[clang] Use VFS for -fopenmp-host-ir-file-path

[jansvoboda11]

This is a follow-up to #150124. This PR makes it so that the -fopenmp-host-ir-file-path respects VFS overlays, like any other input file.

[llvmbot]

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Author: Jan Svoboda (jansvoboda11)

Changes

This is a follow-up to #150124. This PR makes it so that the -fopenmp-host-ir-file-path respects VFS overlays, like any other input file.

---

Full diff: https://github.com/llvm/llvm-project/pull/156727.diff

5 Files Affected:

• (modified) clang/lib/CodeGen/CGOpenMPRuntime.cpp (+2-1)
• (modified) clang/lib/CodeGen/CodeGenModule.cpp (+1-2)
• (added) clang/test/OpenMP/host-ir-file-vfs.c (+33)
• (modified) llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h (+6-1)
• (modified) llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp (+4-2)

diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.cpp b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
index b38eb54036e60..68ecf6ae347c3 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -1038,7 +1038,8 @@ CGOpenMPRuntime::CGOpenMPRuntime(CodeGenModule &CGM)
       /*HasRequiresReverseOffload*/ false, /*HasRequiresUnifiedAddress*/ false,
       hasRequiresUnifiedSharedMemory(), /*HasRequiresDynamicAllocators*/ false);
   OMPBuilder.initialize();
-  OMPBuilder.loadOffloadInfoMetadata(CGM.getLangOpts().OpenMPIsTargetDevice
+  OMPBuilder.loadOffloadInfoMetadata(*CGM.getFileSystem(),
+                                     CGM.getLangOpts().OpenMPIsTargetDevice
                                          ? CGM.getLangOpts().OMPHostIRFile
                                          : StringRef{});
   OMPBuilder.setConfig(Config);
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index f1ddaa875f3e4..89fc9baa73d98 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -582,8 +582,7 @@ void CodeGenModule::createOpenCLRuntime() {
 }
 
 void CodeGenModule::createOpenMPRuntime() {
-  if (!LangOpts.OMPHostIRFile.empty() &&
-      !llvm::sys::fs::exists(LangOpts.OMPHostIRFile))
+  if (!LangOpts.OMPHostIRFile.empty() && !FS->exists(LangOpts.OMPHostIRFile))
     Diags.Report(diag::err_omp_host_ir_file_not_found)
         << LangOpts.OMPHostIRFile;
 
diff --git a/clang/test/OpenMP/host-ir-file-vfs.c b/clang/test/OpenMP/host-ir-file-vfs.c
new file mode 100644
index 0000000000000..394d8fbcc94ac
--- /dev/null
+++ b/clang/test/OpenMP/host-ir-file-vfs.c
@@ -0,0 +1,33 @@
+// This test checks that the OpenMP host IR file goes through VFS overlays.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+// RUN: sed -e "s|DIR|%/t|g" %t/vfs.json.in > %t/vfs.json
+// RUN: %clang_cc1 -fopenmp-simd -triple i386-unknown-unknown -fopenmp-targets=i386-pc-linux-gnu -emit-llvm-bc %t/host.c -o %t/host.bc
+
+// RUN: %clang_cc1 -fopenmp-simd -triple i386-unknown-unknown -fopenmp-targets=i386-pc-linux-gnu -emit-llvm %t/device.c -o - \
+// RUN:   -fopenmp-is-target-device -fopenmp-host-ir-file-path %t/virtual/host.bc -ivfsoverlay %t/vfs.json -verify
+
+//--- vfs.json.in
+{
+  'version': 0,
+  'use-external-names': true,
+  'roots': [
+    {
+      'name': 'DIR/virtual',
+      'type': 'directory',
+      'contents': [
+        {
+          'name': 'host.bc',
+          'type': 'file',
+          'external-contents': 'DIR/host.bc'
+        }
+      ]
+    }
+  ]
+}
+
+//--- host.c
+//--- device.c
+// expected-no-diagnostics
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h b/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
index 1050e3d8b08dd..cc1177ba3d11c 100644
--- a/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
+++ b/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
@@ -39,6 +39,10 @@ class Loop;
 class LoopAnalysis;
 class LoopInfo;
 
+namespace vfs {
+class FileSystem;
+} // namespace vfs
+
 /// Move the instruction after an InsertPoint to the beginning of another
 /// BasicBlock.
 ///
@@ -3629,7 +3633,8 @@ class OpenMPIRBuilder {
   /// \param HostFilePath The path to the host IR file,
   /// used to load in offload metadata for the device, allowing host and device
   /// to maintain the same metadata mapping.
-  LLVM_ABI void loadOffloadInfoMetadata(StringRef HostFilePath);
+  LLVM_ABI void loadOffloadInfoMetadata(vfs::FileSystem &VFS,
+                                        StringRef HostFilePath);
 
   /// Gets (if variable with the given name already exist) or creates
   /// internal global variable with the specified Name. The created variable has
diff --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index 03ea58318d4a9..f2ba0f65fd464 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -50,6 +50,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
@@ -10523,11 +10524,12 @@ void OpenMPIRBuilder::loadOffloadInfoMetadata(Module &M) {
   }
 }
 
-void OpenMPIRBuilder::loadOffloadInfoMetadata(StringRef HostFilePath) {
+void OpenMPIRBuilder::loadOffloadInfoMetadata(vfs::FileSystem &VFS,
+                                              StringRef HostFilePath) {
   if (HostFilePath.empty())
     return;
 
-  auto Buf = MemoryBuffer::getFile(HostFilePath);
+  auto Buf = VFS.getBufferForFile(HostFilePath);
   if (std::error_code Err = Buf.getError()) {
     report_fatal_error(("error opening host file from host file path inside of "
                         "OpenMPIRBuilder: " +

[alexey-bataev]

This it should be executed on linux only. Can we try to avoid using rm, sed, etc?

[jansvoboda11]

Why should this test be executed on Linux only? The Clang arguments were taken from clang/test/OpenMP/simd_codegen.cpp that doesn't have any REQUIRES lines, so I don't think this is testing something specific to the host platform. If the reason is the rm and sed commands you mention, I believe those are guaranteed to be available on all platforms where we support running tests - for example on Windows, we require Git bash tools to be installed.