https://github.com/sheredom updated
https://github.com/llvm/llvm-project/pull/106577
>From 588d45ef291997bc6df487ce9562768d92bff14d Mon Sep 17 00:00:00 2001
From: Neil Henning <neil.henn...@epicgames.com>
Date: Thu, 29 Aug 2024 13:15:49 +0100
Subject: [PATCH] Make PCH's respect any VFS specified.
We want to be able to generate a PCH against one file-system path, and
then re-use that PCH when the file-system path is different (but the
sources are the same). We also do not know when generating the PCH what
the destination file-system path will be, so what we want to be able to
do is:
- When generating a PCH map the original directory to some fake
directory. You could imagine `D:/Foo` being mapped to `Z:/Foo` for
instance.
- Then when consuming a PCH, we want to be able to use a different
mapping to map `Z:/Foo` to `D:/Some/Other/Machines/Foo` for instance.
This will let us generate and share PCHs to speed up compile time for
our users.
To enable this we've made PCH generation respect any specified
vfsoverlay, such that it will remap the paths in the PCH accordingly.
We've also made `-verify-pch` respect the
`-fvalidate-ast-input-files-content` option so that we can force
verification of inputs.
---
clang/lib/Frontend/FrontendActions.cpp | 3 ++-
clang/lib/Serialization/ASTWriter.cpp | 18 +++++++++++++
clang/test/PCH/verify_no_timestamp.c | 8 ++++++
.../Inputs/vfsoverlay-directory-remap.yaml | 9 +++++++
clang/test/VFS/remap-to-fake.c | 27 +++++++++++++++++++
llvm/cmake/config-ix.cmake | 1 +
6 files changed, 65 insertions(+), 1 deletion(-)
create mode 100644 clang/test/PCH/verify_no_timestamp.c
create mode 100644 clang/test/VFS/Inputs/vfsoverlay-directory-remap.yaml
create mode 100644 clang/test/VFS/remap-to-fake.c
diff --git a/clang/lib/Frontend/FrontendActions.cpp
b/clang/lib/Frontend/FrontendActions.cpp
index 64f90c493c1055..0fec806f714d83 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -348,7 +348,8 @@ void VerifyPCHAction::ExecuteAction() {
DisableValidationForModuleKind::None,
/*AllowASTWithCompilerErrors*/ false,
/*AllowConfigurationMismatch*/ true,
- /*ValidateSystemInputs*/ true));
+ /*ValidateSystemInputs*/ true,
+ CI.getHeaderSearchOpts().ValidateASTInputFilesContent));
Reader->ReadAST(getCurrentFile(),
Preamble ? serialization::MK_Preamble
diff --git a/clang/lib/Serialization/ASTWriter.cpp
b/clang/lib/Serialization/ASTWriter.cpp
index 008bf571f847dc..28787f3ee88281 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -4781,6 +4781,24 @@ bool
ASTWriter::PreparePathForOutput(SmallVectorImpl<char> &Path) {
Changed = true;
}
+ // If we are generating a normal PCH (EG. not a C++ module).
+ if (!WritingModule) {
+ // Use the vfs overlay if it exists to translate paths.
+ auto &FileSys =
+ Context->getSourceManager().getFileManager().getVirtualFileSystem();
+ if (auto *RFS = dyn_cast<llvm::vfs::RedirectingFileSystem>(&FileSys)) {
+ if (auto Result = RFS->lookupPath(StringRef(Path.data(), Path.size()))) {
+ if (std::optional<StringRef> Redirect = Result->getExternalRedirect())
{
+ const char *data = Redirect->data();
+ const size_t size = Redirect->size();
+ Path.resize(size);
+ Path.assign(data, data + size);
+ Changed = true;
+ }
+ }
+ }
+ }
+
return Changed;
}
diff --git a/clang/test/PCH/verify_no_timestamp.c
b/clang/test/PCH/verify_no_timestamp.c
new file mode 100644
index 00000000000000..8aca76cf77c449
--- /dev/null
+++ b/clang/test/PCH/verify_no_timestamp.c
@@ -0,0 +1,8 @@
+// RUN: echo 'int SomeFunc() { return 42; }' > %t.h
+// RUN: %clang_cc1 -Werror -fno-pch-timestamp
-fvalidate-ast-input-files-content -emit-pch -o "%t.pch" %t.h
+
+// Now change the source file, which should cause the verifier to fail with
content mismatch.
+// RUN: echo 'int SomeFunc() { return 13; }' > %t.h
+// RUN: not %clang_cc1 -fno-pch-timestamp -fvalidate-ast-input-files-content
-verify-pch %t.pch 2>&1 | FileCheck %s -DT=%t
+
+// CHECK: fatal error: file '[[T]].h' has been modified since the precompiled
header '[[T]].pch' was built: content changed
diff --git a/clang/test/VFS/Inputs/vfsoverlay-directory-remap.yaml
b/clang/test/VFS/Inputs/vfsoverlay-directory-remap.yaml
new file mode 100644
index 00000000000000..3cb279a08fae14
--- /dev/null
+++ b/clang/test/VFS/Inputs/vfsoverlay-directory-remap.yaml
@@ -0,0 +1,9 @@
+{
+ 'version': 0,
+ 'roots': [
+ { 'name': 'FROM_DIR',
+ 'type': 'directory-remap',
+ 'external-contents': 'TO_DIR'
+ }
+ ]
+}
diff --git a/clang/test/VFS/remap-to-fake.c b/clang/test/VFS/remap-to-fake.c
new file mode 100644
index 00000000000000..85572e0120ae60
--- /dev/null
+++ b/clang/test/VFS/remap-to-fake.c
@@ -0,0 +1,27 @@
+// RUN: split-file %s %t
+// RUN: sed -e "s@FROM_DIR@%{/t:regex_replacement}/From@g" -e
"s@TO_DIR@%{/t:regex_replacement}/Fake@g"
%S/Inputs/vfsoverlay-directory-remap.yaml > %t/to-fake.yaml
+// RUN: sed -e "s@FROM_DIR@%{/t:regex_replacement}/Fake@g" -e
"s@TO_DIR@%{/t:regex_replacement}/To@g"
%S/Inputs/vfsoverlay-directory-remap.yaml > %t/from-fake.yaml
+
+// RUN: %clang_cc1 -Werror -fno-pch-timestamp
-fvalidate-ast-input-files-content -ivfsoverlay %t/to-fake.yaml -emit-pch -o
"%t.pch" %t/From/../From/B.h
+
+// Remove the `From` directory as we don't want to accidentally find that
source if the PCH hasn't remapped using the VFS!
+// RUN: rm -rf %t/From
+
+// The PCH will be invalid because the `Fake` directory does not exist.
+// RUN: not %clang_cc1 -fno-pch-timestamp -fvalidate-ast-input-files-content
-verify-pch %t.pch
+
+// But if we specify the correct VFS overlay it'll verify clean.
+// RUN: %clang_cc1 -fno-pch-timestamp -fvalidate-ast-input-files-content
-verify-pch -ivfsoverlay %t/from-fake.yaml %t.pch
+
+// RUN: %clang_cc1 -fno-pch-timestamp -fvalidate-ast-input-files-content
-Werror -I %t/To -ivfsoverlay %t/from-fake.yaml -include-pch "%t.pch"
-emit-llvm -C %t/Test.c -o %t.o
+
+//--- From/B.h
+#pragma once
+int SomeFunc() { return 13; }
+//--- To/B.h
+#pragma once
+int SomeFunc() { return 13; }
+//--- Test.c
+#include "B.h"
+
+int UseSomeFunc() { return SomeFunc(); }
diff --git a/llvm/cmake/config-ix.cmake b/llvm/cmake/config-ix.cmake
index 3707ca824f6e9c..af76d500a9b11c 100644
--- a/llvm/cmake/config-ix.cmake
+++ b/llvm/cmake/config-ix.cmake
@@ -131,6 +131,7 @@ if(LLVM_ENABLE_ZLIB)
elseif(NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
find_package(ZLIB)
endif()
+
if(ZLIB_FOUND)
# Check if zlib we found is usable; for example, we may have found a 32-bit
# library on a 64-bit system which would result in a link-time failure.
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