[clang] [llvm] [llvm][vfs] Allow root directory remap (PR #83766)
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Sun Mar 3 21:49:07 PST 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
@llvm/pr-subscribers-llvm-support
Author: None (yelleyee)
<details>
<summary>Changes</summary>
Add a new feature allowing root(/) directory remap by breaking the
assumption that remap root must be a directory.
Now the config below will be allowed.
Directory-remap config of root(/) is not allowed in previous impl.
Config list below will cause assertion failure in
`uniqueOverlayTree`.
```json
'name': '/',
'type': 'directory-remap',
'external-contents': '/xxxx/xxx'
```
Assertion failed stack is attached below:
```
clang -cc1 -ferror-limit 19 -fcolor-diagnostics -o /dev/null -disable-free -emit-obj -x c a.c -tune-cpu generic -target-cpu x86-64 -triple x86_64-unknown-linux-gnu -resource-dir ///MY_ROOT///Source/llvm-project/build/lib/clang/18 -isystem ///MY_ROOT///Source/llvm-project/build/lib/clang/18/include -isystem /usr/local/include -isystem /usr/lib/gcc/x86_64-linux-gnu/9/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -std=gnu17 -fmath-errno -fno-implicit-modules -pic-level 2 -pic-is-pie -fgnuc-version=4.2.1 -ffp-contract=on -fno-experimental-relative-c++-abi-vtables -fno-file-reproducible -O0 -fdebug-compilation-dir=///MY_ROOT_1///gitWorkSpace/test -fcoverage-compilation-dir=///MY_ROOT_1///gitWorkSpace/test -faddrsig -mrelax-all -debugger-tuning=gdb -funwind-tables=2 -mconstructor-aliases -clear-ast-before-backend -main-file-name a.c -mframe-pointer=all -fdiagnostics-hotness-threshold=0 -fdiagnostics-misexpect-tolerance=0 -D __GCC_HAVE_DWARF2_CFI_ASM=1 -ivfsoverlay vfs.yaml
clang: ///MY_ROOT///llvm-project/llvm/lib/Support/VirtualFileSystem.cpp:1749: void llvm::vfs::RedirectingFileSystemParser::uniqueOverlayTree(llvm::vfs::RedirectingFileSystem*, llvm::vfs::RedirectingFileSystem::Entry*, llvm::vfs::RedirectingFileSystem::Entry*): Assertion `NewParentE && "Parent entry must exist"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0. Program arguments: clang -cc1 -ferror-limit 19 -fcolor-diagnostics -o /dev/null -disable-free -emit-obj -x c a.c -tune-cpu generic -target-cpu x86-64 -triple x86_64-unknown-linux-gnu -resource-dir ///MY_ROOT///Source/llvm-project/build/lib/clang/18 -isystem ///MY_ROOT///Source/llvm-project/build/lib/clang/18/include -isystem /usr/local/include -isystem /usr/lib/gcc/x86_64-linux-gnu/9/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -std=gnu17 -fmath-errno -fno-implicit-modules -pic-level 2 -pic-is-pie -fgnuc-version=4.2.1 -ffp-contract=on -fno-experimental-relative-c++-abi-vtables -fno-file-reproducible -O0 -fdebug-compilation-dir=///MY_ROOT_1///gitWorkSpace/test -fcoverage-compilation-dir=///MY_ROOT_1///gitWorkSpace/test -faddrsig -mrelax-all -debugger-tuning=gdb -funwind-tables=2 -mconstructor-aliases -clear-ast-before-backend -main-file-name a.c -mframe-pointer=all -fdiagnostics-hotness-threshold=0 -fdiagnostics-misexpect-tolerance=0 -D __GCC_HAVE_DWARF2_CFI_ASM=1 -ivfsoverlay vfs.yaml
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0 libLLVMSupport.so.16 0x00007f3786891a7c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 82
1 libLLVMSupport.so.16 0x00007f3786891e47
2 libLLVMSupport.so.16 0x00007f378688f72a llvm::sys::RunSignalHandlers() + 159
3 libLLVMSupport.so.16 0x00007f37868913b0
4 libc.so.6 0x00007f378606f090
5 libc.so.6 0x00007f378606f00b gsignal + 203
6 libc.so.6 0x00007f378604e859 abort + 299
7 libc.so.6 0x00007f378604e729
8 libc.so.6 0x00007f378605ffd6
9 libLLVMSupport.so.16 0x00007f37868320d2
10 libLLVMSupport.so.16 0x00007f3786834be3
11 libLLVMSupport.so.16 0x00007f3786822f00 llvm::vfs::RedirectingFileSystem::create(std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer>>, void (*)(llvm::SMDiagnostic const&, void*), llvm::StringRef, void*, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) + 994
12 libLLVMSupport.so.16 0x00007f3786825b06 llvm::vfs::getVFSFromYAML(std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer>>, void (*)(llvm::SMDiagnostic const&, void*), llvm::StringRef, void*, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) + 169
13 libclangFrontend.so.16 0x00007f378c6145c0 clang::createVFSFromOverlayFiles(llvm::ArrayRef<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>>, clang::DiagnosticsEngine&, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) + 520
14 libclangFrontend.so.16 0x00007f378c614392 clang::createVFSFromCompilerInvocation(clang::CompilerInvocation const&, clang::DiagnosticsEngine&, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) + 138
15 libclangFrontend.so.16 0x00007f378c6142e1 clang::createVFSFromCompilerInvocation(clang::CompilerInvocation const&, clang::DiagnosticsEngine&) + 75
16 libclangFrontend.so.16 0x00007f378c56f6b9 clang::CompilerInstance::createFileManager(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) + 175
17 libclangFrontend.so.16 0x00007f378c661b99 clang::FrontendAction::BeginSourceFile(clang::CompilerInstance&, clang::FrontendInputFile const&) + 4027
18 libclangFrontend.so.16 0x00007f378c5738f9 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 919
19 libclangFrontendTool.so.16 0x00007f379224adb6 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 937
20 clang 0x0000557f7ebde56b cc1_main(llvm::ArrayRef<char const*>, char const*, void*) + 1679
21 clang 0x0000557f7ebcb4ba
22 clang 0x0000557f7ebcbc8c clang_main(int, char**) + 1442
23 clang 0x0000557f7ec01ff5 main + 36
24 libc.so.6 0x00007f3786050083 __libc_start_main + 243
25 clang 0x0000557f7ebc99ce _start + 46
[1] 116965 abort clang -cc1 -ferror-limit 19 -fcolor-diagnostics -o /dev/null -disable-free -
```
---
Full diff: https://github.com/llvm/llvm-project/pull/83766.diff
4 Files Affected:
- (added) clang/test/VFS/Inputs/system-root-remap.yaml (+12)
- (added) clang/test/VFS/system-root-remap.c (+14)
- (modified) llvm/lib/Support/VirtualFileSystem.cpp (+18)
- (modified) llvm/unittests/Support/VirtualFileSystemTest.cpp (+42)
``````````diff
diff --git a/clang/test/VFS/Inputs/system-root-remap.yaml b/clang/test/VFS/Inputs/system-root-remap.yaml
new file mode 100644
index 00000000000000..43d25fcc952236
--- /dev/null
+++ b/clang/test/VFS/Inputs/system-root-remap.yaml
@@ -0,0 +1,12 @@
+{
+ 'version': 0,
+ 'use-external-names': false,
+ 'redirecting-with': 'redirect-only'
+ 'roots': [
+ {
+ 'name': '/',
+ 'type': 'directory-remap',
+ 'external-contents': 'EXTERNAL_DIR'
+ }
+ ]
+}
diff --git a/clang/test/VFS/system-root-remap.c b/clang/test/VFS/system-root-remap.c
new file mode 100644
index 00000000000000..f4168b75f29909
--- /dev/null
+++ b/clang/test/VFS/system-root-remap.c
@@ -0,0 +1,14 @@
+// RUN: mkdir -p %t
+// RUN: cd %t
+// RUN: sed -e "s at INPUT_DIR@%{/S:regex_replacement}/Inputs at g" -e "s at EXTERNAL_DIR@%{/t:regex_replacement}@g" %S/Inputs/system-root-remap.yaml > %t.yaml
+// RUN: mkdir -p %t%t
+// RUN: cp %S/Inputs/actual_header.h %t%t/not_real.h
+// RUN: mkdir -p %t%S
+// RUN: cp %s %t%S
+// RUN: %clang_cc1 -Werror -I . -vfsoverlay %t.yaml -fsyntax-only -working-directory=%t %s
+
+#include "not_real.h"
+
+void foo(void) {
+ bar();
+}
diff --git a/llvm/lib/Support/VirtualFileSystem.cpp b/llvm/lib/Support/VirtualFileSystem.cpp
index 051dd2a67d120f..1e18cbced9effd 100644
--- a/llvm/lib/Support/VirtualFileSystem.cpp
+++ b/llvm/lib/Support/VirtualFileSystem.cpp
@@ -1747,6 +1747,10 @@ class llvm::vfs::RedirectingFileSystemParser {
void uniqueOverlayTree(RedirectingFileSystem *FS,
RedirectingFileSystem::Entry *SrcE,
RedirectingFileSystem::Entry *NewParentE = nullptr) {
+ if (NewParentE) {
+ assert(NewParentE->getKind() == RedirectingFileSystem::EK_Directory &&
+ "NewParentE must be a directory entry or nullptr");
+ }
StringRef Name = SrcE->getName();
switch (SrcE->getKind()) {
case RedirectingFileSystem::EK_Directory: {
@@ -1756,12 +1760,26 @@ class llvm::vfs::RedirectingFileSystemParser {
// is parsed. This only leads to redundant walks, ignore it.
if (!Name.empty())
NewParentE = lookupOrCreateEntry(FS, Name, NewParentE);
+ if (NewParentE->getKind() != RedirectingFileSystem::EK_Directory) {
+ // Found non directory entry, no need to generate the left nodes.
+ break;
+ }
for (std::unique_ptr<RedirectingFileSystem::Entry> &SubEntry :
llvm::make_range(DE->contents_begin(), DE->contents_end()))
uniqueOverlayTree(FS, SubEntry.get(), NewParentE);
break;
}
case RedirectingFileSystem::EK_DirectoryRemap: {
+ // Root DirectoryRemap:
+ // name: "/"
+ // external-name: "xxxx"
+ if (!NewParentE) {
+ auto *DR = cast<RedirectingFileSystem::DirectoryRemapEntry>(SrcE);
+ FS->Roots.push_back(
+ std::make_unique<RedirectingFileSystem::DirectoryRemapEntry>(
+ Name, DR->getExternalContentsPath(), DR->getUseName()));
+ break;
+ }
assert(NewParentE && "Parent entry must exist");
auto *DR = cast<RedirectingFileSystem::DirectoryRemapEntry>(SrcE);
auto *DE = cast<RedirectingFileSystem::DirectoryEntry>(NewParentE);
diff --git a/llvm/unittests/Support/VirtualFileSystemTest.cpp b/llvm/unittests/Support/VirtualFileSystemTest.cpp
index d4abbb4345873c..0a77d8b13eca0e 100644
--- a/llvm/unittests/Support/VirtualFileSystemTest.cpp
+++ b/llvm/unittests/Support/VirtualFileSystemTest.cpp
@@ -1715,6 +1715,48 @@ TEST_F(VFSFromYAMLTest, MappedRoot) {
EXPECT_EQ(0, NumDiagnostics);
}
+TEST_F(VFSFromYAMLTest, MappedSysRoot) {
+ IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+ Lower->addDirectory("//root/foo/bar");
+ Lower->addRegularFile("//root/foo/bar/a");
+ IntrusiveRefCntPtr<vfs::FileSystem> FS =
+ getFromYAMLString("{ 'roots': [\n"
+ "{\n"
+ " 'type': 'directory-remap',\n"
+ " 'name': '/',\n"
+ " 'external-contents': '//root/foo/bar'\n"
+ "}\n"
+ "]\n"
+ "}",
+ Lower);
+ ASSERT_NE(FS.get(), nullptr);
+
+ IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
+ new vfs::OverlayFileSystem(Lower));
+ O->pushOverlay(FS);
+
+ // file
+ ErrorOr<vfs::Status> S = O->status("/a");
+ ASSERT_FALSE(S.getError());
+ EXPECT_EQ("//root/foo/bar/a", S->getName());
+ EXPECT_TRUE(S->ExposesExternalVFSPath);
+
+ ErrorOr<vfs::Status> SLower = O->status("//root/foo/bar/a");
+ EXPECT_EQ("//root/foo/bar/a", SLower->getName());
+ EXPECT_TRUE(S->equivalent(*SLower));
+ EXPECT_FALSE(SLower->ExposesExternalVFSPath);
+
+ // file after opening
+ auto OpenedF = O->openFileForRead("/a");
+ ASSERT_FALSE(OpenedF.getError());
+ auto OpenedS = (*OpenedF)->status();
+ ASSERT_FALSE(OpenedS.getError());
+ EXPECT_EQ("//root/foo/bar/a", OpenedS->getName());
+ EXPECT_TRUE(OpenedS->ExposesExternalVFSPath);
+
+ EXPECT_EQ(0, NumDiagnostics);
+}
+
TEST_F(VFSFromYAMLTest, RemappedDirectoryOverlay) {
IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
Lower->addDirectory("//root/foo");
``````````
</details>
https://github.com/llvm/llvm-project/pull/83766
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