jmorse created this revision.
jmorse added reviewers: aprantl, vsk, probinson, Orlando, StephenTozer,
TWeaver, djtodoro.
Herald added subscribers: llvm-commits, cfe-commits, hiraditya.
Herald added projects: clang, LLVM.
jmorse added a parent revision: D83047: [LiveDebugValues] 2/4 Add
instruction-referencing LiveDebugValues implementation.
(Context: this thread
http://lists.llvm.org/pipermail/llvm-dev/2020-June/142368.html )
This patch adds the -Xclang option "-fexperimental-debug-variable-locations"
and same LLVM CodeGen option, to pick which variable location tracking solution
to use.
Right now all the switch does is pick which LiveDebugValues implementation to
use. Over time however, my aim is to add fragments of support in aid of this
value-tracking RFC
<http://lists.llvm.org/pipermail/llvm-dev/2020-March/139636.html>, also
controlled by this command line switch. That will slowly move variable
locations to be defined by an instruction calculating a value, and a
DBG_INSTR_REF instruction referring to that value. Thus, this is going to grow
into a "use the new kind of variable locations" switch, rather than just "use
the new LiveDebugValues implementation".
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D83048
Files:
clang/include/clang/Basic/CodeGenOptions.def
clang/include/clang/Driver/CC1Options.td
clang/lib/CodeGen/BackendUtil.cpp
clang/lib/Frontend/CompilerInvocation.cpp
llvm/include/llvm/CodeGen/CommandFlags.h
llvm/include/llvm/Target/TargetOptions.h
llvm/lib/CodeGen/CommandFlags.cpp
llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
Index: llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
===================================================================
--- llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
+++ llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
@@ -3,6 +3,7 @@
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/Passes.h"
+#include "llvm/Target/TargetMachine.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
@@ -49,6 +50,7 @@
}
LDVImpl *TheImpl;
+ TargetPassConfig *TPC;
};
char LiveDebugValues::ID = 0;
@@ -61,15 +63,31 @@
/// Default construct and initialize the pass.
LiveDebugValues::LiveDebugValues() : MachineFunctionPass(ID) {
initializeLiveDebugValuesPass(*PassRegistry::getPassRegistry());
- TheImpl = llvm::makeVarLocBasedLiveDebugValues();
+ TheImpl = nullptr;
}
LiveDebugValues::~LiveDebugValues() {
- delete TheImpl;
+ if (TheImpl)
+ delete TheImpl;
}
bool LiveDebugValues::runOnMachineFunction(MachineFunction &MF) {
- auto *TPC = getAnalysisIfAvailable<TargetPassConfig>();
+ if (!TheImpl) {
+ TPC = getAnalysisIfAvailable<TargetPassConfig>();
+
+ bool InstrRefBased = false;
+ if (TPC) {
+ auto &TM = TPC->getTM<TargetMachine>();
+ InstrRefBased = TM.Options.ValueTrackingVariableLocations;
+ }
+
+ if (InstrRefBased)
+ TheImpl = llvm::makeInstrRefBasedLiveDebugValues();
+ else
+ TheImpl = llvm::makeVarLocBasedLiveDebugValues();
+ }
+
+
return TheImpl->ExtendRanges(MF, TPC);
}
Index: llvm/lib/CodeGen/CommandFlags.cpp
===================================================================
--- llvm/lib/CodeGen/CommandFlags.cpp
+++ llvm/lib/CodeGen/CommandFlags.cpp
@@ -85,6 +85,7 @@
CGOPT(bool, EnableAddrsig)
CGOPT(bool, EmitCallSiteInfo)
CGOPT(bool, EnableDebugEntryValues)
+CGOPT(bool, ValueTrackingVariableLocations)
CGOPT(bool, ForceDwarfFrameSection)
CGOPT(bool, XRayOmitFunctionIndex)
@@ -400,6 +401,12 @@
cl::init(false));
CGBINDOPT(EnableDebugEntryValues);
+ static cl::opt<bool> ValueTrackingVariableLocations(
+ "experimental-debug-variable-locations",
+ cl::desc("Use experimental new value-tracking variable locations"),
+ cl::init(false));
+ CGBINDOPT(ValueTrackingVariableLocations);
+
static cl::opt<bool> ForceDwarfFrameSection(
"force-dwarf-frame-section",
cl::desc("Always emit a debug frame section."), cl::init(false));
@@ -475,6 +482,7 @@
Options.EmitAddrsig = getEnableAddrsig();
Options.EmitCallSiteInfo = getEmitCallSiteInfo();
Options.EnableDebugEntryValues = getEnableDebugEntryValues();
+ Options.ValueTrackingVariableLocations = getValueTrackingVariableLocations();
Options.ForceDwarfFrameSection = getForceDwarfFrameSection();
Options.XRayOmitFunctionIndex = getXRayOmitFunctionIndex();
Index: llvm/include/llvm/Target/TargetOptions.h
===================================================================
--- llvm/include/llvm/Target/TargetOptions.h
+++ llvm/include/llvm/Target/TargetOptions.h
@@ -127,8 +127,8 @@
EmitStackSizeSection(false), EnableMachineOutliner(false),
SupportsDefaultOutlining(false), EmitAddrsig(false),
EmitCallSiteInfo(false), SupportsDebugEntryValues(false),
- EnableDebugEntryValues(false), ForceDwarfFrameSection(false),
- XRayOmitFunctionIndex(false),
+ EnableDebugEntryValues(false), ValueTrackingVariableLocations(false),
+ ForceDwarfFrameSection(false), XRayOmitFunctionIndex(false),
FPDenormalMode(DenormalMode::IEEE, DenormalMode::IEEE) {}
/// PrintMachineCode - This flag is enabled when the -print-machineinstrs
@@ -291,6 +291,11 @@
/// production.
bool ShouldEmitDebugEntryValues() const;
+ // When set to true, use experimental new debug variable location tracking,
+ // which seeks to follow the values of variables rather than their location,
+ // post isel.
+ unsigned ValueTrackingVariableLocations : 1;
+
/// Emit DWARF debug frame section.
unsigned ForceDwarfFrameSection : 1;
Index: llvm/include/llvm/CodeGen/CommandFlags.h
===================================================================
--- llvm/include/llvm/CodeGen/CommandFlags.h
+++ llvm/include/llvm/CodeGen/CommandFlags.h
@@ -116,6 +116,8 @@
bool getEnableDebugEntryValues();
+bool getValueTrackingVariableLocations();
+
bool getForceDwarfFrameSection();
bool getXRayOmitFunctionIndex();
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -791,6 +791,9 @@
llvm::is_contained(DebugEntryValueArchs, T.getArch()))
Opts.EmitCallSiteInfo = true;
+ Opts.ValueTrackingVariableLocations =
+ Args.hasArg(OPT_fexperimental_debug_variable_locations);
+
Opts.DisableO0ImplyOptNone = Args.hasArg(OPT_disable_O0_optnone);
Opts.DisableRedZone = Args.hasArg(OPT_disable_red_zone);
Opts.IndirectTlsSegRefs = Args.hasArg(OPT_mno_tls_direct_seg_refs);
Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -516,6 +516,8 @@
Options.EmitAddrsig = CodeGenOpts.Addrsig;
Options.ForceDwarfFrameSection = CodeGenOpts.ForceDwarfFrameSection;
Options.EmitCallSiteInfo = CodeGenOpts.EmitCallSiteInfo;
+ Options.ValueTrackingVariableLocations =
+ CodeGenOpts.ValueTrackingVariableLocations;
Options.XRayOmitFunctionIndex = CodeGenOpts.XRayOmitFunctionIndex;
Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
Index: clang/include/clang/Driver/CC1Options.td
===================================================================
--- clang/include/clang/Driver/CC1Options.td
+++ clang/include/clang/Driver/CC1Options.td
@@ -389,6 +389,9 @@
HelpText<"Prints debug information for the new pass manager">;
def fno_debug_pass_manager : Flag<["-"], "fno-debug-pass-manager">,
HelpText<"Disables debug printing for the new pass manager">;
+def fexperimental_debug_variable_locations : Flag<["-"],
+ "fexperimental-debug-variable-locations">,
+ HelpText<"Use experimental new value-tracking variable locations">;
// The driver option takes the key as a parameter to the -msign-return-address=
// and -mbranch-protection= options, but CC1 has a separate option so we
// don't have to parse the parameter twice.
Index: clang/include/clang/Basic/CodeGenOptions.def
===================================================================
--- clang/include/clang/Basic/CodeGenOptions.def
+++ clang/include/clang/Basic/CodeGenOptions.def
@@ -325,6 +325,9 @@
/// emitted.
VALUE_CODEGENOPT(DwarfVersion, 3, 0)
+/// Whether to use experimental new variable location tracking.
+CODEGENOPT(ValueTrackingVariableLocations, 1, 0)
+
/// Whether we should emit CodeView debug information. It's possible to emit
/// CodeView and DWARF into the same object.
CODEGENOPT(EmitCodeView, 1, 0)
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