[Lldb-commits] [lldb] f56cb52 - [DEBUGINFO] [LLDB] Add support for generating debug-info for structured bindings of structs and arrays
Shafik Yaghmour via lldb-commits
lldb-commits at lists.llvm.org
Thu Feb 17 11:14:21 PST 2022
Author: Shafik Yaghmour
Date: 2022-02-17T11:14:14-08:00
New Revision: f56cb520d8554ca42a215e82ecfa58d0b6c178e4
URL: https://github.com/llvm/llvm-project/commit/f56cb520d8554ca42a215e82ecfa58d0b6c178e4
DIFF: https://github.com/llvm/llvm-project/commit/f56cb520d8554ca42a215e82ecfa58d0b6c178e4.diff
LOG: [DEBUGINFO] [LLDB] Add support for generating debug-info for structured bindings of structs and arrays
Currently we are not emitting debug-info for all cases of structured bindings a
C++17 feature which allows us to bind names to subobjects in an initializer.
A structured binding is represented by a DecompositionDecl AST node and the
binding are represented by a BindingDecl. It looks the original implementation
only covered the tuple like case which be represented by a DeclRefExpr which
contains a VarDecl.
If the binding is to a subobject of the struct the binding will contain a
MemberExpr and in the case of arrays it will contain an ArraySubscriptExpr.
This PR adds support emitting debug-info for the MemberExpr and ArraySubscriptExpr
cases as well as llvm and lldb tests for these cases as well as the tuple case.
Differential Revision: https://reviews.llvm.org/D119178
Added:
clang/test/CodeGenCXX/debug-info-structured-binding.cpp
lldb/test/API/lang/cpp/structured-binding/Makefile
lldb/test/API/lang/cpp/structured-binding/TestStructuredBinding.py
lldb/test/API/lang/cpp/structured-binding/main.cpp
Modified:
clang/lib/CodeGen/CGDebugInfo.cpp
clang/lib/CodeGen/CGDebugInfo.h
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index d75b5a1a9d125..2203f0aec5c7c 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -4635,11 +4635,103 @@ llvm::DILocalVariable *CGDebugInfo::EmitDeclare(const VarDecl *VD,
return D;
}
+llvm::DILocalVariable *CGDebugInfo::EmitDeclare(const BindingDecl *BD,
+ llvm::Value *Storage,
+ llvm::Optional<unsigned> ArgNo,
+ CGBuilderTy &Builder,
+ const bool UsePointerValue) {
+ assert(CGM.getCodeGenOpts().hasReducedDebugInfo());
+ assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
+ if (BD->hasAttr<NoDebugAttr>())
+ return nullptr;
+
+ // Skip the tuple like case, we don't handle that here
+ if (isa<DeclRefExpr>(BD->getBinding()))
+ return nullptr;
+
+ llvm::DIFile *Unit = getOrCreateFile(BD->getLocation());
+ llvm::DIType *Ty = getOrCreateType(BD->getType(), Unit);
+
+ // If there is no debug info for this type then do not emit debug info
+ // for this variable.
+ if (!Ty)
+ return nullptr;
+
+ auto Align = getDeclAlignIfRequired(BD, CGM.getContext());
+ unsigned AddressSpace = CGM.getContext().getTargetAddressSpace(BD->getType());
+
+ SmallVector<uint64_t, 3> Expr;
+ AppendAddressSpaceXDeref(AddressSpace, Expr);
+
+ // Clang stores the sret pointer provided by the caller in a static alloca.
+ // Use DW_OP_deref to tell the debugger to load the pointer and treat it as
+ // the address of the variable.
+ if (UsePointerValue) {
+ assert(!llvm::is_contained(Expr, llvm::dwarf::DW_OP_deref) &&
+ "Debug info already contains DW_OP_deref.");
+ Expr.push_back(llvm::dwarf::DW_OP_deref);
+ }
+
+ unsigned Line = getLineNumber(BD->getLocation());
+ unsigned Column = getColumnNumber(BD->getLocation());
+ StringRef Name = BD->getName();
+ auto *Scope = cast<llvm::DIScope>(LexicalBlockStack.back());
+ // Create the descriptor for the variable.
+ llvm::DILocalVariable *D = DBuilder.createAutoVariable(
+ Scope, Name, Unit, Line, Ty, CGM.getLangOpts().Optimize,
+ llvm::DINode::FlagZero, Align);
+
+ if (const MemberExpr *ME = dyn_cast<MemberExpr>(BD->getBinding())) {
+ if (const FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
+ const unsigned fieldIndex = FD->getFieldIndex();
+ const clang::CXXRecordDecl *parent =
+ (const CXXRecordDecl *)FD->getParent();
+ const ASTRecordLayout &layout =
+ CGM.getContext().getASTRecordLayout(parent);
+ const uint64_t fieldOffset = layout.getFieldOffset(fieldIndex);
+
+ if (fieldOffset != 0) {
+ Expr.push_back(llvm::dwarf::DW_OP_plus_uconst);
+ Expr.push_back(
+ CGM.getContext().toCharUnitsFromBits(fieldOffset).getQuantity());
+ }
+ }
+ } else if (const ArraySubscriptExpr *ASE =
+ dyn_cast<ArraySubscriptExpr>(BD->getBinding())) {
+ if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(ASE->getIdx())) {
+ const uint64_t value = IL->getValue().getZExtValue();
+ const uint64_t typeSize = CGM.getContext().getTypeSize(BD->getType());
+
+ if (value != 0) {
+ Expr.push_back(llvm::dwarf::DW_OP_plus_uconst);
+ Expr.push_back(CGM.getContext()
+ .toCharUnitsFromBits(value * typeSize)
+ .getQuantity());
+ }
+ }
+ }
+
+ // Insert an llvm.dbg.declare into the current block.
+ DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(Expr),
+ llvm::DILocation::get(CGM.getLLVMContext(), Line,
+ Column, Scope, CurInlinedAt),
+ Builder.GetInsertBlock());
+
+ return D;
+}
+
llvm::DILocalVariable *
CGDebugInfo::EmitDeclareOfAutoVariable(const VarDecl *VD, llvm::Value *Storage,
CGBuilderTy &Builder,
const bool UsePointerValue) {
assert(CGM.getCodeGenOpts().hasReducedDebugInfo());
+
+ if (auto *DD = dyn_cast<DecompositionDecl>(VD))
+ for (auto *B : DD->bindings()) {
+ EmitDeclare(B, Storage, llvm::None, Builder,
+ VD->getType()->isReferenceType());
+ }
+
return EmitDeclare(VD, Storage, llvm::None, Builder, UsePointerValue);
}
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index a76426e585c8e..165ece4224c99 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -583,6 +583,14 @@ class CGDebugInfo {
CGBuilderTy &Builder,
const bool UsePointerValue = false);
+ /// Emit call to llvm.dbg.declare for a binding declaration.
+ /// Returns a pointer to the DILocalVariable associated with the
+ /// llvm.dbg.declare, or nullptr otherwise.
+ llvm::DILocalVariable *EmitDeclare(const BindingDecl *decl, llvm::Value *AI,
+ llvm::Optional<unsigned> ArgNo,
+ CGBuilderTy &Builder,
+ const bool UsePointerValue = false);
+
struct BlockByRefType {
/// The wrapper struct used inside the __block_literal struct.
llvm::DIType *BlockByRefWrapper;
diff --git a/clang/test/CodeGenCXX/debug-info-structured-binding.cpp b/clang/test/CodeGenCXX/debug-info-structured-binding.cpp
new file mode 100644
index 0000000000000..27b918bffa6f2
--- /dev/null
+++ b/clang/test/CodeGenCXX/debug-info-structured-binding.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -emit-llvm -debug-info-kind=standalone -triple %itanium_abi_triple %s -o - | FileCheck %s
+
+// CHECK: call void @llvm.dbg.declare(metadata %struct.A* %{{[0-9]+}}, metadata !{{[0-9]+}}, metadata !DIExpression())
+// CHECK: call void @llvm.dbg.declare(metadata %struct.A* %{{[0-9]+}}, metadata !{{[0-9]+}}, metadata !DIExpression(DW_OP_plus_uconst, {{[0-9]+}}))
+// CHECK: call void @llvm.dbg.declare(metadata %struct.A* %{{[0-9]+}}, metadata !{{[0-9]+}}, metadata !DIExpression())
+// CHECK: call void @llvm.dbg.declare(metadata %struct.A** %{{[0-9]+}}, metadata !{{[0-9]+}}, metadata !DIExpression(DW_OP_deref))
+// CHECK: call void @llvm.dbg.declare(metadata %struct.A** %{{[0-9]+}}, metadata !{{[0-9]+}}, metadata !DIExpression(DW_OP_deref, DW_OP_plus_uconst, {{[0-9]+}}))
+// CHECK: call void @llvm.dbg.declare(metadata %struct.A** %{{[0-9]+}}, metadata !{{[0-9]+}}, metadata !DIExpression())
+struct A {
+ int x;
+ int y;
+};
+
+int f() {
+ A a{10, 20};
+ auto [x1, y1] = a;
+ auto &[x2, y2] = a;
+ return x1 + y1 + x2 + y2;
+}
diff --git a/lldb/test/API/lang/cpp/structured-binding/Makefile b/lldb/test/API/lang/cpp/structured-binding/Makefile
new file mode 100644
index 0000000000000..d5f5fec8441b5
--- /dev/null
+++ b/lldb/test/API/lang/cpp/structured-binding/Makefile
@@ -0,0 +1,4 @@
+CXX_SOURCES := main.cpp
+CXXFLAGS_EXTRAS := -std=c++17
+
+include Makefile.rules
diff --git a/lldb/test/API/lang/cpp/structured-binding/TestStructuredBinding.py b/lldb/test/API/lang/cpp/structured-binding/TestStructuredBinding.py
new file mode 100644
index 0000000000000..694377341a03c
--- /dev/null
+++ b/lldb/test/API/lang/cpp/structured-binding/TestStructuredBinding.py
@@ -0,0 +1,84 @@
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+class TestStructuredBinding(TestBase):
+
+ mydir = TestBase.compute_mydir(__file__)
+
+ @skipIf(compiler="clang", compiler_version=['<', '14.0'])
+ def test(self):
+ self.build()
+ lldbutil.run_to_source_breakpoint(self, "// break here", lldb.SBFileSpec("main.cpp"))
+
+ self.expect_expr("a1", result_type="A",
+ result_children=[ValueCheck(name="x", type="int"),
+ ValueCheck(name="y", type="int")])
+ self.expect_expr("b1", result_type="char", result_value="'a'")
+ self.expect_expr("c1", result_type="char", result_value="'b'")
+ self.expect_expr("d1", result_type="short", result_value="50")
+ self.expect_expr("e1", result_type="int", result_value="60")
+ self.expect_expr("f1", result_type="char", result_value="'c'")
+
+ self.expect_expr("a2", result_type="A",
+ result_children=[ValueCheck(name="x", type="int"),
+ ValueCheck(name="y", type="int")])
+ self.expect_expr("b2", result_type="char", result_value="'a'")
+ self.expect_expr("c2", result_type="char", result_value="'b'")
+ self.expect_expr("d2", result_type="short", result_value="50")
+ self.expect_expr("e2", result_type="int", result_value="60")
+ self.expect_expr("f2", result_type="char", result_value="'c'")
+
+ self.expect_expr("a3", result_type="A",
+ result_children=[ValueCheck(name="x", type="int"),
+ ValueCheck(name="y", type="int")])
+ self.expect_expr("b3", result_type="char", result_value="'a'")
+ self.expect_expr("c3", result_type="char", result_value="'b'")
+ self.expect_expr("d3", result_type="short", result_value="50")
+ self.expect_expr("e3", result_type="int", result_value="60")
+ self.expect_expr("f3", result_type="char", result_value="'c'")
+
+ self.expect_expr("carr_ref1", result_type="char", result_value="'a'")
+ self.expect_expr("carr_ref2", result_type="char", result_value="'b'")
+ self.expect_expr("carr_ref3", result_type="char", result_value="'c'")
+
+ self.expect_expr("sarr_ref1", result_type="short", result_value="11")
+ self.expect_expr("sarr_ref2", result_type="short", result_value="12")
+ self.expect_expr("sarr_ref3", result_type="short", result_value="13")
+
+ self.expect_expr("iarr_ref1", result_type="int", result_value="22")
+ self.expect_expr("iarr_ref2", result_type="int", result_value="33")
+ self.expect_expr("iarr_ref3", result_type="int", result_value="44")
+
+ self.expect_expr("carr_rref1", result_type="char", result_value="'a'")
+ self.expect_expr("carr_rref2", result_type="char", result_value="'b'")
+ self.expect_expr("carr_rref3", result_type="char", result_value="'c'")
+
+ self.expect_expr("sarr_rref1", result_type="short", result_value="11")
+ self.expect_expr("sarr_rref2", result_type="short", result_value="12")
+ self.expect_expr("sarr_rref3", result_type="short", result_value="13")
+
+ self.expect_expr("iarr_rref1", result_type="int", result_value="22")
+ self.expect_expr("iarr_rref2", result_type="int", result_value="33")
+ self.expect_expr("iarr_rref3", result_type="int", result_value="44")
+
+ self.expect_expr("carr_copy1", result_type="char", result_value="'a'")
+ self.expect_expr("carr_copy2", result_type="char", result_value="'b'")
+ self.expect_expr("carr_copy3", result_type="char", result_value="'c'")
+
+ self.expect_expr("sarr_copy1", result_type="short", result_value="11")
+ self.expect_expr("sarr_copy2", result_type="short", result_value="12")
+ self.expect_expr("sarr_copy3", result_type="short", result_value="13")
+
+ self.expect_expr("iarr_copy1", result_type="int", result_value="22")
+ self.expect_expr("iarr_copy2", result_type="int", result_value="33")
+ self.expect_expr("iarr_copy3", result_type="int", result_value="44")
+
+ self.expect_expr("tx1", result_type="float", result_value="4")
+ self.expect_expr("ty1", result_type="char", result_value="'z'")
+ self.expect_expr("tz1", result_type="int", result_value="10")
+
+ self.expect_expr("tx2", result_type="float", result_value="4")
+ self.expect_expr("ty2", result_type="char", result_value="'z'")
+ self.expect_expr("tz2", result_type="int", result_value="10")
diff --git a/lldb/test/API/lang/cpp/structured-binding/main.cpp b/lldb/test/API/lang/cpp/structured-binding/main.cpp
new file mode 100644
index 0000000000000..3fbfb18dbeff0
--- /dev/null
+++ b/lldb/test/API/lang/cpp/structured-binding/main.cpp
@@ -0,0 +1,69 @@
+// Structured binding in C++ can bind identifiers to subobjects of an object.
+//
+// There are three cases we need to test:
+// 1) arrays
+// 2) tuples like objects
+// 3) non-static data members
+//
+// They can also bind by copy, reference or rvalue reference.
+
+#include <tuple>
+
+struct A {
+ int x;
+ int y;
+};
+
+// We want to cover a mix of types and also
diff erent sizes to make sure we
+// hande the offsets correctly.
+struct MixedTypesAndSizesStruct {
+ A a;
+ char b1;
+ char b2;
+ short b3;
+ int b4;
+ char b5;
+};
+
+int main() {
+ MixedTypesAndSizesStruct b{{20, 30}, 'a', 'b', 50, 60, 'c'};
+
+ auto [a1, b1, c1, d1, e1, f1] = b;
+ auto &[a2, b2, c2, d2, e2, f2] = b;
+ auto &&[a3, b3, c3, d3, e3, f3] =
+ MixedTypesAndSizesStruct{{20, 30}, 'a', 'b', 50, 60, 'c'};
+
+ // Array with
diff erent sized types
+ char carr[]{'a', 'b', 'c'};
+ short sarr[]{11, 12, 13};
+ int iarr[]{22, 33, 44};
+
+ auto [carr_copy1, carr_copy2, carr_copy3] = carr;
+ auto [sarr_copy1, sarr_copy2, sarr_copy3] = sarr;
+ auto [iarr_copy1, iarr_copy2, iarr_copy3] = iarr;
+
+ auto &[carr_ref1, carr_ref2, carr_ref3] = carr;
+ auto &[sarr_ref1, sarr_ref2, sarr_ref3] = sarr;
+ auto &[iarr_ref1, iarr_ref2, iarr_ref3] = iarr;
+
+ auto &&[carr_rref1, carr_rref2, carr_rref3] = carr;
+ auto &&[sarr_rref1, sarr_rref2, sarr_rref3] = sarr;
+ auto &&[iarr_rref1, iarr_rref2, iarr_rref3] = iarr;
+
+ float x{4.0};
+ char y{'z'};
+ int z{10};
+
+ std::tuple<float, char, int> tpl(x, y, z);
+ auto [tx1, ty1, tz1] = tpl;
+ auto &[tx2, ty2, tz2] = tpl;
+
+ return a1.x + b1 + c1 + d1 + e1 + f1 + a2.y + b2 + c2 + d2 + e2 + f2 + a3.x +
+ b3 + c3 + d3 + e3 + f3 + carr_copy1 + carr_copy2 + carr_copy3 +
+ sarr_copy1 + sarr_copy2 + sarr_copy3 + iarr_copy1 + iarr_copy2 +
+ iarr_copy3 + carr_ref1 + carr_ref2 + carr_ref3 + sarr_ref1 +
+ sarr_ref2 + sarr_ref3 + iarr_ref1 + iarr_ref2 + iarr_ref3 +
+ carr_rref1 + carr_rref2 + carr_rref3 + sarr_rref1 + sarr_rref2 +
+ sarr_rref3 + iarr_rref1 + iarr_rref2 + iarr_rref3 + tx1 + ty1 + tz1 +
+ tx2 + ty2 + tz2; // break here
+}
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