clang/test/Driver/ignored-pch.cpp | 19 +++++ clang/test/PCH/Inputs/ignored-pch.h | 6 ++ clang/test/PCH/ignored-pch.c | 113 ++++++++++++++++++++++++++ 8 files changed, 168 insertions(+), 2 deletions(-) create mode 100644 clang/test/Driver/ignored-pch.cpp create mode 100644 clang/test/PCH/Inputs/ignored-pch.h create mode 100644 clang/test/PCH/ignored-pch.c diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index beed0da6883d6..c548c261453a6 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -339,6 +339,8 @@ New Compiler Flags - New option ``-Wnrvo`` added and disabled by default to warn about missed NRVO opportunities. +- New option ``-ignore-pch`` added to disable precompiled headers. It overrides ``-emit-pch`` and ``-include-pch``. (#GH142409, `PCHDocs <https://clang.llvm.org/docs/UsersManual.html#ignoring-a-pch-file>`_). + Deprecated Compiler Flags ------------------------- diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst index 62844f7e6a2fa..284a404026dfe 100644 --- a/clang/docs/UsersManual.rst +++ b/clang/docs/UsersManual.rst @@ -1458,6 +1458,19 @@ will be processed from the PCH file. Otherwise, Clang will report an error. ``test.h`` since ``test.h`` was included directly in the source file and not specified on the command line using ``-include-pch``. +Ignoring a PCH File +^^^^^^^^^^^^^^^^^^^ + +To ignore PCH options, a `-ignore-pch` option is passed to ``clang``: + +.. code-block:: console + + $ clang -x c-header test.h -Xclang -ignore-pch -o test.h.pch + $ clang -include-pch test.h.pch -Xclang -ignore-pch test.c -o test + +This option disables precompiled headers, overrides -emit-pch and -include-pch. +test.h.pch is not generated and not used as a prefix header. + Relocatable PCH Files ^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index 89c63fb3397d3..834aa708f5051 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -3348,6 +3348,9 @@ defm pch_codegen: OptInCC1FFlag<"pch-codegen", "Generate ", "Do not generate ", "code for uses of this PCH that assumes an explicit object file will be built for the PCH">; defm pch_debuginfo: OptInCC1FFlag<"pch-debuginfo", "Generate ", "Do not generate ", "debug info for types in an object file built from this PCH and do not generate them elsewhere">; +def ignore_pch : Flag<["-"], "ignore-pch">, Group<f_Group>, + Visibility<[ClangOption]>, + HelpText<"Disable precompiled headers, overrides -emit-pch and -include-pch">; def fimplicit_module_maps : Flag <["-"], "fimplicit-module-maps">, Group<f_Group>, Visibility<[ClangOption, CC1Option, CLOption]>, diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp index 80728daca03c9..a03fd508e006c 100644 --- a/clang/lib/Driver/Driver.cpp +++ b/clang/lib/Driver/Driver.cpp @@ -4331,6 +4331,15 @@ void Driver::handleArguments(Compilation &C, DerivedArgList &Args, YcArg = YuArg = nullptr; } + if (Args.hasArg(options::OPT_include_pch) && + (FinalPhase == phases::Preprocess || + Args.hasArg(options::OPT_ignore_pch))) { + // If only preprocessing or -ignore-pch is used, -include-pch is disabled. + // Since -emit-pch is CC1option, it will not be added to command argments if + // -ignore-pch is used. + Args.eraseArg(options::OPT_include_pch); + } + bool LinkOnly = phases::Link == FinalPhase && Inputs.size() > 0; for (auto &I : Inputs) { types::ID InputType = I.first; diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index d85cc4104389b..a3ca55e138ca2 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -5321,7 +5321,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, CmdArgs.push_back("-emit-module-interface"); else if (JA.getType() == types::TY_HeaderUnit) CmdArgs.push_back("-emit-header-unit"); - else + else if (!Args.hasArg(options::OPT_ignore_pch)) CmdArgs.push_back("-emit-pch"); } else if (isa<VerifyPCHJobAction>(JA)) { CmdArgs.push_back("-verify-pch"); @@ -5378,7 +5378,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, } else if (JA.getType() == types::TY_PP_Asm) { CmdArgs.push_back("-S"); } else if (JA.getType() == types::TY_AST) { - CmdArgs.push_back("-emit-pch"); + if (!Args.hasArg(options::OPT_ignore_pch)) + CmdArgs.push_back("-emit-pch"); } else if (JA.getType() == types::TY_ModuleFile) { CmdArgs.push_back("-module-file-info"); } else if (JA.getType() == types::TY_RewrittenObjC) { diff --git a/clang/test/Driver/ignored-pch.cpp b/clang/test/Driver/ignored-pch.cpp new file mode 100644 index 0000000000000..b237fc3cba57d --- /dev/null +++ b/clang/test/Driver/ignored-pch.cpp @@ -0,0 +1,19 @@ +// RUN: rm -rf %t +// RUN: mkdir -p %t + +// Create PCH without -ignore-pch. +// RUN: %clang -x c++-header %S/../Modules/Inputs/codegen-flags/foo.h -### 2>&1 | FileCheck %s -check-prefix=CHECK-EMIT-PCH +// RUN: %clang -x c++-header %S/../Modules/Inputs/codegen-flags/foo.h -o %t/foo.h.pch +// RUN: %clang %s -include-pch %t/foo.h.pch -### 2>&1 | FileCheck %s -check-prefix=CHECK-INCLUDE-PCH +// RUN: %clang %s -emit-ast -include-pch %t/foo.h.pch -### 2>&1 | FileCheck %s -check-prefixes=CHECK-EMIT-PCH,CHECK-INCLUDE-PCH + + +// Create PCH with -ignore-pch. +// RUN: %clang -x c++-header -ignore-pch %S/../Modules/Inputs/codegen-flags/foo.h -### 2>&1 | FileCheck %s -check-prefix=CHECK-IGNORE-PCH +// RUN: %clang %s -ignore-pch -include-pch %t/foo.h.pch -### 2>&1 | FileCheck %s -check-prefix=CHECK-IGNORE-PCH +// RUN: %clang %s -ignore-pch -emit-ast -include-pch %t/foo.h.pch -### 2>&1 | FileCheck %s -check-prefix=CHECK-IGNORE-PCH + +// CHECK-EMIT-PCH: -emit-pch +// CHECK-INCLUDE-PCH: -include-pch +// CHECK-IGNORE-PCH-NOT: -emit-pch +// CHECK-IGNORE-PCH-NOT: -include-pch diff --git a/clang/test/PCH/Inputs/ignored-pch.h b/clang/test/PCH/Inputs/ignored-pch.h new file mode 100644 index 0000000000000..56047037c331f --- /dev/null +++ b/clang/test/PCH/Inputs/ignored-pch.h @@ -0,0 +1,6 @@ +#ifndef IGNORED_PCH_H +#define IGNORED_PCH_H +inline int f() { + return 42; +} +#endif // IGNORED_PCH_H diff --git a/clang/test/PCH/ignored-pch.c b/clang/test/PCH/ignored-pch.c new file mode 100644 index 0000000000000..5b64582cba618 --- /dev/null +++ b/clang/test/PCH/ignored-pch.c @@ -0,0 +1,113 @@ +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -o %t.ll +// RUN: ls %t.pch | FileCheck --check-prefix=CHECK-PCH %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -o %t.pch +// RUN: %clang %s -emit-ast -include-pch %t.pch -o %t.ll +// RUN: ls %t.pch | FileCheck --check-prefix=CHECK-PCH %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// Check that -ignore-pch causes -emit-pch and -include-pch options to be ignored. +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -ignore-pch -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH-ERROR %s +// RUN: ls %t.ll 2>&1 | FileCheck --check-prefix=CHECK-OBJ %s + +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -emit-ast %s -include-pch %t.pch -ignore-pch -o %t.ll +// RUN: not ls %t.ll 2>&1 | FileCheck --check-prefix=CHECK-OBJ-ERROR %s + +// Check that -ignore-pch works for multiple PCH related options. +// Test with -building-pch-with-obj. +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -Xclang -building-pch-with-obj -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -ignore-pch -Xclang -building-pch-with-obj -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH-ERROR %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// Test with -fallow-pch-with-compiler-errors. +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -Xclang -fallow-pch-with-compiler-errors -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -ignore-pch -Xclang -fallow-pch-with-compiler-errors -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH-ERROR %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// Test with -fallow-pch-with-different-modules-cache-path. +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -Xclang -fallow-pch-with-different-modules-cache-path -o %t.pch +// RUN: %clang -S -emit-llvm %s -ignore-pch -include-pch %t.pch -Xclang -fallow-pch-with-different-modules-cache-path -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH-ERROR %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// Test with -fpch-codegen. +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -fpch-codegen -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -ignore-pch -fpch-codegen -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH-ERROR %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// Test with -fpch-debuginfo. +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -fpch-debuginfo -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -ignore-pch -fpch-debuginfo -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// Test with -fpch-instantiate-templates. +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -fpch-instantiate-templates -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -ignore-pch -fpch-instantiate-templates -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// Test with -fno-pch-timestamp. +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -Xclang -fno-pch-timestamp -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -ignore-pch -Xclang -fno-pch-timestamp -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// Test with -fno-validate-pch. +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -Xclang -fno-validate-pch -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -ignore-pch -Xclang -fno-validate-pch -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// Test with -relocatable-pch. +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -relocatable-pch -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -ignore-pch -relocatable-pch -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + +// Test with -pch-through-hdrstop-create/-pch-through-hdrstop-use +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -ignore-pch -Xclang -pch-through-hdrstop-create -o %t.pch +// RUN: %clang -S -emit-llvm %s -include-pch %t.pch -ignore-pch -Xclang -pch-through-hdrstop-use -o %t.ll +// RUN: not ls %t.pch 2>&1 | FileCheck --check-prefix=CHECK-PCH %s +// RUN: ls %t.ll | FileCheck --check-prefix=CHECK-OBJ %s + + +// Test with AST dump output: +// RUN: rm -rf %t.pch %t.ll +// RUN: %clang -x c-header %S/Inputs/ignored-pch.h -o %t.pch +// RUN: %clang %s -include-pch %t.pch -Xclang -ast-dump-all -c | FileCheck --check-prefix=CHECK-AST-PCH %s +// RUN: %clang %s -include-pch %t.pch -ignore-pch -Xclang -ast-dump-all -c | FileCheck --check-prefix=CHECK-AST %s + +// CHECK-PCH: ignored-pch.c.{{.*}}.pch +// CHECK-OBJ: ignored-pch.c.{{.*}}.ll +// CHECK-PCH-ERROR: ignored-pch.c.{{.*}}.pch{{'?}}: No such file or directory +// CHECK-OBJ-ERROR: ignored-pch.c.{{.*}}.ll{{'?}}: No such file or directory +// CHECK-AST-PCH: <undeserialized declarations> +// CHECK-AST-NOT: <undeserialized declarations> + +#pragma hdrstop +#include "Inputs/ignored-pch.h" +int main() { + return f(); +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
