aprantl created this revision.
aprantl added reviewers: dblaikie, echristo.
aprantl added a subscriber: cfe-commits.
aprantl set the repository for this revision to rL LLVM.
This patch adds a -gmodules option to the driver and a -dwarf-ext-refs to cc1
to enable the use of external type references in the debug info (a.k.a. module
debugging).
The driver expands -gmodules to "-g -fmodule-format=obj -dwarf-ext-refs" and
passes that to cc1.
Most options that start with -g (e.g., -gdwarf-2) also turn on -g, and module
requires object-container-wrapped modules, "-dwarf-ext-refs" been the actual
low-level option for turning on external type references.
Rationale for the choice of names (and this is really all there is to review in
this patch):
"-gmodules": is meant to pair nicely with "-fmodules"
"-dwarf-ext-refs": Fits into the naming scheme of similar options like
"-dwarf-column-info" and "-dwarf-debug-flags". Spelling out the option
"-dwarf-external-type-references" seemed to be overkill.
All this does at the moment is set a flag codegenopts. Having this flag in
place is a prerequisite for emitting debug info into modules: The debug info
for a module needs to use external type references for types defined in (other)
modules or we would violate the minimal deserialization requirements (cf.
test/PCH/check-deserializations.cpp).
Repository:
rL LLVM
http://reviews.llvm.org/D11958
Files:
docs/CommandGuide/clang.rst
include/clang/Driver/CC1Options.td
include/clang/Driver/Options.td
include/clang/Frontend/CodeGenOptions.def
lib/CodeGen/CGDebugInfo.cpp
lib/CodeGen/CGDebugInfo.h
lib/CodeGen/ObjectFilePCHContainerOperations.cpp
lib/Driver/Tools.cpp
lib/Frontend/CompilerInvocation.cpp
test/Driver/debug-options.c
Index: test/Driver/debug-options.c
===================================================================
--- test/Driver/debug-options.c
+++ test/Driver/debug-options.c
@@ -77,6 +77,9 @@
//
// RUN: %clang -### -g %s 2>&1 | FileCheck -check-prefix=CI %s
//
+// RUN: %clang -### -gmodules %s 2>&1 \
+// RUN: | FileCheck -check-prefix=GEXTREFS %s
+//
// G: "-cc1"
// G: "-g"
//
@@ -126,3 +129,5 @@
// CI: "-dwarf-column-info"
//
// NOCI-NOT: "-dwarf-column-info"
+//
+// GEXTREFS: "-g" "-dwarf-ext-refs" "-fmodule-format=obj"
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -424,6 +424,7 @@
Opts.DwarfVersion = 3;
else if (Args.hasArg(OPT_gdwarf_4))
Opts.DwarfVersion = 4;
+ Opts.DebugTypeExtRefs = Args.hasArg(OPT_dwarf_ext_refs);
if (const Arg *A =
Args.getLastArg(OPT_emit_llvm_uselists, OPT_no_emit_llvm_uselists))
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -3702,6 +3702,12 @@
CmdArgs.push_back("-dwarf-column-info");
// FIXME: Move backend command line options to the module.
+ if (Args.hasArg(options::OPT_gmodules)) {
+ CmdArgs.push_back("-g");
+ CmdArgs.push_back("-dwarf-ext-refs");
+ CmdArgs.push_back("-fmodule-format=obj");
+ }
+
// -gsplit-dwarf should turn on -g and enable the backend dwarf
// splitting and extraction.
// FIXME: Currently only works on Linux.
Index: lib/CodeGen/ObjectFilePCHContainerOperations.cpp
===================================================================
--- lib/CodeGen/ObjectFilePCHContainerOperations.cpp
+++ lib/CodeGen/ObjectFilePCHContainerOperations.cpp
@@ -64,6 +64,7 @@
// ThreadModel, but the backend expects them to be nonempty.
CodeGenOpts.CodeModel = "default";
CodeGenOpts.ThreadModel = "single";
+ CodeGenOpts.DebugTypeExtRefs = true;
CodeGenOpts.setDebugInfo(CodeGenOptions::FullDebugInfo);
CodeGenOpts.SplitDwarfFile = OutputFileName;
}
Index: lib/CodeGen/CGDebugInfo.h
===================================================================
--- lib/CodeGen/CGDebugInfo.h
+++ lib/CodeGen/CGDebugInfo.h
@@ -52,6 +52,7 @@
friend class SaveAndRestoreLocation;
CodeGenModule &CGM;
const CodeGenOptions::DebugInfoKind DebugKind;
+ bool DebugTypeExtRefs;
llvm::DIBuilder DBuilder;
llvm::DICompileUnit *TheCU = nullptr;
SourceLocation CurLoc;
Index: lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- lib/CodeGen/CGDebugInfo.cpp
+++ lib/CodeGen/CGDebugInfo.cpp
@@ -45,6 +45,7 @@
CGDebugInfo::CGDebugInfo(CodeGenModule &CGM)
: CGM(CGM), DebugKind(CGM.getCodeGenOpts().getDebugInfo()),
+ DebugTypeExtRefs(CGM.getCodeGenOpts().DebugTypeExtRefs),
DBuilder(CGM.getModule()) {
CreateCompileUnit();
}
Index: include/clang/Frontend/CodeGenOptions.def
===================================================================
--- include/clang/Frontend/CodeGenOptions.def
+++ include/clang/Frontend/CodeGenOptions.def
@@ -161,6 +161,9 @@
CODEGENOPT(DebugColumnInfo, 1, 0) ///< Whether or not to use column information
///< in debug info.
+CODEGENOPT(DebugTypeExtRefs, 1, 0) ///< Whether or not debug info should contain
+ ///< external references to a PCH or module.
+
CODEGENOPT(EmitLLVMUseLists, 1, 0) ///< Control whether to serialize use-lists.
/// The user specified number of registers to be used for integral arguments,
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -1133,6 +1133,9 @@
def gsplit_dwarf : Flag<["-"], "gsplit-dwarf">, Group<g_flags_Group>;
def ggnu_pubnames : Flag<["-"], "ggnu-pubnames">, Group<g_flags_Group>;
def gdwarf_aranges : Flag<["-"], "gdwarf-aranges">, Group<g_flags_Group>;
+def gmodules : Flag <["-"], "gmodules">, Group<f_Group>,
+ HelpText<"Generate debug info with external references to clang modules"
+ " or precompiled headers">;
def headerpad__max__install__names : Joined<["-"], "headerpad_max_install_names">;
def help : Flag<["-", "--"], "help">, Flags<[CC1Option,CC1AsOption]>,
HelpText<"Display available options">;
Index: include/clang/Driver/CC1Options.td
===================================================================
--- include/clang/Driver/CC1Options.td
+++ include/clang/Driver/CC1Options.td
@@ -166,6 +166,9 @@
HelpText<"Emit newer GNU style pubnames">;
def arange_sections : Flag<["-"], "arange_sections">,
HelpText<"Emit DWARF .debug_arange sections">;
+def dwarf_ext_refs : Flag<["-"], "dwarf-ext-refs">,
+ HelpText<"Generate debug info with external references to clang modules"
+ " or precompiled headers">;
def fforbid_guard_variables : Flag<["-"], "fforbid-guard-variables">,
HelpText<"Emit an error if a C++ static local initializer would need a guard variable">;
def no_implicit_float : Flag<["-"], "no-implicit-float">,
Index: docs/CommandGuide/clang.rst
===================================================================
--- docs/CommandGuide/clang.rst
+++ docs/CommandGuide/clang.rst
@@ -257,6 +257,13 @@
Generate debug information. Note that Clang debug information works best at -O0.
+.. option:: -gmodules
+
+ Generate debug information that contains external references to
+ types defined in clang modules or precompiled headers instead of
+ emitting redundant debug type information into every object file.
+ This option implies `-fmodule-format=obj`.
+
.. option:: -fstandalone-debug -fno-standalone-debug
Clang supports a number of optimizations to reduce the size of debug
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