aprantl created this revision.
aprantl added reviewers: dblaikie, echristo, dexonsmith.
aprantl added subscribers: davide, llvm-commits, cfe-commits.
aprantl set the repository for this revision to rL LLVM.
As indicated in D18612, sample-based profiling and optimization remarks
currently remove DICompileUnits from llvm.dbg.cu to suppress the emission of
debug info from them. This is somewhat of a hack and only borderline legal IR.
This patch uses the recently introduced NoDebug emission kind in DICompileUnit
to achieve the same result without breaking the Verifier. A nice side-effect of
this change is that it is now possible to combine NoDebug and regular compile
units under LTO.
For simplicity I combined the llvm and cfe patches into one review.
Repository:
rL LLVM
http://reviews.llvm.org/D18808
Files:
include/llvm/IR/DIBuilder.h
lib/CodeGen/AsmPrinter/DwarfDebug.cpp
lib/IR/DIBuilder.cpp
test/DebugInfo/X86/mixed-nodebug-cu.ll
tools/clang/lib/CodeGen/CGDebugInfo.cpp
tools/clang/test/Frontend/optimization-remark.c
tools/clang/test/Frontend/profile-sample-use-loc-tracking.c
Index: tools/clang/test/Frontend/profile-sample-use-loc-tracking.c
===================================================================
--- tools/clang/test/Frontend/profile-sample-use-loc-tracking.c
+++ tools/clang/test/Frontend/profile-sample-use-loc-tracking.c
@@ -10,9 +10,10 @@
// CHECK: , !dbg !
// CHECK-NOT: DW_TAG_base_type
-// But llvm.dbg.cu should be missing (to prevent writing debug info to
+// The CU should be marked NoDebug (to prevent writing debug info to
// the final output).
-// CHECK-NOT: !llvm.dbg.cu = !{
+// CHECK: !llvm.dbg.cu = !{![[CU:.*]]}
+// CHECK: ![[CU]] = distinct !DICompileUnit({{.*}}emissionKind: NoDebug
int bar(int j) {
return (j + j - 2) * (j - 2) * j;
Index: tools/clang/test/Frontend/optimization-remark.c
===================================================================
--- tools/clang/test/Frontend/optimization-remark.c
+++ tools/clang/test/Frontend/optimization-remark.c
@@ -27,9 +27,10 @@
// CHECK: , !dbg !
// CHECK-NOT: DW_TAG_base_type
-// But llvm.dbg.cu should be missing (to prevent writing debug info to
+// The CU should be marked NoDebug (to prevent writing debug info to
// the final output).
-// CHECK-NOT: !llvm.dbg.cu = !{
+// CHECK: !llvm.dbg.cu = !{![[CU:.*]]}
+// CHECK: ![[CU]] = distinct !DICompileUnit({{.*}}emissionKind: NoDebug
int foo(int x, int y) __attribute__((always_inline));
int foo(int x, int y) { return x + y; }
Index: tools/clang/lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- tools/clang/lib/CodeGen/CGDebugInfo.cpp
+++ tools/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -396,16 +396,27 @@
if (LO.ObjC1)
RuntimeVers = LO.ObjCRuntime.isNonFragile() ? 2 : 1;
+ llvm::DICompileUnit::DebugEmissionKind EmissionKind;
+ switch (DebugKind) {
+ case codegenoptions::NoDebugInfo:
+ case codegenoptions::LocTrackingOnly:
+ EmissionKind = llvm::DICompileUnit::NoDebug;
+ break;
+ case codegenoptions::DebugLineTablesOnly:
+ EmissionKind = llvm::DICompileUnit::LineTablesOnly;
+ break;
+ case codegenoptions::LimitedDebugInfo:
+ case codegenoptions::FullDebugInfo:
+ EmissionKind = llvm::DICompileUnit::FullDebug;
+ break;
+ }
+
// Create new compile unit.
// FIXME - Eliminate TheCU.
TheCU = DBuilder.createCompileUnit(
LangTag, remapDIPath(MainFileName), remapDIPath(getCurrentDirname()),
Producer, LO.Optimize, CGM.getCodeGenOpts().DwarfDebugFlags, RuntimeVers,
- CGM.getCodeGenOpts().SplitDwarfFile,
- DebugKind <= codegenoptions::DebugLineTablesOnly
- ? llvm::DICompileUnit::LineTablesOnly
- : llvm::DICompileUnit::FullDebug,
- 0 /* DWOid */, DebugKind != codegenoptions::LocTrackingOnly);
+ CGM.getCodeGenOpts().SplitDwarfFile, EmissionKind, 0 /* DWOid */);
}
llvm::DIType *CGDebugInfo::CreateType(const BuiltinType *BT) {
Index: test/DebugInfo/X86/mixed-nodebug-cu.ll
===================================================================
--- /dev/null
+++ test/DebugInfo/X86/mixed-nodebug-cu.ll
@@ -0,0 +1,50 @@
+; RUN: llc %s -o %t -filetype=obj
+; RUN: llvm-dwarfdump -debug-dump=info %t | FileCheck %s
+; CHECK: DW_TAG_compile_unit
+; CHECK: DW_TAG_subprogram
+; CHECK: DW_AT_name{{.*}}"f"
+; CHECK-NOT: DW_TAG_compile_unit
+;
+; created from
+; void f() {} // compile with -g
+; void g() {} // compile with -Rpass=inline
+; and llvm-linking the result.
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+; Function Attrs: nounwind ssp uwtable
+define void @f() #0 !dbg !4 {
+entry:
+ ret void, !dbg !15
+}
+
+; Function Attrs: nounwind ssp uwtable
+define void @g() #0 !dbg !9 {
+entry:
+ ret void, !dbg !16
+}
+
+attributes #0 = { nounwind ssp uwtable }
+
+!llvm.dbg.cu = !{!0, !7}
+!llvm.ident = !{!11, !11}
+!llvm.module.flags = !{!12, !13, !14}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 (trunk 265328) (llvm/trunk 265330)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, subprograms: !3)
+!1 = !DIFile(filename: "test.c", directory: "/Volumes/Data/llvm")
+!2 = !{}
+!3 = !{!4}
+!4 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, variables: !2)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null}
+!7 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 (trunk 265328) (llvm/trunk 265330)", isOptimized: false, runtimeVersion: 0, emissionKind: NoDebug, enums: !2, subprograms: !8)
+!8 = !{!9}
+!9 = distinct !DISubprogram(name: "g", scope: !1, file: !1, line: 1, type: !10, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, variables: !2)
+!10 = !DISubroutineType(types: !2)
+!11 = !{!"clang version 3.9.0 (trunk 265328) (llvm/trunk 265330)"}
+!12 = !{i32 2, !"Dwarf Version", i32 2}
+!13 = !{i32 2, !"Debug Info Version", i32 3}
+!14 = !{i32 1, !"PIC Level", i32 2}
+!15 = !DILocation(line: 1, column: 12, scope: !4)
+!16 = !DILocation(line: 1, column: 12, scope: !9)
Index: lib/IR/DIBuilder.cpp
===================================================================
--- lib/IR/DIBuilder.cpp
+++ lib/IR/DIBuilder.cpp
@@ -137,7 +137,7 @@
DICompileUnit *DIBuilder::createCompileUnit(
unsigned Lang, StringRef Filename, StringRef Directory, StringRef Producer,
bool isOptimized, StringRef Flags, unsigned RunTimeVer, StringRef SplitName,
- DICompileUnit::DebugEmissionKind Kind, uint64_t DWOId, bool EmitDebugInfo) {
+ DICompileUnit::DebugEmissionKind Kind, uint64_t DWOId) {
assert(((Lang <= dwarf::DW_LANG_Fortran08 && Lang >= dwarf::DW_LANG_C89) ||
(Lang <= dwarf::DW_LANG_hi_user && Lang >= dwarf::DW_LANG_lo_user)) &&
@@ -152,15 +152,8 @@
nullptr, nullptr, nullptr, nullptr, nullptr, DWOId);
// Create a named metadata so that it is easier to find cu in a module.
- // Note that we only generate this when the caller wants to actually
- // emit debug information. When we are only interested in tracking
- // source line locations throughout the backend, we prevent codegen from
- // emitting debug info in the final output by not generating llvm.dbg.cu.
- if (EmitDebugInfo) {
- NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu");
- NMD->addOperand(CUNode);
- }
-
+ NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu");
+ NMD->addOperand(CUNode);
trackIfUnresolved(CUNode);
return CUNode;
}
Index: lib/CodeGen/AsmPrinter/DwarfDebug.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -473,8 +473,13 @@
SingleCU = CU_Nodes->getNumOperands() == 1;
+ unsigned DebugCUs = 0;
for (MDNode *N : CU_Nodes->operands()) {
auto *CUNode = cast<DICompileUnit>(N);
+ if (CUNode->getEmissionKind() == DICompileUnit::NoDebug)
+ continue;
+
+ DebugCUs++;
DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
for (auto *IE : CUNode->getImportedEntities())
CU.addImportedEntity(IE);
@@ -502,7 +507,7 @@
}
// Tell MMI that we have debug info.
- MMI->setDebugInfoAvailability(true);
+ MMI->setDebugInfoAvailability(DebugCUs > 0);
}
void DwarfDebug::finishVariableDefinitions() {
@@ -538,6 +543,9 @@
if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
for (MDNode *N : CU_Nodes->operands()) {
auto *TheCU = cast<DICompileUnit>(N);
+ if (TheCU->getEmissionKind() == DICompileUnit::NoDebug)
+ continue;
+
// Construct subprogram DIE and add variables DIEs.
DwarfCompileUnit *SPCU =
static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
@@ -1090,7 +1098,10 @@
// includes the directory of the cpp file being built, even when the file name
// is absolute (such as an <> lookup header)))
DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
- assert(TheCU && "Unable to find compile unit!");
+ if (!TheCU)
+ // Once DISubprogram points to the owning CU, we can assert that the CU has
+ // a NoDebug EmissionKind here.
+ return;
if (Asm->OutStreamer->hasRawTextSupport())
// Use a single line table if we are generating assembly.
Asm->OutStreamer->getContext().setDwarfCompileUnitID(0);
@@ -1113,7 +1124,8 @@
"endFunction should be called with the same function as beginFunction");
if (!MMI->hasDebugInfo() || LScopes.empty() ||
- !MF->getFunction()->getSubprogram()) {
+ !MF->getFunction()->getSubprogram() ||
+ !SPMap.lookup(MF->getFunction()->getSubprogram())) {
// If we don't have a lexical scope for this function then there will
// be a hole in the range information. Keep note of this by setting the
// previously used section to nullptr.
Index: include/llvm/IR/DIBuilder.h
===================================================================
--- include/llvm/IR/DIBuilder.h
+++ include/llvm/IR/DIBuilder.h
@@ -92,23 +92,13 @@
/// out into.
/// \param Kind The kind of debug information to generate.
/// \param DWOId The DWOId if this is a split skeleton compile unit.
- /// \param EmitDebugInfo A boolean flag which indicates whether
- /// debug information should be written to
- /// the final output or not. When this is
- /// false, debug information annotations will
- /// be present in the IL but they are not
- /// written to the final assembly or object
- /// file. This supports tracking source
- /// location information in the back end
- /// without actually changing the output
- /// (e.g., when using optimization remarks).
DICompileUnit *
createCompileUnit(unsigned Lang, StringRef File, StringRef Dir,
StringRef Producer, bool isOptimized, StringRef Flags,
unsigned RV, StringRef SplitName = StringRef(),
DICompileUnit::DebugEmissionKind Kind =
DICompileUnit::DebugEmissionKind::FullDebug,
- uint64_t DWOId = 0, bool EmitDebugInfo = true);
+ uint64_t DWOId = 0);
/// Create a file descriptor to hold debugging information
/// for a file.
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