[PATCH] D85799: [DebugInfo] Add -fuse-ctor-homing cc1 flag so we can turn on constructor homing only if limited debug info is already on.

[Amy Huang via Phabricator via cfe-commits]

akhuang updated this revision to Diff 285214.
akhuang added a comment.

Add more extensive check that -fuse-ctor-homing only does something when -debug-info-kind=limited


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85799/new/

https://reviews.llvm.org/D85799

Files:
  clang/include/clang/Driver/Options.td
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGenCXX/debug-info-ctor-homing-flag.cpp


Index: clang/test/CodeGenCXX/debug-info-ctor-homing-flag.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/debug-info-ctor-homing-flag.cpp
@@ -0,0 +1,22 @@
+// RUN: %clang -cc1 -debug-info-kind=constructor -emit-llvm %s -o - \
+// RUN:        | FileCheck %s -check-prefix=CTOR_HOMING
+// RUN: %clang -cc1 -debug-info-kind=limited -fuse-ctor-homing -emit-llvm %s -o - \
+// RUN:        | FileCheck %s -check-prefix=CTOR_HOMING
+// RUN: %clang -cc1 -debug-info-kind=standalone -fuse-ctor-homing -emit-llvm %s -o - \
+// RUN:        | FileCheck %s -check-prefix=FULL_DEBUG
+// RUN: %clang -cc1 -debug-info-kind=line-tables-only -fuse-ctor-homing -emit-llvm %s -o - \
+// RUN:        | FileCheck %s -check-prefix=NO_DEBUG
+// RUN: %clang -cc1 -fuse-ctor-homing -emit-llvm %s -o - \
+// RUN:        | FileCheck %s -check-prefix=NO_DEBUG
+
+
+// This tests that the -fuse-ctor-homing is only used if limited debug info would have
+// been used otherwise.
+
+// CTOR_HOMING: !DICompositeType(tag: DW_TAG_structure_type, name: "A"{{.*}}flags: DIFlagFwdDecl
+// FULL_DEBUG: !DICompositeType(tag: DW_TAG_structure_type, name: "A"{{.*}}DIFlagTypePassByValue
+// NO_DEBUG-NOT: !DICompositeType(tag: DW_TAG_structure_type, name: "A"
+struct A {
+  A();
+} TestA;
+
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -775,6 +775,12 @@
     else
       Opts.setDebugInfo(static_cast<codegenoptions::DebugInfoKind>(Val));
   }
+  // If -fuse-ctor-homing is set and limited debug info is already on, then use
+  // constructor homing.
+  if (Arg *A = Args.getLastArg(OPT_fuse_ctor_homing))
+    if (Opts.getDebugInfo() == codegenoptions::LimitedDebugInfo)
+      Opts.setDebugInfo(codegenoptions::DebugInfoConstructor);
+
   if (Arg *A = Args.getLastArg(OPT_debugger_tuning_EQ)) {
     unsigned Val = llvm::StringSwitch<unsigned>(A->getValue())
                        .Case("gdb", unsigned(llvm::DebuggerKind::GDB))
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -3691,6 +3691,8 @@
   AutoNormalizeEnum;
 def fno_math_builtin : Flag<["-"], "fno-math-builtin">,
   HelpText<"Disable implicit builtin knowledge of math functions">;
+def fuse_ctor_homing: Flag<["-"], "fuse-ctor-homing">,
+    HelpText<"Use constructor homing if we are using limited debug info already">;
 }
 
 def disable_llvm_verifier : Flag<["-"], "disable-llvm-verifier">,


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