3946c5061d
This patch adds a class that uses SSA construction, with debug values as definitions, to determine whether and which debug values for a particular variable are live at each point in an IR function. This will be used by the IR reader of llvm-debuginfo-analyzer to compute variable ranges and coverage, although it may be applicable to other debug info IR analyses.
220 lines
7.7 KiB
C++
220 lines
7.7 KiB
C++
//===- DebugSSAUpdater.cpp - Unit tests for debug variable tracking -------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Utils/DebugSSAUpdater.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/AsmParser/Parser.h"
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#include "llvm/IR/BasicBlock.h"
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#include "llvm/IR/DebugInfoMetadata.h"
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#include "llvm/IR/DebugProgramInstruction.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/GlobalValue.h"
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#include "llvm/IR/Module.h"
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#include "llvm/Support/SourceMgr.h"
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#include "gtest/gtest.h"
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using namespace llvm;
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static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
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SMDiagnostic Err;
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std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
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if (!Mod)
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Err.print("DebugSSAUpdaterTests", errs());
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return Mod;
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}
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namespace {
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// Verify that two conflicting live-in values result in no live-in range for a
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// block.
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TEST(DebugSSAUpdater, EmptyPHIRange) {
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LLVMContext C;
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std::unique_ptr<Module> M =
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parseIR(C,
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R"(define i32 @foo(i32 %a, i1 %b) !dbg !7 {
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entry:
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#dbg_value(i32 %a, !6, !DIExpression(), !10)
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br i1 %b, label %if.then, label %if.else, !dbg !11
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if.then:
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%c = add i32 %a, 10, !dbg !12
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#dbg_value(i32 %c, !6, !DIExpression(), !13)
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br label %exit, !dbg !14
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if.else:
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%d = mul i32 %a, 3, !dbg !15
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#dbg_value(i32 %d, !6, !DIExpression(), !16)
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br label %exit, !dbg !17
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exit:
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%res = phi i32 [ %c, %if.then ], [ %d, %if.else ], !dbg !18
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ret i32 %res, !dbg !19
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}
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!4}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_17, file: !1, producer: "clang version 20.0.0")
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!1 = !DIFile(filename: "test.cpp", directory: ".")
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!2 = !{}
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!3 = !{i32 7, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{!"clang version 20.0.0"}
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!6 = !DILocalVariable(name: "a", scope: !7, file: !1, line: 11, type: !8)
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!7 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 10, type: !9, scopeLine: 10, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
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!8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!9 = !DISubroutineType(types: !2)
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!10 = !DILocation(line: 10, scope: !7)
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!11 = !DILocation(line: 11, scope: !7)
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!12 = !DILocation(line: 12, scope: !7)
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!13 = !DILocation(line: 13, scope: !7)
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!14 = !DILocation(line: 14, scope: !7)
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!15 = !DILocation(line: 15, scope: !7)
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!16 = !DILocation(line: 16, scope: !7)
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!17 = !DILocation(line: 17, scope: !7)
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!18 = !DILocation(line: 18, scope: !7)
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!19 = !DILocation(line: 19, scope: !7)
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)");
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Function *Foo = &*M->begin();
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DebugVariableAggregate VarA(cast<DbgVariableRecord>(
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Foo->begin()->begin()->getDbgRecordRange().begin()));
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DbgValueRangeTable DbgValueRanges;
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DbgValueRanges.addVariable(Foo, VarA);
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BasicBlock *ExitBlock = &Foo->back();
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// We should have 5 ranges: 1 in the entry block, and 2 in each `if` block,
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// while there should be no range for the exit block.
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EXPECT_EQ(DbgValueRanges.getVariableRanges(VarA).size(), 5u);
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EXPECT_TRUE(none_of(DbgValueRanges.getVariableRanges(VarA),
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[&](DbgRangeEntry VarRange) {
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return VarRange.Start->getParent() == ExitBlock;
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}));
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}
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// Verify that we correctly set live-in variable values through loops.
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TEST(DebugSSAUpdater, LoopPHI) {
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LLVMContext C;
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std::unique_ptr<Module> M =
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parseIR(C,
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R"(define i32 @foo(i32 %a, i32 %max) !dbg !7 {
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entry:
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#dbg_value(i32 %a, !6, !DIExpression(), !10)
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%cond.entry = icmp slt i32 %a, %max, !dbg !11
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br i1 %cond.entry, label %loop, label %exit, !dbg !12
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loop:
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%loop.a = phi i32 [ %a, %entry ], [ %inc, %loop ]
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%inc = add i32 %loop.a, 1, !dbg !13
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%cond.loop = icmp slt i32 %inc, %max, !dbg !14
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br i1 %cond.loop, label %loop, label %exit, !dbg !15
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exit:
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%res = phi i32 [ %a, %entry ], [ %loop.a, %loop ]
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ret i32 %res, !dbg !16
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}
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!4}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_17, file: !1, producer: "clang version 20.0.0")
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!1 = !DIFile(filename: "test.cpp", directory: ".")
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!2 = !{}
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!3 = !{i32 7, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{!"clang version 20.0.0"}
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!6 = !DILocalVariable(name: "a", scope: !7, file: !1, line: 11, type: !8)
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!7 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 10, type: !9, scopeLine: 10, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
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!8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!9 = !DISubroutineType(types: !2)
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!10 = !DILocation(line: 10, scope: !7)
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!11 = !DILocation(line: 11, scope: !7)
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!12 = !DILocation(line: 12, scope: !7)
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!13 = !DILocation(line: 13, scope: !7)
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!14 = !DILocation(line: 14, scope: !7)
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!15 = !DILocation(line: 15, scope: !7)
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!16 = !DILocation(line: 16, scope: !7)
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)");
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Function *Foo = &*M->begin();
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DebugVariableAggregate VarA(cast<DbgVariableRecord>(
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Foo->begin()->begin()->getDbgRecordRange().begin()));
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DbgValueRangeTable DbgValueRanges;
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DbgValueRanges.addVariable(Foo, VarA);
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// We should have 3 ranges: 1 in the entry block, and 1 live-in entry for each
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// of the loops.
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EXPECT_EQ(DbgValueRanges.getVariableRanges(VarA).size(), 3u);
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EXPECT_TRUE(
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all_of(DbgValueRanges.getVariableRanges(VarA),
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[&](DbgRangeEntry VarRange) { return !VarRange.Value.IsUndef; }));
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}
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// Verify that when a variable has only undef debug values, it has no live
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// ranges.
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TEST(DebugSSAUpdater, AllUndefVar) {
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LLVMContext C;
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std::unique_ptr<Module> M =
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parseIR(C,
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R"(define i32 @foo(i32 %a, i1 %b) !dbg !7 {
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entry:
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#dbg_value(i32 poison, !6, !DIExpression(), !10)
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br i1 %b, label %if.then, label %if.else, !dbg !11
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if.then:
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%c = add i32 %a, 10, !dbg !12
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#dbg_value(i32 poison, !6, !DIExpression(), !13)
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br label %exit, !dbg !14
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if.else:
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%d = mul i32 %a, 3, !dbg !15
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#dbg_value(i32 poison, !6, !DIExpression(), !16)
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br label %exit, !dbg !17
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exit:
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%res = phi i32 [ %c, %if.then ], [ %d, %if.else ], !dbg !18
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ret i32 %res, !dbg !19
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}
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!4}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_17, file: !1, producer: "clang version 20.0.0")
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!1 = !DIFile(filename: "test.cpp", directory: ".")
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!2 = !{}
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!3 = !{i32 7, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{!"clang version 20.0.0"}
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!6 = !DILocalVariable(name: "a", scope: !7, file: !1, line: 11, type: !8)
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!7 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 10, type: !9, scopeLine: 10, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
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!8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!9 = !DISubroutineType(types: !2)
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!10 = !DILocation(line: 10, scope: !7)
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!11 = !DILocation(line: 11, scope: !7)
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!12 = !DILocation(line: 12, scope: !7)
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!13 = !DILocation(line: 13, scope: !7)
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!14 = !DILocation(line: 14, scope: !7)
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!15 = !DILocation(line: 15, scope: !7)
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!16 = !DILocation(line: 16, scope: !7)
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!17 = !DILocation(line: 17, scope: !7)
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!18 = !DILocation(line: 18, scope: !7)
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!19 = !DILocation(line: 19, scope: !7)
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)");
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Function *Foo = &*M->begin();
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DebugVariableAggregate VarA(cast<DbgVariableRecord>(
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Foo->begin()->begin()->getDbgRecordRange().begin()));
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DbgValueRangeTable DbgValueRanges;
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DbgValueRanges.addVariable(Foo, VarA);
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// There should be no variable ranges emitted for a variable that has only
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// undef dbg_values.
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EXPECT_EQ(DbgValueRanges.getVariableRanges(VarA).size(), 0u);
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}
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} // namespace
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