[llvm][DebugInfo] Fix c++20 warnings in LVOptions.h

[DavidSpickett]

Compiling with -DCMAKE_CXX_STANDARD=20 produces 228 warnings from this file due to:

LVOptions.h:515:16: warning: implicit capture of 'this' with a capture default of '=' is deprecated [-Wdeprecated-this-capture]

So I've changed these to explicitly list the captures, including this.

As llvm requires at least c++17, I think we could use [=, *this] instead. However when I did so I got a lot of errors about const. So on balance, explicitly listing the captures seems better than adding some kind of const cast to each one.

These and other warnings can be seen on the c++20 buildbot https://lab.llvm.org/buildbot/#/builders/249.

[llvmbot]

@llvm/pr-subscribers-debuginfo

Author: David Spickett (DavidSpickett)

Changes

Compiling with -DCMAKE_CXX_STANDARD=20 produces 228 warnings from this file due to:

LVOptions.h:515:16: warning: implicit capture of 'this' with a capture default of '=' is deprecated [-Wdeprecated-this-capture]

So I've changed these to explicitly list the captures, including this.

As llvm requires at least c++17, I think we could use [=, *this] instead. However when I did so I got a lot of errors about const. So on balance, explicitly listing the captures seems better than adding some kind of const cast to each one.

These and other warnings can be seen on the c++20 buildbot https://lab.llvm.org/buildbot/#/builders/249.

---

Full diff: https://github.com/llvm/llvm-project/pull/79585.diff

1 Files Affected:

• (modified) llvm/include/llvm/DebugInfo/LogicalView/Core/LVOptions.h (+4-4)

diff --git a/llvm/include/llvm/DebugInfo/LogicalView/Core/LVOptions.h b/llvm/include/llvm/DebugInfo/LogicalView/Core/LVOptions.h
index a0a360c0a434f91..a8bf33f9ad6b290 100644
--- a/llvm/include/llvm/DebugInfo/LogicalView/Core/LVOptions.h
+++ b/llvm/include/llvm/DebugInfo/LogicalView/Core/LVOptions.h
@@ -510,14 +510,14 @@ class LVPatterns final {
   template <typename T, typename U>
   void resolveGenericPatternMatch(T *Element, const U &Requests) {
     assert(Element && "Element must not be nullptr");
-    auto CheckPattern = [=]() -> bool {
+    auto CheckPattern = [this, Element]() -> bool {
       return (Element->isNamed() &&
               (matchGenericPattern(Element->getName()) ||
                matchGenericPattern(Element->getLinkageName()))) ||
              (Element->isTyped() &&
               matchGenericPattern(Element->getTypeName()));
     };
-    auto CheckOffset = [=]() -> bool {
+    auto CheckOffset = [this, Element]() -> bool {
       return matchOffsetPattern(Element->getOffset());
     };
     if ((options().getSelectGenericPattern() && CheckPattern()) ||
@@ -530,12 +530,12 @@ class LVPatterns final {
   template <typename U>
   void resolveGenericPatternMatch(LVLine *Line, const U &Requests) {
     assert(Line && "Line must not be nullptr");
-    auto CheckPattern = [=]() -> bool {
+    auto CheckPattern = [this, Line]() -> bool {
       return matchGenericPattern(Line->lineNumberAsStringStripped()) ||
              matchGenericPattern(Line->getName()) ||
              matchGenericPattern(Line->getPathname());
     };
-    auto CheckOffset = [=]() -> bool {
+    auto CheckOffset = [this, Line]() -> bool {
       return matchOffsetPattern(Line->getAddress());
     };
     if ((options().getSelectGenericPattern() && CheckPattern()) ||

[DavidSpickett]

If the chosen substitute is ok, I can do the same for more of these warnings.

[CarlosAlbertoEnciso]

Thanks for looking at those warnings. The changes look good.

[dwblaikie]

I'd generally suggest if a lambda doesn't escape its scope, especially when they're short/simple like this (you can see the whole lambda and its call on a page) we should use [&] by default to keep things simple.

Also, it's a bit quirky to define lambdas for a single call a few lines later - perhaps this code would be more clear if it were written without lambdas, and with a possible series of if statements?