[clang] 5eb2718 - [clang][OpenMP][DebugInfo] Debug support for variables in shared clause of OpenMP task construct
Alok Kumar Sharma via cfe-commits
cfe-commits at lists.llvm.org
Wed Dec 22 06:35:38 PST 2021
Author: Alok Kumar Sharma
Date: 2021-12-22T20:04:21+05:30
New Revision: 5eb271880c8fc59835797806ac44f736eaf3ddbd
URL: https://github.com/llvm/llvm-project/commit/5eb271880c8fc59835797806ac44f736eaf3ddbd
DIFF: https://github.com/llvm/llvm-project/commit/5eb271880c8fc59835797806ac44f736eaf3ddbd.diff
LOG: [clang][OpenMP][DebugInfo] Debug support for variables in shared clause of OpenMP task construct
Currently variables appearing inside shared clause of OpenMP task construct
are not visible inside lldb debugger.
After the current patch, lldb is able to show the variable
```
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x0000000000400934 a.out`.omp_task_entry. [inlined] .omp_outlined.(.global_tid.=0, .part_id.=0x000000000071f0d0, .privates.=0x000000000071f0e8, .copy_fn.=(a.out`.omp_task_privates_map. at testshared.cxx:8), .task_t.=0x000000000071f0c0, __context=0x000000000071f0f0) at testshared.cxx:10:34
7 else {
8 #pragma omp task shared(svar) firstprivate(n)
9 {
-> 10 printf("Task svar = %d\n", svar);
11 printf("Task n = %d\n", n);
12 svar = fib(n - 1);
13 }
(lldb) p svar
(int) $0 = 9
```
Reviewed By: djtodoro
Differential Revision: https://reviews.llvm.org/D115510
Added:
clang/test/OpenMP/debug_task_shared.c
Modified:
clang/lib/CodeGen/CGStmtOpenMP.cpp
clang/lib/CodeGen/CodeGenFunction.h
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index 2509de486671a..5677fce355d55 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -24,10 +24,13 @@
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/OpenMPKinds.h"
#include "clang/Basic/PrettyStackTrace.h"
+#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/Frontend/OpenMP/OMPConstants.h"
#include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
#include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Metadata.h"
#include "llvm/Support/AtomicOrdering.h"
using namespace clang;
using namespace CodeGen;
@@ -4431,6 +4434,53 @@ void CodeGenFunction::EmitOMPTaskBasedDirective(
UntiedLocalVars;
// Set proper addresses for generated private copies.
OMPPrivateScope Scope(CGF);
+ // Generate debug info for variables present in shared clause.
+ if (auto *DI = CGF.getDebugInfo()) {
+ llvm::SmallDenseMap<const VarDecl *, FieldDecl *> CaptureFields =
+ CGF.CapturedStmtInfo->getCaptureFields();
+ llvm::Value *ContextValue = CGF.CapturedStmtInfo->getContextValue();
+ if (CaptureFields.size() && ContextValue) {
+ unsigned CharWidth = CGF.getContext().getCharWidth();
+ // The shared variables are packed together as members of structure.
+ // So the address of each shared variable can be computed by adding
+ // offset of it (within record) to the base address of record. For each
+ // shared variable, debug intrinsic llvm.dbg.declare is generated with
+ // appropriate expressions (DIExpression).
+ // Ex:
+ // %12 = load %struct.anon*, %struct.anon** %__context.addr.i
+ // call void @llvm.dbg.declare(metadata %struct.anon* %12,
+ // metadata !svar1,
+ // metadata !DIExpression(DW_OP_deref))
+ // call void @llvm.dbg.declare(metadata %struct.anon* %12,
+ // metadata !svar2,
+ // metadata !DIExpression(DW_OP_plus_uconst, 8, DW_OP_deref))
+ for (auto It = CaptureFields.begin(); It != CaptureFields.end(); ++It) {
+ const VarDecl *SharedVar = It->first;
+ RecordDecl *CaptureRecord = It->second->getParent();
+ const ASTRecordLayout &Layout =
+ CGF.getContext().getASTRecordLayout(CaptureRecord);
+ unsigned Offset =
+ Layout.getFieldOffset(It->second->getFieldIndex()) / CharWidth;
+ (void)DI->EmitDeclareOfAutoVariable(SharedVar, ContextValue,
+ CGF.Builder, false);
+ llvm::Instruction &Last = CGF.Builder.GetInsertBlock()->back();
+ // Get the call dbg.declare instruction we just created and update
+ // its DIExpression to add offset to base address.
+ if (auto DDI = dyn_cast<llvm::DbgVariableIntrinsic>(&Last)) {
+ SmallVector<uint64_t, 8> Ops;
+ // Add offset to the base address if non zero.
+ if (Offset) {
+ Ops.push_back(llvm::dwarf::DW_OP_plus_uconst);
+ Ops.push_back(Offset);
+ }
+ Ops.push_back(llvm::dwarf::DW_OP_deref);
+ auto &Ctx = DDI->getContext();
+ llvm::DIExpression *DIExpr = llvm::DIExpression::get(Ctx, Ops);
+ Last.setOperand(2, llvm::MetadataAsValue::get(Ctx, DIExpr));
+ }
+ }
+ }
+ }
llvm::SmallVector<std::pair<const VarDecl *, Address>, 16> FirstprivatePtrs;
if (!Data.PrivateVars.empty() || !Data.FirstprivateVars.empty() ||
!Data.LastprivateVars.empty() || !Data.PrivateLocals.empty()) {
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 481ec2d606b11..f76ce8a6400d1 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -459,6 +459,11 @@ class CodeGenFunction : public CodeGenTypeCache {
/// Get the name of the capture helper.
virtual StringRef getHelperName() const { return "__captured_stmt"; }
+ /// Get the CaptureFields
+ llvm::SmallDenseMap<const VarDecl *, FieldDecl *> getCaptureFields() {
+ return CaptureFields;
+ }
+
private:
/// The kind of captured statement being generated.
CapturedRegionKind Kind;
diff --git a/clang/test/OpenMP/debug_task_shared.c b/clang/test/OpenMP/debug_task_shared.c
new file mode 100644
index 0000000000000..c3a23bc486324
--- /dev/null
+++ b/clang/test/OpenMP/debug_task_shared.c
@@ -0,0 +1,55 @@
+// This testcase checks emission of debug info for variables
+// inside shared clause of task construct.
+
+// REQUIRES: x86_64-linux
+
+// RUN: %clang_cc1 -debug-info-kind=constructor -DSHARED -x c -verify -triple x86_64-pc-linux-gnu -fopenmp -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK
+// RUN: %clang_cc1 -debug-info-kind=constructor -x c -verify -triple x86_64-pc-linux-gnu -fopenmp -emit-llvm %s -o - | FileCheck %s --check-prefix=NEG
+// expected-no-diagnostics
+
+// CHECK-LABEL: define internal i32 @.omp_task_entry.
+
+// CHECK-DAG: [[CONTEXT:%[0-9]+]] = load %struct.anon*, %struct.anon** %__context.addr.i, align 8
+// CHECK-DAG: call void @llvm.dbg.declare(metadata %struct.anon* [[CONTEXT]], metadata [[SHARE2:![0-9]+]], metadata !DIExpression(DW_OP_deref))
+// CHECK-DAG: call void @llvm.dbg.declare(metadata %struct.anon* [[CONTEXT]], metadata [[SHARE3:![0-9]+]], metadata !DIExpression(DW_OP_plus_uconst, 8, DW_OP_deref))
+// CHECK-DAG: call void @llvm.dbg.declare(metadata %struct.anon* [[CONTEXT]], metadata [[SHARE1:![0-9]+]], metadata !DIExpression(DW_OP_plus_uconst, 16, DW_OP_deref))
+
+// CHECK-DAG: [[SHARE2]] = !DILocalVariable(name: "share2"
+// CHECK-DAG: [[SHARE3]] = !DILocalVariable(name: "share3"
+// CHECK-DAG: [[SHARE1]] = !DILocalVariable(name: "share1"
+
+// NEG-LABEL: define internal i32 @.omp_task_entry.
+// NEG: [[CONTEXT:%[0-9]+]] = load %struct.anon*, %struct.anon** %__context.addr.i, align 8
+// NEG-NOT: call void @llvm.dbg.declare(metadata %struct.anon* [[CONTEXT]], metadata {{![0-9]+}}, metadata !DIExpression(DW_OP_deref))
+
+extern int printf(const char *, ...);
+
+int foo(int n) {
+ int share1 = 9, share2 = 11, share3 = 13, priv1, priv2, fpriv;
+ fpriv = n + 4;
+
+ if (n < 2)
+ return n;
+ else {
+#if SHARED
+#pragma omp task shared(share1, share2) private(priv1, priv2) firstprivate(fpriv) shared(share3)
+#else
+#pragma omp task private(priv1, priv2) firstprivate(fpriv)
+#endif
+ {
+ priv1 = n;
+ priv2 = n + 2;
+ share2 += share3;
+ printf("share1 = %d, share2 = %d, share3 = %d\n", share1, share2, share3);
+ share1 = priv1 + priv2 + fpriv + foo(n - 1) + share2 + share3;
+ }
+#pragma omp taskwait
+ return share1 + share2 + share3;
+ }
+}
+
+int main() {
+ int n = 10;
+ printf("foo(%d) = %d\n", n, foo(n));
+ return 0;
+}
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