[llvm] r242338 - Add a "debugger tuning" concept that allows us to fine-tune how we
Paul Robinson
paul_robinson at playstation.sony.com
Wed Jul 15 15:04:54 PDT 2015
Author: probinson
Date: Wed Jul 15 17:04:54 2015
New Revision: 242338
URL: http://llvm.org/viewvc/llvm-project?rev=242338&view=rev
Log:
Add a "debugger tuning" concept that allows us to fine-tune how we
emit debug info, according to the preferences of the different
debuggers used on various targets.
Darwin and FreeBSD default to tuning for LLDB; PS4 defaults to tuning for
the SCE (Sony Computer Entertainment) debugger. All others default to GDB.
Differential Revision: http://reviews.llvm.org/D8506
Added:
llvm/trunk/test/DebugInfo/X86/debugger-tune.ll
Modified:
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
llvm/trunk/test/DebugInfo/X86/tls.ll
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=242338&r1=242337&r2=242338&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Wed Jul 15 17:04:54 2015
@@ -76,6 +76,17 @@ static cl::opt<bool> GenerateARangeSecti
cl::desc("Generate dwarf aranges"),
cl::init(false));
+static cl::opt<DebuggerKind>
+DebuggerTuningOpt("debugger-tune",
+ cl::desc("Tune debug info for a particular debugger"),
+ cl::init(DebuggerKind::Default),
+ cl::values(
+ clEnumValN(DebuggerKind::GDB, "gdb", "gdb"),
+ clEnumValN(DebuggerKind::LLDB, "lldb", "lldb"),
+ clEnumValN(DebuggerKind::SCE, "sce",
+ "SCE targets (e.g. PS4)"),
+ clEnumValEnd));
+
namespace {
enum DefaultOnOff { Default, Enable, Disable };
}
@@ -197,32 +208,44 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Mo
UsedNonDefaultText(false),
SkeletonHolder(A, "skel_string", DIEValueAllocator),
IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()),
- IsPS4(Triple(A->getTargetTriple()).isPS4()),
AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
dwarf::DW_FORM_data4)),
AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
dwarf::DW_FORM_data4)),
AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset,
dwarf::DW_FORM_data4)),
- AccelTypes(TypeAtoms) {
+ AccelTypes(TypeAtoms), DebuggerTuning(DebuggerKind::Default) {
CurFn = nullptr;
CurMI = nullptr;
+ Triple TT(Asm->getTargetTriple());
+
+ // Make sure we know our "debugger tuning." The command-line option takes
+ // precedence; fall back to triple-based defaults.
+ if (DebuggerTuningOpt != DebuggerKind::Default)
+ DebuggerTuning = DebuggerTuningOpt;
+ else if (IsDarwin || TT.isOSFreeBSD())
+ DebuggerTuning = DebuggerKind::LLDB;
+ else if (TT.isPS4CPU())
+ DebuggerTuning = DebuggerKind::SCE;
+ else
+ DebuggerTuning = DebuggerKind::GDB;
- // Turn on accelerator tables for Darwin by default, pubnames by
- // default for non-Darwin/PS4, and handle split dwarf.
+ // Turn on accelerator tables for LLDB by default.
if (DwarfAccelTables == Default)
- HasDwarfAccelTables = IsDarwin;
+ HasDwarfAccelTables = tuneForLLDB();
else
HasDwarfAccelTables = DwarfAccelTables == Enable;
+ // Handle split DWARF. Off by default for now.
if (SplitDwarf == Default)
HasSplitDwarf = false;
else
HasSplitDwarf = SplitDwarf == Enable;
+ // Pubnames/pubtypes on by default for GDB.
if (DwarfPubSections == Default)
- HasDwarfPubSections = !IsDarwin && !IsPS4;
+ HasDwarfPubSections = tuneForGDB();
else
HasDwarfPubSections = DwarfPubSections == Enable;
@@ -230,9 +253,12 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Mo
DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber
: MMI->getModule()->getDwarfVersion();
- // Darwin and PS4 use the standard TLS opcode (defined in DWARF 3).
- // Everybody else uses GNU's.
- UseGNUTLSOpcode = !(IsDarwin || IsPS4) || DwarfVersion < 3;
+ // Work around a GDB bug. GDB doesn't support the standard opcode;
+ // SCE doesn't support GNU's; LLDB prefers the standard opcode, which
+ // is defined as of DWARF 3.
+ // See GDB bug 11616 - DW_OP_form_tls_address is unimplemented
+ // https://sourceware.org/bugzilla/show_bug.cgi?id=11616
+ UseGNUTLSOpcode = tuneForGDB() || DwarfVersion < 3;
Asm->OutStreamer->getContext().setDwarfVersion(DwarfVersion);
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h?rev=242338&r1=242337&r2=242338&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h Wed Jul 15 17:04:54 2015
@@ -203,6 +203,30 @@ struct SymbolCU {
DwarfCompileUnit *CU;
};
+/// Identify a debugger for "tuning" the debug info.
+///
+/// The "debugger tuning" concept allows us to present a more intuitive
+/// interface that unpacks into different sets of defaults for the various
+/// individual feature-flag settings, that suit the preferences of the
+/// various debuggers. However, it's worth remembering that debuggers are
+/// not the only consumers of debug info, and some variations in DWARF might
+/// better be treated as target/platform issues. Fundamentally,
+/// o if the feature is useful (or not) to a particular debugger, regardless
+/// of the target, that's a tuning decision;
+/// o if the feature is useful (or not) on a particular platform, regardless
+/// of the debugger, that's a target decision.
+/// It's not impossible to see both factors in some specific case.
+///
+/// The "tuning" should be used to set defaults for individual feature flags
+/// in DwarfDebug; if a given feature has a more specific command-line option,
+/// that option should take precedence over the tuning.
+enum class DebuggerKind {
+ Default, // No specific tuning requested.
+ GDB, // Tune debug info for gdb.
+ LLDB, // Tune debug info for lldb.
+ SCE // Tune debug info for SCE targets (e.g. PS4).
+};
+
/// Collects and handles dwarf debug information.
class DwarfDebug : public AsmPrinterHandler {
/// Target of Dwarf emission.
@@ -338,7 +362,6 @@ class DwarfDebug : public AsmPrinterHand
/// True iff there are multiple CUs in this module.
bool SingleCU;
bool IsDarwin;
- bool IsPS4;
AddressPool AddrPool;
@@ -349,6 +372,9 @@ class DwarfDebug : public AsmPrinterHand
DenseMap<const Function *, DISubprogram *> FunctionDIs;
+ // Identify a debugger for "tuning" the debug info.
+ DebuggerKind DebuggerTuning;
+
MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() {
@@ -565,6 +591,15 @@ public:
/// standard DW_OP_form_tls_address opcode
bool useGNUTLSOpcode() const { return UseGNUTLSOpcode; }
+ /// \defgroup DebuggerTuning Predicates to tune DWARF for a given debugger.
+ ///
+ /// Returns whether we are "tuning" for a given debugger.
+ /// @{
+ bool tuneForGDB() const { return DebuggerTuning == DebuggerKind::GDB; }
+ bool tuneForLLDB() const { return DebuggerTuning == DebuggerKind::LLDB; }
+ bool tuneForSCE() const { return DebuggerTuning == DebuggerKind::SCE; }
+ /// @}
+
// Experimental DWARF5 features.
/// Returns whether or not to emit tables that dwarf consumers can
Added: llvm/trunk/test/DebugInfo/X86/debugger-tune.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/debugger-tune.ll?rev=242338&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/debugger-tune.ll (added)
+++ llvm/trunk/test/DebugInfo/X86/debugger-tune.ll Wed Jul 15 17:04:54 2015
@@ -0,0 +1,44 @@
+; Verify target-based defaults for "debugger tuning," and the ability to
+; override defaults.
+; We use existence of the debug_pubnames section to distinguish the GDB case,
+; and the apple_names section to distinguish the LLDB case. SCE has neither.
+
+; Verify defaults for various targets.
+; RUN: llc -mtriple=x86_64-scei-ps4 -filetype=obj < %s | llvm-readobj -sections - | FileCheck --check-prefix=SCE %s
+; RUN: llc -mtriple=x86_64-apple-darwin12 -filetype=obj < %s | llvm-readobj -sections - | FileCheck --check-prefix=LLDB %s
+; RUN: llc -mtriple=x86_64-pc-freebsd -filetype=obj < %s | llvm-readobj -sections - | FileCheck --check-prefix=LLDB %s
+; RUN: llc -mtriple=x86_64-pc-linux -filetype=obj < %s | llvm-readobj -sections - | FileCheck --check-prefix=GDB %s
+
+; We can override defaults.
+; RUN: llc -mtriple=x86_64-scei-ps4 -filetype=obj -debugger-tune=gdb < %s | llvm-readobj -sections - | FileCheck --check-prefix=GDB %s
+; RUN: llc -mtriple=x86_64-pc-linux -filetype=obj -debugger-tune=lldb < %s | llvm-readobj -sections - | FileCheck --check-prefix=LLDB %s
+; RUN: llc -mtriple=x86_64-apple-darwin12 -filetype=obj -debugger-tune=sce < %s | llvm-readobj -sections - | FileCheck --check-prefix=SCE %s
+
+
+; GDB-NOT: apple_names
+; GDB: debug_pubnames
+; GDB-NOT: apple_names
+
+; LLDB-NOT: debug_pubnames
+; LLDB: apple_names
+; LLDB-NOT: debug_pubnames
+
+; SCE-NOT: debug_pubnames
+; SCE-NOT: apple_names
+
+
+ at globalvar = global i32 0, align 4
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!6, !7}
+!llvm.ident = !{!8}
+
+!0 = !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.7.0 (trunk 238808)", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, retainedTypes: !2, subprograms: !2, globals: !3, imports: !2)
+!1 = !DIFile(filename: "debugger-tune.cpp", directory: "/home/probinson/projects/scratch")
+!2 = !{}
+!3 = !{!4}
+!4 = !DIGlobalVariable(name: "globalvar", scope: !0, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, variable: i32* @globalvar)
+!5 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!6 = !{i32 2, !"Dwarf Version", i32 4}
+!7 = !{i32 2, !"Debug Info Version", i32 3}
+!8 = !{!"clang version 3.7.0 (trunk 238808)"}
Modified: llvm/trunk/test/DebugInfo/X86/tls.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/tls.ll?rev=242338&r1=242337&r2=242338&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/tls.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/tls.ll Wed Jul 15 17:04:54 2015
@@ -14,7 +14,7 @@
; RUN: | FileCheck --check-prefix=DARWIN --check-prefix=STDOP %s
; RUN: llc %s -o - -filetype=asm -O0 -mtriple=x86_64-unknown-freebsd \
-; RUN: | FileCheck --check-prefix=SINGLE --check-prefix=SINGLE-64 --check-prefix=GNUOP %s
+; RUN: | FileCheck --check-prefix=SINGLE --check-prefix=SINGLE-64 --check-prefix=STDOP %s
; FIXME: add relocation and DWARF expression support to llvm-dwarfdump & use
; that here instead of raw assembly printing
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