[clang] 72b73e2 - Revert "demangle function names in trace files (#87626)"

[via cfe-commits]

Author: Fangrui Song
Date: 2024-08-07T12:23:28-07:00
New Revision: 72b73e23b6c36537db730ebea00f92798108a6e5

URL: https://github.com/llvm/llvm-project/commit/72b73e23b6c36537db730ebea00f92798108a6e5
DIFF: https://github.com/llvm/llvm-project/commit/72b73e23b6c36537db730ebea00f92798108a6e5.diff

LOG: Revert "demangle function names in trace files (#87626)"

This reverts commit 0fa20c55b58deb94090985a5c5ffda4d5ceb3cd1.

Storing raw symbol names is generally preferred in profile files.
Demangling might lose information. Language frontends might use
demangling schemes not supported by LLVMDemangle
(https://github.com/llvm/llvm-project/issues/45901#issuecomment-2008686663).
In addition, calling `demangle` for each function has a significant
performance overhead (#102222).

I believe that even if we decide to provide a producer-side demangling,
it would not be on by default.

Pull Request: https://github.com/llvm/llvm-project/pull/102274

Added: 
    

Modified: 
    clang/test/Driver/ftime-trace-sections.py
    llvm/lib/IR/LegacyPassManager.cpp
    llvm/lib/Passes/CMakeLists.txt
    llvm/lib/Passes/StandardInstrumentations.cpp
    utils/bazel/llvm-project-overlay/llvm/BUILD.bazel

Removed: 
    


################################################################################
diff  --git a/clang/test/Driver/ftime-trace-sections.py b/clang/test/Driver/ftime-trace-sections.py
old mode 100755
new mode 100644
index b332931d29a622..02afa4ac54eb7b
--- a/clang/test/Driver/ftime-trace-sections.py
+++ b/clang/test/Driver/ftime-trace-sections.py
@@ -19,10 +19,7 @@ def is_before(range1, range2):
 
 log_contents = json.loads(sys.stdin.read())
 events = log_contents["traceEvents"]
-
-instants = [event for event in events if event["name"] == "InstantiateFunction"]
 codegens = [event for event in events if event["name"] == "CodeGen Function"]
-opts = [event for event in events if event["name"] == "OptFunction"]
 frontends = [event for event in events if event["name"] == "Frontend"]
 backends = [event for event in events if event["name"] == "Backend"]
 
@@ -51,11 +48,3 @@ def is_before(range1, range2):
     ]
 ):
     sys.exit("Not all Frontend section are before all Backend sections!")
-
-# Check that entries for foo exist and are in a demangled form.
-if not any(e for e in instants if "foo<int>" in e["args"]["detail"]):
-    sys.exit("Missing Instantiate entry for foo!")
-if not any(e for e in codegens if "foo<int>" in e["args"]["detail"]):
-    sys.exit("Missing CodeGen entry for foo!")
-if not any(e for e in opts if "foo<int>" in e["args"]["detail"]):
-    sys.exit("Missing Optimize entry for foo!")

diff  --git a/llvm/lib/IR/LegacyPassManager.cpp b/llvm/lib/IR/LegacyPassManager.cpp
index f2a83b50923e9f..96e2f1d7908ba6 100644
--- a/llvm/lib/IR/LegacyPassManager.cpp
+++ b/llvm/lib/IR/LegacyPassManager.cpp
@@ -12,7 +12,6 @@
 
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/ADT/MapVector.h"
-#include "llvm/Demangle/Demangle.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LLVMContext.h"
@@ -1384,8 +1383,7 @@ bool FPPassManager::runOnFunction(Function &F) {
 
   // Store name outside of loop to avoid redundant calls.
   const StringRef Name = F.getName();
-  llvm::TimeTraceScope FunctionScope(
-      "OptFunction", [&F]() { return demangle(F.getName().str()); });
+  llvm::TimeTraceScope FunctionScope("OptFunction", Name);
 
   for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
     FunctionPass *FP = getContainedPass(Index);

diff  --git a/llvm/lib/Passes/CMakeLists.txt b/llvm/lib/Passes/CMakeLists.txt
index b5224327d79216..6425f4934b2103 100644
--- a/llvm/lib/Passes/CMakeLists.txt
+++ b/llvm/lib/Passes/CMakeLists.txt
@@ -21,7 +21,6 @@ add_llvm_component_library(LLVMPasses
   CodeGen
   Core
   Coroutines
-  Demangle
   HipStdPar
   IPO
   InstCombine

diff  --git a/llvm/lib/Passes/StandardInstrumentations.cpp b/llvm/lib/Passes/StandardInstrumentations.cpp
index 8f2461f40cb004..036484c9c1c0c4 100644
--- a/llvm/lib/Passes/StandardInstrumentations.cpp
+++ b/llvm/lib/Passes/StandardInstrumentations.cpp
@@ -22,7 +22,6 @@
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineVerifier.h"
-#include "llvm/Demangle/Demangle.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Module.h"
@@ -236,12 +235,12 @@ void printIR(raw_ostream &OS, const MachineFunction *MF) {
   MF->print(OS);
 }
 
-std::string getIRName(Any IR, bool demangled = false) {
+std::string getIRName(Any IR) {
   if (unwrapIR<Module>(IR))
     return "[module]";
 
   if (const auto *F = unwrapIR<Function>(IR))
-    return demangled ? demangle(F->getName()) : F->getName().str();
+    return F->getName().str();
 
   if (const auto *C = unwrapIR<LazyCallGraph::SCC>(IR))
     return C->getName();
@@ -251,7 +250,7 @@ std::string getIRName(Any IR, bool demangled = false) {
            L->getHeader()->getParent()->getName().str();
 
   if (const auto *MF = unwrapIR<MachineFunction>(IR))
-    return demangled ? demangle(MF->getName()) : MF->getName().str();
+    return MF->getName().str();
 
   llvm_unreachable("Unknown wrapped IR type");
 }
@@ -1588,7 +1587,7 @@ void TimeProfilingPassesHandler::registerCallbacks(
 }
 
 void TimeProfilingPassesHandler::runBeforePass(StringRef PassID, Any IR) {
-  timeTraceProfilerBegin(PassID, getIRName(IR, true));
+  timeTraceProfilerBegin(PassID, getIRName(IR));
 }
 
 void TimeProfilingPassesHandler::runAfterPass() { timeTraceProfilerEnd(); }

diff  --git a/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel b/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
index c58236a4a3ed2a..1bf6cdbb447a4c 100644
--- a/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
@@ -2654,7 +2654,6 @@ cc_library(
         ":CodeGen",
         ":Core",
         ":Coroutines",
-        ":Demangle",
         ":HipStdPar",
         ":IPO",
         ":IRPrinter",