[llvm] 6a605b9 - [DebugInfo] Move flag for instr-ref to LLVM option, from TargetOptions

[Jeremy Morse via llvm-commits]

Author: Jeremy Morse
Date: 2022-01-12T13:28:01Z
New Revision: 6a605b97a2006bd391f129a606483656b7c6fb28

URL: https://github.com/llvm/llvm-project/commit/6a605b97a2006bd391f129a606483656b7c6fb28
DIFF: https://github.com/llvm/llvm-project/commit/6a605b97a2006bd391f129a606483656b7c6fb28.diff

LOG: [DebugInfo] Move flag for instr-ref to LLVM option, from TargetOptions

This feature was previously controlled by a TargetOptions flag, and I
figured that codegen::InitTargetOptionsFromCodeGenFlags would default it
to "on" for all frontends. Enabling by default was discussed here:

  https://lists.llvm.org/pipermail/llvm-dev/2021-November/153653.html

and originally supposed to happen in 3c045070882f3, but it didn't actually
take effect, as it turns out frontends initialize TargetOptions themselves.
This patch moves the flag from a TargetOptions flag to a global flag to
CodeGen, where it isn't immediately affected by the frontend being used.
Hopefully this will actually cause instr-ref to be on by default on x86_64
now!

This patch is easily reverted, and chances of turbulence are moderately
high. If you need to revert, please consider instead commenting out the
'return true' part of llvm::debuginfoShouldUseDebugInstrRef to turn the
feature off, and dropping me an email.

Differential Revision: https://reviews.llvm.org/D116821

Added: 
    

Modified: 
    llvm/lib/CodeGen/CommandFlags.cpp
    llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
    llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.h
    llvm/lib/CodeGen/MachineFunction.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/CommandFlags.cpp b/llvm/lib/CodeGen/CommandFlags.cpp
index 4543a88e61f05..1d50e1d22b955 100644
--- a/llvm/lib/CodeGen/CommandFlags.cpp
+++ b/llvm/lib/CodeGen/CommandFlags.cpp
@@ -90,7 +90,6 @@ CGOPT(bool, EnableAddrsig)
 CGOPT(bool, EmitCallSiteInfo)
 CGOPT(bool, EnableMachineFunctionSplitter)
 CGOPT(bool, EnableDebugEntryValues)
-CGOPT_EXP(bool, ValueTrackingVariableLocations)
 CGOPT(bool, ForceDwarfFrameSection)
 CGOPT(bool, XRayOmitFunctionIndex)
 CGOPT(bool, DebugStrictDwarf)
@@ -433,12 +432,6 @@ codegen::RegisterCodeGenFlags::RegisterCodeGenFlags() {
       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> EnableMachineFunctionSplitter(
       "split-machine-functions",
       cl::desc("Split out cold basic blocks from machine functions based on "
@@ -539,12 +532,6 @@ codegen::InitTargetOptionsFromCodeGenFlags(const Triple &TheTriple) {
   Options.DebugStrictDwarf = getDebugStrictDwarf();
   Options.LoopAlignment = getAlignLoops();
 
-  if (auto Opt = getExplicitValueTrackingVariableLocations())
-    Options.ValueTrackingVariableLocations = *Opt;
-  else
-    Options.ValueTrackingVariableLocations =
-        getDefaultValueTrackingVariableLocations(TheTriple);
-
   Options.MCOptions = mc::InitMCTargetOptionsFromFlags();
 
   Options.ThreadModel = getThreadModel();
@@ -698,8 +685,3 @@ void codegen::setFunctionAttributes(StringRef CPU, StringRef Features,
     setFunctionAttributes(CPU, Features, F);
 }
 
-bool codegen::getDefaultValueTrackingVariableLocations(const llvm::Triple &T) {
-  if (T.getArch() == llvm::Triple::x86_64)
-    return true;
-  return false;
-}

diff  --git a/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp b/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
index 691977dc34e6e..2913506853aa4 100644
--- a/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
+++ b/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.cpp
@@ -40,6 +40,10 @@ static cl::opt<bool>
                               "normal DBG_VALUE inputs"),
                      cl::init(false));
 
+static cl::opt<cl::boolOrDefault> ValueTrackingVariableLocations(
+    "experimental-debug-variable-locations",
+    cl::desc("Use experimental new value-tracking variable locations"));
+
 // Options to prevent pathological compile-time behavior. If InputBBLimit and
 // InputDbgValueLimit are both exceeded, range extension is disabled.
 static cl::opt<unsigned> InputBBLimit(
@@ -117,3 +121,13 @@ bool LiveDebugValues::runOnMachineFunction(MachineFunction &MF) {
   return TheImpl->ExtendRanges(MF, DomTree, TPC, InputBBLimit,
                                InputDbgValueLimit);
 }
+
+bool llvm::debuginfoShouldUseDebugInstrRef(const Triple &T) {
+  // Enable by default on x86_64, disable if explicitly turned off on cmdline.
+  if (T.getArch() == llvm::Triple::x86_64 &&
+      ValueTrackingVariableLocations != cl::boolOrDefault::BOU_FALSE)
+    return true;
+
+  // Otherwise: enable if explicitly requestedo n command line.
+  return ValueTrackingVariableLocations == cl::boolOrDefault::BOU_TRUE;
+}

diff  --git a/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.h b/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.h
index a5936c8a96f01..8f0b2ec3e1fc5 100644
--- a/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.h
+++ b/llvm/lib/CodeGen/LiveDebugValues/LiveDebugValues.h
@@ -12,6 +12,7 @@
 #include "llvm/CodeGen/MachineDominators.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/TargetPassConfig.h"
+#include "llvm/ADT/Triple.h"
 
 namespace llvm {
 
@@ -35,6 +36,9 @@ class LDVImpl {
 // Factory functions for LiveDebugValues implementations.
 extern LDVImpl *makeVarLocBasedLiveDebugValues();
 extern LDVImpl *makeInstrRefBasedLiveDebugValues();
+
+extern bool debuginfoShouldUseDebugInstrRef(const Triple &T);
+
 } // namespace llvm
 
 #endif // LLVM_LIB_CODEGEN_LIVEDEBUGVALUES_LIVEDEBUGVALUES_H

diff  --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index 81ed3d0e93ff2..fd5ea5cad072c 100644
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -76,6 +76,8 @@
 #include <utility>
 #include <vector>
 
+#include "LiveDebugValues/LiveDebugValues.h"
+
 using namespace llvm;
 
 #define DEBUG_TYPE "codegen"
@@ -1238,7 +1240,7 @@ bool MachineFunction::useDebugInstrRef() const {
   if (F.hasFnAttribute(Attribute::OptimizeNone))
     return false;
 
-  if (getTarget().Options.ValueTrackingVariableLocations)
+  if (llvm::debuginfoShouldUseDebugInstrRef(getTarget().getTargetTriple()))
     return true;
 
   return false;