From 5eb271880c8fc59835797806ac44f736eaf3ddbd Mon Sep 17 00:00:00 2001 From: Alok Kumar Sharma Date: Wed, 22 Dec 2021 19:56:37 +0530 Subject: [PATCH] [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 --- clang/lib/CodeGen/CGStmtOpenMP.cpp | 50 +++++++++++++++++++++++++++++++ clang/lib/CodeGen/CodeGenFunction.h | 5 ++++ clang/test/OpenMP/debug_task_shared.c | 55 +++++++++++++++++++++++++++++++++++ 3 files changed, 110 insertions(+) create mode 100644 clang/test/OpenMP/debug_task_shared.c diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp index 2509de4..5677fce 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 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(&Last)) { + SmallVector 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, 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 481ec2d..f76ce8a 100644 --- a/clang/lib/CodeGen/CodeGenFunction.h +++ b/clang/lib/CodeGen/CodeGenFunction.h @@ -459,6 +459,11 @@ public: /// Get the name of the capture helper. virtual StringRef getHelperName() const { return "__captured_stmt"; } + /// Get the CaptureFields + llvm::SmallDenseMap 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 0000000..c3a23bc --- /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; +} -- 2.7.4