[clang] 3e2ad26 - [DebugInfo] Add -fno-ctor-homing for as counterpart to -fuse-ctor-homing

[Amy Huang via cfe-commits]

Author: Amy Huang
Date: 2021-07-22T14:52:36-07:00
New Revision: 3e2ad26b08a23e786e64e8e47547d25a1b5a7f28

URL: https://github.com/llvm/llvm-project/commit/3e2ad26b08a23e786e64e8e47547d25a1b5a7f28
DIFF: https://github.com/llvm/llvm-project/commit/3e2ad26b08a23e786e64e8e47547d25a1b5a7f28.diff

LOG: [DebugInfo] Add -fno-ctor-homing for as counterpart to -fuse-ctor-homing

Add an opt out flag for constructor homing.

Differential Revision: https://reviews.llvm.org/D106582

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index f7f76ed3f3e20..20be01a5f40ac 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -2563,7 +2563,8 @@ below. If multiple flags are present, the last one is used.
    non-trivial, non-aggregate C++ class in the modules that contain a
    definition of one of its constructors. This relies on the additional
    assumption that all classes that are not trivially constructible have a
-   non-trivial constructor that is used somewhere.
+   non-trivial constructor that is used somewhere. The negation,
+   -fno-use-ctor-homing, ensures that constructor homing is not used.
 
    This flag is not enabled by default, and needs to be used with -cc1 or
    -Xclang.

diff  --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 79955f4fa4f08..1815cd4621e87 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -4836,6 +4836,8 @@ def mrelocation_model : Separate<["-"], "mrelocation-model">,
 def fno_math_builtin : Flag<["-"], "fno-math-builtin">,
   HelpText<"Disable implicit builtin knowledge of math functions">,
   MarshallingInfoFlag<LangOpts<"NoMathBuiltin">>;
+def fno_use_ctor_homing: Flag<["-"], "fno-use-ctor-homing">,
+    HelpText<"Don't use constructor homing for debug info">;
 def fuse_ctor_homing: Flag<["-"], "fuse-ctor-homing">,
     HelpText<"Use constructor homing if we are using limited debug info already">;
 }

diff  --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 2c696b5394538..a8f25fa7c11c4 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1369,9 +1369,6 @@ void CompilerInvocation::GenerateCodeGenArgs(
   if (DebugInfoVal)
     GenerateArg(Args, OPT_debug_info_kind_EQ, *DebugInfoVal, SA);
 
-  if (Opts.DebugInfo == codegenoptions::DebugInfoConstructor)
-    GenerateArg(Args, OPT_fuse_ctor_homing, SA);
-
   for (const auto &Prefix : Opts.DebugPrefixMap)
     GenerateArg(Args, OPT_fdebug_prefix_map_EQ,
                 Prefix.first + "=" + Prefix.second, SA);
@@ -1627,10 +1624,16 @@ bool CompilerInvocation::ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args,
   }
 
   // If -fuse-ctor-homing is set and limited debug info is already on, then use
-  // constructor homing.
-  if (Args.getLastArg(OPT_fuse_ctor_homing))
-    if (Opts.getDebugInfo() == codegenoptions::LimitedDebugInfo)
+  // constructor homing, and vice versa for -fno-use-ctor-homing.
+  if (const Arg *A =
+          Args.getLastArg(OPT_fuse_ctor_homing, OPT_fno_use_ctor_homing)) {
+    if (A->getOption().matches(OPT_fuse_ctor_homing) &&
+        Opts.getDebugInfo() == codegenoptions::LimitedDebugInfo)
       Opts.setDebugInfo(codegenoptions::DebugInfoConstructor);
+    if (A->getOption().matches(OPT_fno_use_ctor_homing) &&
+        Opts.getDebugInfo() == codegenoptions::DebugInfoConstructor)
+      Opts.setDebugInfo(codegenoptions::LimitedDebugInfo);
+  }
 
   for (const auto &Arg : Args.getAllArgValues(OPT_fdebug_prefix_map_EQ)) {
     auto Split = StringRef(Arg).split('=');

diff  --git a/clang/test/CodeGenCXX/debug-info-ctor-homing-flag.cpp b/clang/test/CodeGenCXX/debug-info-ctor-homing-flag.cpp
index 5443fa9ade237..e0832f48c5e21 100644
--- a/clang/test/CodeGenCXX/debug-info-ctor-homing-flag.cpp
+++ b/clang/test/CodeGenCXX/debug-info-ctor-homing-flag.cpp
@@ -8,6 +8,9 @@
 // RUN:        | FileCheck %s -check-prefix=NO_DEBUG
 // RUN: %clang -cc1 -fuse-ctor-homing -emit-llvm %s -o - \
 // RUN:        | FileCheck %s -check-prefix=NO_DEBUG
+//
+// RUN: %clang -cc1 -debug-info-kind=constructor -fno-use-ctor-homing \
+// RUN:        -emit-llvm %s -o - | FileCheck %s -check-prefix=FULL_DEBUG
 
 // This tests that the -fuse-ctor-homing is only used if limited debug info would have
 // been used otherwise.