[clang] 82e537a - [Clang][OpenMP] Fixed an issue that clang crashed when compiling OpenMP program in device only mode without host IR

[Shilei Tian via cfe-commits]

Author: Shilei Tian
Date: 2021-01-19T14:18:42-05:00
New Revision: 82e537a9d28a2c18bd1637e2eac0e0af658ed829

URL: https://github.com/llvm/llvm-project/commit/82e537a9d28a2c18bd1637e2eac0e0af658ed829
DIFF: https://github.com/llvm/llvm-project/commit/82e537a9d28a2c18bd1637e2eac0e0af658ed829.diff

LOG: [Clang][OpenMP] Fixed an issue that clang crashed when compiling OpenMP program in device only mode without host IR

D94745 rewrites the `deviceRTLs` using OpenMP and compiles it by directly
calling the device compilation. `clang` crashes because entry in
`OffloadEntriesDeviceGlobalVar` is unintialized. Current design supposes the
device compilation can only be invoked after host compilation with the host IR
such that `clang` can initialize `OffloadEntriesDeviceGlobalVar` from host IR.
This avoids us using device compilation directly, especially when we only have
code wrapped into `declare target` which are all device code. The same issue
also exists for `OffloadEntriesInfoManager`.

In this patch, we simply initialized an entry if it is not in the maps. Not sure
we need an option to tell the device compiler that it is invoked standalone.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D94871

Added: 
    clang/test/OpenMP/declare_target_device_only_compilation.cpp

Modified: 
    clang/lib/CodeGen/CGOpenMPRuntime.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CGOpenMPRuntime.cpp b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
index a3b24039365b..17fa56fb06c8 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -2941,16 +2941,12 @@ void CGOpenMPRuntime::OffloadEntriesInfoManagerTy::
   // If we are emitting code for a target, the entry is already initialized,
   // only has to be registered.
   if (CGM.getLangOpts().OpenMPIsDevice) {
-    if (!hasTargetRegionEntryInfo(DeviceID, FileID, ParentName, LineNum)) {
-      unsigned DiagID = CGM.getDiags().getCustomDiagID(
-          DiagnosticsEngine::Error,
-          "Unable to find target region on line '%0' in the device code.");
-      CGM.getDiags().Report(DiagID) << LineNum;
-      return;
-    }
+    // This could happen if the device compilation is invoked standalone.
+    if (!hasTargetRegionEntryInfo(DeviceID, FileID, ParentName, LineNum))
+      initializeTargetRegionEntryInfo(DeviceID, FileID, ParentName, LineNum,
+                                      OffloadingEntriesNum);
     auto &Entry =
         OffloadEntriesTargetRegion[DeviceID][FileID][ParentName][LineNum];
-    assert(Entry.isValid() && "Entry not initialized!");
     Entry.setAddress(Addr);
     Entry.setID(ID);
     Entry.setFlags(Flags);
@@ -3017,9 +3013,10 @@ void CGOpenMPRuntime::OffloadEntriesInfoManagerTy::
                                      OMPTargetGlobalVarEntryKind Flags,
                                      llvm::GlobalValue::LinkageTypes Linkage) {
   if (CGM.getLangOpts().OpenMPIsDevice) {
+    // This could happen if the device compilation is invoked standalone.
+    if (!hasDeviceGlobalVarEntryInfo(VarName))
+      initializeDeviceGlobalVarEntryInfo(VarName, Flags, OffloadingEntriesNum);
     auto &Entry = OffloadEntriesDeviceGlobalVar[VarName];
-    assert(Entry.isValid() && Entry.getFlags() == Flags &&
-           "Entry not initialized!");
     assert((!Entry.getAddress() || Entry.getAddress() == Addr) &&
            "Resetting with the new address.");
     if (Entry.getAddress() && hasDeviceGlobalVarEntryInfo(VarName)) {

diff  --git a/clang/test/OpenMP/declare_target_device_only_compilation.cpp b/clang/test/OpenMP/declare_target_device_only_compilation.cpp
new file mode 100644
index 000000000000..280959540306
--- /dev/null
+++ b/clang/test/OpenMP/declare_target_device_only_compilation.cpp
@@ -0,0 +1,15 @@
+//==========================================================================///
+// RUN: %clang -S -target powerpc64le-ibm-linux-gnu -fopenmp -fopenmp-targets=powerpc64le-ibm-linux-gnu -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang -S -target i386-pc-linux-gnu -fopenmp -fopenmp-targets=i386-pc-linux-gnu -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang -S -target x86_64-unknown-linux-gnu -fopenmp -fopenmp-targets=x86_64-unknown-linux-gnu -emit-llvm %s -o - | FileCheck %s
+// expected-no-diagnostics
+
+#pragma omp declare target
+#pragma omp begin declare variant match(device={kind(nohost)})
+int G1;
+#pragma omp end declare variant
+#pragma omp end declare target
+
+// CHECK: @[[G:.+]] = hidden {{.*}}global i32 0, align 4
+// CHECK: !omp_offload.info = !{!0}
+// CHECK: !0 = !{i32 1, !"[[G]]", i32 0, i32 0}