[llvm] r338477 - [DebugInfo] Generate fixups as emitting DWARF .debug_line.
Hsiangkai Wang via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 31 19:18:06 PDT 2018
Author: hsiangkai
Date: Tue Jul 31 19:18:06 2018
New Revision: 338477
URL: http://llvm.org/viewvc/llvm-project?rev=338477&view=rev
Log:
[DebugInfo] Generate fixups as emitting DWARF .debug_line.
It is necessary to generate fixups in .debug_line as relaxation is
enabled due to the address delta may be changed after relaxation.
DWARF will record the mappings of lines and addresses in
.debug_line section. It will encode the information using special
opcodes, standard opcodes and extended opcodes in Line Number
Program. I use DW_LNS_fixed_advance_pc to encode fixed length
address delta and DW_LNE_set_address to encode absolute address
to make it possible to generate fixups in .debug_line section.
Differential Revision: https://reviews.llvm.org/D46850
Added:
llvm/trunk/test/DebugInfo/RISCV/
llvm/trunk/test/DebugInfo/RISCV/lit.local.cfg
llvm/trunk/test/DebugInfo/RISCV/relax-debug-line.ll
Modified:
llvm/trunk/include/llvm/MC/MCDwarf.h
llvm/trunk/include/llvm/MC/MCFragment.h
llvm/trunk/lib/MC/MCAssembler.cpp
llvm/trunk/lib/MC/MCDwarf.cpp
Modified: llvm/trunk/include/llvm/MC/MCDwarf.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCDwarf.h?rev=338477&r1=338476&r2=338477&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCDwarf.h (original)
+++ llvm/trunk/include/llvm/MC/MCDwarf.h Tue Jul 31 19:18:06 2018
@@ -362,6 +362,13 @@ public:
static void Encode(MCContext &Context, MCDwarfLineTableParams Params,
int64_t LineDelta, uint64_t AddrDelta, raw_ostream &OS);
+ /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas using
+ /// fixed length operands.
+ static bool FixedEncode(MCContext &Context,
+ MCDwarfLineTableParams Params,
+ int64_t LineDelta, uint64_t AddrDelta,
+ raw_ostream &OS, uint32_t *Offset, uint32_t *Size);
+
/// Utility function to emit the encoding to a streamer.
static void Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
int64_t LineDelta, uint64_t AddrDelta);
Modified: llvm/trunk/include/llvm/MC/MCFragment.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCFragment.h?rev=338477&r1=338476&r2=338477&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCFragment.h (original)
+++ llvm/trunk/include/llvm/MC/MCFragment.h Tue Jul 31 19:18:06 2018
@@ -149,6 +149,7 @@ public:
case MCFragment::FT_Relaxable:
case MCFragment::FT_CompactEncodedInst:
case MCFragment::FT_Data:
+ case MCFragment::FT_Dwarf:
return true;
}
}
@@ -232,7 +233,7 @@ public:
static bool classof(const MCFragment *F) {
MCFragment::FragmentType Kind = F->getKind();
return Kind == MCFragment::FT_Relaxable || Kind == MCFragment::FT_Data ||
- Kind == MCFragment::FT_CVDefRange;
+ Kind == MCFragment::FT_CVDefRange || Kind == MCFragment::FT_Dwarf;;
}
};
@@ -514,7 +515,7 @@ public:
}
};
-class MCDwarfLineAddrFragment : public MCFragment {
+class MCDwarfLineAddrFragment : public MCEncodedFragmentWithFixups<8, 1> {
/// LineDelta - the value of the difference between the two line numbers
/// between two .loc dwarf directives.
int64_t LineDelta;
@@ -523,15 +524,11 @@ class MCDwarfLineAddrFragment : public M
/// make up the address delta between two .loc dwarf directives.
const MCExpr *AddrDelta;
- SmallString<8> Contents;
-
public:
MCDwarfLineAddrFragment(int64_t LineDelta, const MCExpr &AddrDelta,
MCSection *Sec = nullptr)
- : MCFragment(FT_Dwarf, false, Sec), LineDelta(LineDelta),
- AddrDelta(&AddrDelta) {
- Contents.push_back(0);
- }
+ : MCEncodedFragmentWithFixups<8, 1>(FT_Dwarf, false, Sec),
+ LineDelta(LineDelta), AddrDelta(&AddrDelta) {}
/// \name Accessors
/// @{
@@ -540,9 +537,6 @@ public:
const MCExpr &getAddrDelta() const { return *AddrDelta; }
- SmallString<8> &getContents() { return Contents; }
- const SmallString<8> &getContents() const { return Contents; }
-
/// @}
static bool classof(const MCFragment *F) {
Modified: llvm/trunk/lib/MC/MCAssembler.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAssembler.cpp?rev=338477&r1=338476&r2=338477&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCAssembler.cpp (original)
+++ llvm/trunk/lib/MC/MCAssembler.cpp Tue Jul 31 19:18:06 2018
@@ -822,6 +822,9 @@ void MCAssembler::layout(MCAsmLayout &La
} else if (auto *FragWithFixups = dyn_cast<MCCVDefRangeFragment>(&Frag)) {
Fixups = FragWithFixups->getFixups();
Contents = FragWithFixups->getContents();
+ } else if (auto *FragWithFixups = dyn_cast<MCDwarfLineAddrFragment>(&Frag)) {
+ Fixups = FragWithFixups->getFixups();
+ Contents = FragWithFixups->getContents();
} else
llvm_unreachable("Unknown fragment with fixups!");
for (const MCFixup &Fixup : Fixups) {
@@ -951,16 +954,37 @@ bool MCAssembler::relaxDwarfLineAddr(MCA
MCContext &Context = Layout.getAssembler().getContext();
uint64_t OldSize = DF.getContents().size();
int64_t AddrDelta;
- bool Abs = DF.getAddrDelta().evaluateKnownAbsolute(AddrDelta, Layout);
- assert(Abs && "We created a line delta with an invalid expression");
- (void) Abs;
+ bool Abs = DF.getAddrDelta().evaluateAsAbsolute(AddrDelta, Layout);
int64_t LineDelta;
LineDelta = DF.getLineDelta();
- SmallString<8> &Data = DF.getContents();
+ SmallVectorImpl<char> &Data = DF.getContents();
Data.clear();
raw_svector_ostream OSE(Data);
- MCDwarfLineAddr::Encode(Context, getDWARFLinetableParams(), LineDelta,
- AddrDelta, OSE);
+ DF.getFixups().clear();
+
+ if (Abs) {
+ MCDwarfLineAddr::Encode(Context, getDWARFLinetableParams(), LineDelta,
+ AddrDelta, OSE);
+ } else {
+ uint32_t Offset;
+ uint32_t Size;
+ bool SetDelta = MCDwarfLineAddr::FixedEncode(Context,
+ getDWARFLinetableParams(),
+ LineDelta, AddrDelta,
+ OSE, &Offset, &Size);
+ // Add Fixups for address delta or new address.
+ const MCExpr *FixupExpr;
+ if (SetDelta) {
+ FixupExpr = &DF.getAddrDelta();
+ } else {
+ const MCBinaryExpr *ABE = cast<MCBinaryExpr>(&DF.getAddrDelta());
+ FixupExpr = ABE->getLHS();
+ }
+ DF.getFixups().push_back(
+ MCFixup::create(Offset, FixupExpr,
+ MCFixup::getKindForSize(Size, false /*isPCRel*/)));
+ }
+
return OldSize != Data.size();
}
Modified: llvm/trunk/lib/MC/MCDwarf.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCDwarf.cpp?rev=338477&r1=338476&r2=338477&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCDwarf.cpp (original)
+++ llvm/trunk/lib/MC/MCDwarf.cpp Tue Jul 31 19:18:06 2018
@@ -731,6 +731,57 @@ void MCDwarfLineAddr::Encode(MCContext &
}
}
+bool MCDwarfLineAddr::FixedEncode(MCContext &Context,
+ MCDwarfLineTableParams Params,
+ int64_t LineDelta, uint64_t AddrDelta,
+ raw_ostream &OS,
+ uint32_t *Offset, uint32_t *Size) {
+ if (LineDelta != INT64_MAX) {
+ OS << char(dwarf::DW_LNS_advance_line);
+ encodeSLEB128(LineDelta, OS);
+ }
+
+ // Use address delta to adjust address or use absolute address to adjust
+ // address.
+ bool SetDelta;
+ // According to DWARF spec., the DW_LNS_fixed_advance_pc opcode takes a
+ // single uhalf (unencoded) operand. So, the maximum value of AddrDelta
+ // is 65535. We set a conservative upper bound for it for relaxation.
+ if (AddrDelta > 60000) {
+ const MCAsmInfo *asmInfo = Context.getAsmInfo();
+ unsigned AddrSize = asmInfo->getCodePointerSize();
+
+ OS << char(dwarf::DW_LNS_extended_op);
+ encodeULEB128(1 + AddrSize, OS);
+ OS << char(dwarf::DW_LNE_set_address);
+ // Generate fixup for the address.
+ *Offset = OS.tell();
+ *Size = AddrSize;
+ SetDelta = false;
+ std::vector<uint8_t> FillData;
+ FillData.insert(FillData.begin(), AddrSize, 0);
+ OS.write(reinterpret_cast<char *>(FillData.data()), AddrSize);
+ } else {
+ OS << char(dwarf::DW_LNS_fixed_advance_pc);
+ // Generate fixup for 2-bytes address delta.
+ *Offset = OS.tell();
+ *Size = 2;
+ SetDelta = true;
+ OS << char(0);
+ OS << char(0);
+ }
+
+ if (LineDelta == INT64_MAX) {
+ OS << char(dwarf::DW_LNS_extended_op);
+ OS << char(1);
+ OS << char(dwarf::DW_LNE_end_sequence);
+ } else {
+ OS << char(dwarf::DW_LNS_copy);
+ }
+
+ return SetDelta;
+}
+
// Utility function to write a tuple for .debug_abbrev.
static void EmitAbbrev(MCStreamer *MCOS, uint64_t Name, uint64_t Form) {
MCOS->EmitULEB128IntValue(Name);
Added: llvm/trunk/test/DebugInfo/RISCV/lit.local.cfg
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/RISCV/lit.local.cfg?rev=338477&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/RISCV/lit.local.cfg (added)
+++ llvm/trunk/test/DebugInfo/RISCV/lit.local.cfg Tue Jul 31 19:18:06 2018
@@ -0,0 +1,2 @@
+if not 'RISCV' in config.root.targets:
+ config.unsupported = True
Added: llvm/trunk/test/DebugInfo/RISCV/relax-debug-line.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/RISCV/relax-debug-line.ll?rev=338477&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/RISCV/relax-debug-line.ll (added)
+++ llvm/trunk/test/DebugInfo/RISCV/relax-debug-line.ll Tue Jul 31 19:18:06 2018
@@ -0,0 +1,75 @@
+; RUN: llc -filetype=obj -mtriple=riscv32 -mattr=+relax %s -o - \
+; RUN: | llvm-readobj -r | FileCheck -check-prefix=RELAX %s
+;
+; RELAX: .rela.debug_line {
+; RELAX: R_RISCV_ADD16
+; RELAX: R_RISCV_SUB16
+source_filename = "line.c"
+
+; Function Attrs: noinline nounwind optnone
+define i32 @init() !dbg !7 {
+entry:
+ ret i32 0, !dbg !11
+}
+
+; Function Attrs: noinline nounwind optnone
+define i32 @foo(i32 signext %value) !dbg !12 {
+entry:
+ %value.addr = alloca i32, align 4
+ store i32 %value, i32* %value.addr, align 4
+ call void @llvm.dbg.declare(metadata i32* %value.addr, metadata !15, metadata !DIExpression()), !dbg !16
+ %0 = load i32, i32* %value.addr, align 4, !dbg !17
+ ret i32 %0, !dbg !18
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+
+; Function Attrs: noinline nounwind optnone
+define i32 @bar() !dbg !19 {
+entry:
+ %result = alloca i32, align 4
+ %v = alloca i32, align 4
+ call void @llvm.dbg.declare(metadata i32* %result, metadata !20, metadata !DIExpression()), !dbg !21
+ call void @llvm.dbg.declare(metadata i32* %v, metadata !22, metadata !DIExpression()), !dbg !23
+ %call = call i32 @init(), !dbg !24
+ store i32 %call, i32* %v, align 4, !dbg !23
+ %0 = load i32, i32* %v, align 4, !dbg !25
+ %call1 = call i32 @foo(i32 signext %0), !dbg !26
+ store i32 %call1, i32* %result, align 4, !dbg !27
+ %1 = load i32, i32* %result, align 4, !dbg !28
+ ret i32 %1, !dbg !29
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "line.c", directory: "./")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!7 = distinct !DISubprogram(name: "init", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 2, isOptimized: false, unit: !0, retainedNodes: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10}
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = !DILocation(line: 3, column: 3, scope: !7)
+!12 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 6, type: !13, isLocal: false, isDefinition: true, scopeLine: 7, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
+!13 = !DISubroutineType(types: !14)
+!14 = !{!10, !10}
+!15 = !DILocalVariable(name: "value", arg: 1, scope: !12, file: !1, line: 6, type: !10)
+!16 = !DILocation(line: 6, column: 13, scope: !12)
+!17 = !DILocation(line: 8, column: 10, scope: !12)
+!18 = !DILocation(line: 8, column: 3, scope: !12)
+!19 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 11, type: !8, isLocal: false, isDefinition: true, scopeLine: 12, isOptimized: false, unit: !0, retainedNodes: !2)
+!20 = !DILocalVariable(name: "result", scope: !19, file: !1, line: 13, type: !10)
+!21 = !DILocation(line: 13, column: 7, scope: !19)
+!22 = !DILocalVariable(name: "v", scope: !19, file: !1, line: 14, type: !10)
+!23 = !DILocation(line: 14, column: 7, scope: !19)
+!24 = !DILocation(line: 14, column: 11, scope: !19)
+!25 = !DILocation(line: 16, column: 16, scope: !19)
+!26 = !DILocation(line: 16, column: 12, scope: !19)
+!27 = !DILocation(line: 16, column: 10, scope: !19)
+!28 = !DILocation(line: 18, column: 10, scope: !19)
+!29 = !DILocation(line: 18, column: 3, scope: !19)
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