[DebugInfo] Support DWARF v5 source code embedding extension

In DWARF v5 the Line Number Program Header is extensible, allowing values with
new content types. This vendor extension to DWARF v5 allows source text to be
embedded directly in the line tables of the debug line section.

Add new flag (-g[no-]embed-source) to Driver and CC1 which indicates
that source should be passed through to LLVM during CodeGen.

Differential Revision: https://reviews.llvm.org/D42766

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@326102 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/docs/ClangCommandLineReference.rst b/docs/ClangCommandLineReference.rst
index fa429040bef53849d12a269ec5c57037ee8de94d..595909eef077d977223dbc89183c699b152167be 100644 (file)
--- a/docs/ClangCommandLineReference.rst
+++ b/docs/ClangCommandLineReference.rst
@@ -2573,6 +2573,10 @@ Debug information flags
 
 .. option:: -gdwarf-aranges
 
+.. option:: -gembed-source
+
+.. option:: -gno-embed-source
+
 .. option:: -ggnu-pubnames
 
 .. option:: -grecord-gcc-switches, -gno-record-gcc-switches

diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 21d42a54f847c2b7ee7cd6e8bd2cadc44ad8fbfb..04ed098e8935591c21baa3be294a5469ed40ff24 100644 (file)
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -1703,6 +1703,11 @@ def gz : Flag<["-"], "gz">, Group<g_flags_Group>,
     HelpText<"DWARF debug sections compression type">;
 def gz_EQ : Joined<["-"], "gz=">, Group<g_flags_Group>,
     HelpText<"DWARF debug sections compression type">;
+def gembed_source : Flag<["-"], "gembed-source">, Group<g_flags_Group>, Flags<[CC1Option]>,
+    HelpText<"Embed source text in DWARF debug sections">;
+def gno_embed_source : Flag<["-"], "gno-embed-source">, Group<g_flags_Group>,
+    Flags<[DriverOption]>,
+    HelpText<"Restore the default behavior of not embedding source text in DWARF debug sections">;
 def headerpad__max__install__names : Joined<["-"], "headerpad_max_install_names">;
 def help : Flag<["-", "--"], "help">, Flags<[CC1Option,CC1AsOption]>,
   HelpText<"Display available options">;

diff --git a/include/clang/Frontend/CodeGenOptions.def b/include/clang/Frontend/CodeGenOptions.def
index 0e4c4617b220c69709351f3439d2a48af67e1d6c..50addf7ff3e41f6ec4bf4e91020f4da200ec154a 100644 (file)
--- a/include/clang/Frontend/CodeGenOptions.def
+++ b/include/clang/Frontend/CodeGenOptions.def
@@ -318,6 +318,9 @@ CODEGENOPT(GnuPubnames, 1, 0)
 
 CODEGENOPT(NoPLT, 1, 0)
 
+/// Whether to embed source in DWARF debug line section.
+CODEGENOPT(EmbedSource, 1, 0)
+
 #undef CODEGENOPT
 #undef ENUM_CODEGENOPT
 #undef VALUE_CODEGENOPT

diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 3dab8c388438c6888c12f402527dc9c124642386..403957214a65fe5a75fd5813ac47ac5f93676203 100644 (file)
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -385,6 +385,19 @@ CGDebugInfo::computeChecksum(FileID FID, SmallString<32> &Checksum) const {
   return llvm::DIFile::CSK_MD5;
 }
 
+Optional<StringRef> CGDebugInfo::getSource(const SourceManager &SM, FileID FID) {
+  if (!CGM.getCodeGenOpts().EmbedSource)
+    return None;
+
+  bool SourceInvalid = false;
+  StringRef Source = SM.getBufferData(FID, &SourceInvalid);
+
+  if (SourceInvalid)
+    return None;
+
+  return Source;
+}
+
 llvm::DIFile *CGDebugInfo::getOrCreateFile(SourceLocation Loc) {
   if (!Loc.isValid())
     // If Location is not valid then use main input file.
@@ -416,16 +429,19 @@ llvm::DIFile *CGDebugInfo::getOrCreateFile(SourceLocation Loc) {
 
   llvm::DIFile *F = DBuilder.createFile(remapDIPath(PLoc.getFilename()),
                                         remapDIPath(getCurrentDirname()),
-                                        CSInfo);
+                                        CSInfo,
+                                        getSource(SM, SM.getFileID(Loc)));
 
   DIFileCache[fname].reset(F);
   return F;
 }
 
 llvm::DIFile *CGDebugInfo::getOrCreateMainFile() {
-  return DBuilder.createFile(remapDIPath(TheCU->getFilename()),
-                             remapDIPath(TheCU->getDirectory()),
-                             TheCU->getFile()->getChecksum());
+  return DBuilder.createFile(
+      remapDIPath(TheCU->getFilename()),
+      remapDIPath(TheCU->getDirectory()),
+      TheCU->getFile()->getChecksum(),
+      CGM.getCodeGenOpts().EmbedSource ? TheCU->getSource() : None);
 }
 
 std::string CGDebugInfo::remapDIPath(StringRef Path) const {
@@ -558,7 +574,9 @@ void CGDebugInfo::CreateCompileUnit() {
   TheCU = DBuilder.createCompileUnit(
       LangTag,
       DBuilder.createFile(remapDIPath(MainFileName),
-                          remapDIPath(getCurrentDirname()), CSInfo),
+                          remapDIPath(getCurrentDirname()),
+                          CSInfo,
+                          getSource(SM, SM.getMainFileID())),
       Producer, LO.Optimize || CGOpts.PrepareForLTO || CGOpts.EmitSummaryIndex,
       CGOpts.DwarfDebugFlags, RuntimeVers,
       CGOpts.EnableSplitDwarf ? "" : CGOpts.SplitDwarfFile, EmissionKind,
@@ -2108,6 +2126,7 @@ CGDebugInfo::getOrCreateModuleRef(ExternalASTSource::ASTSourceDescriptor Mod,
             : ~1ULL;
     llvm::DIBuilder DIB(CGM.getModule());
     DIB.createCompileUnit(TheCU->getSourceLanguage(),
+                          // TODO: Support "Source" from external AST providers?
                           DIB.createFile(Mod.getModuleName(), Mod.getPath()),
                           TheCU->getProducer(), true, StringRef(), 0,
                           Mod.getASTFile(), llvm::DICompileUnit::FullDebug,

diff --git a/lib/CodeGen/CGDebugInfo.h b/lib/CodeGen/CGDebugInfo.h
index a8b0c613cca65f87557e3abd0e56150c064da237..459d7e00b6fb4de7c733db472acca9cb39f1dac7 100644 (file)
--- a/lib/CodeGen/CGDebugInfo.h
+++ b/lib/CodeGen/CGDebugInfo.h
@@ -502,6 +502,9 @@ private:
   Optional<llvm::DIFile::ChecksumKind>
   computeChecksum(FileID FID, SmallString<32> &Checksum) const;
 
+  /// Get the source of the given file ID.
+  Optional<StringRef> getSource(const SourceManager &SM, FileID FID);
+
   /// Get the file debug info descriptor for the input location.
   llvm::DIFile *getOrCreateFile(SourceLocation Loc);
 

diff --git a/lib/Driver/ToolChains/AMDGPU.h b/lib/Driver/ToolChains/AMDGPU.h
index 36114d0dabc43d72341e8ec37fde5f8646584d53..588c24032b89f0691d23d934197f5244a3831896 100644 (file)
--- a/lib/Driver/ToolChains/AMDGPU.h
+++ b/lib/Driver/ToolChains/AMDGPU.h
@@ -56,7 +56,7 @@ protected:
 public:
   AMDGPUToolChain(const Driver &D, const llvm::Triple &Triple,
                   const llvm::opt::ArgList &Args);
-  unsigned GetDefaultDwarfVersion() const override { return 2; }
+  unsigned GetDefaultDwarfVersion() const override { return 5; }
   bool IsIntegratedAssemblerDefault() const override { return true; }
   llvm::opt::DerivedArgList *
   TranslateArgs(const llvm::opt::DerivedArgList &Args, StringRef BoundArch,

diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp
index a19c5031ce06eef33e5ec441a0428a2e24daea52..a2248ddaa908867fbde6aea97aee112b72377b3c 100644 (file)
--- a/lib/Driver/ToolChains/Clang.cpp
+++ b/lib/Driver/ToolChains/Clang.cpp
@@ -3024,6 +3024,18 @@ static void RenderDebugOptions(const ToolChain &TC, const Driver &D,
   if (DebugInfoKind == codegenoptions::LimitedDebugInfo && NeedFullDebug)
     DebugInfoKind = codegenoptions::FullDebugInfo;
 
+  if (Args.hasFlag(options::OPT_gembed_source, options::OPT_gno_embed_source, false)) {
+    // Source embedding is a vendor extension to DWARF v5. By now we have
+    // checked if a DWARF version was stated explicitly, and have otherwise
+    // fallen back to the target default, so if this is still not at least 5 we
+    // emit an error.
+    if (DWARFVersion < 5)
+      D.Diag(diag::err_drv_argument_only_allowed_with)
+          << Args.getLastArg(options::OPT_gembed_source)->getAsString(Args)
+          << "-gdwarf-5";
+    CmdArgs.push_back("-gembed-source");
+  }
+
   RenderDebugEnablingArgs(Args, CmdArgs, DebugInfoKind, DWARFVersion,
                           DebuggerTuning);
 

diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 443c550bcb4955e450c10a03cd537629e650a03d..4be390b49bc5bd4b29121e3e0f646e43722aec2c 100644 (file)
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -545,6 +545,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.DebugTypeExtRefs = Args.hasArg(OPT_dwarf_ext_refs);
   Opts.DebugExplicitImport = Args.hasArg(OPT_dwarf_explicit_import);
   Opts.DebugFwdTemplateParams = Args.hasArg(OPT_debug_forward_template_params);
+  Opts.EmbedSource = Args.hasArg(OPT_gembed_source);
 
   for (const auto &Arg : Args.getAllArgValues(OPT_fdebug_prefix_map_EQ))
     Opts.DebugPrefixMap.insert(StringRef(Arg).split('='));

diff --git a/test/CodeGen/Inputs/debug-info-embed-source.c b/test/CodeGen/Inputs/debug-info-embed-source.c
new file mode 100644 (file)
index 0000000..2fb55ee
--- /dev/null
+++ b/test/CodeGen/Inputs/debug-info-embed-source.c
@@ -0,0 +1 @@
+void foo() { }

diff --git a/test/CodeGen/debug-info-embed-source.c b/test/CodeGen/debug-info-embed-source.c
new file mode 100644 (file)
index 0000000..3b607b6
--- /dev/null
+++ b/test/CodeGen/debug-info-embed-source.c
@@ -0,0 +1,5 @@
+// RUN: %clang_cc1                -debug-info-kind=limited -emit-llvm %p/Inputs/debug-info-embed-source.c -o - | FileCheck %s --check-prefix=NOEMBED
+// RUN: %clang_cc1 -gembed-source -debug-info-kind=limited -emit-llvm %p/Inputs/debug-info-embed-source.c -o - | FileCheck %s --check-prefix=EMBED
+
+// NOEMBED-NOT: !DIFile({{.*}}source:
+// EMBED: !DIFile({{.*}}source: "void foo() { }\0A"

diff --git a/test/Driver/amdgpu-toolchain.c b/test/Driver/amdgpu-toolchain.c
index 52a71975b7f9a740fb5c2245b24a3c9a1a6314d2..bd6bf7e34189728199d9e63410a32bac457517db 100644 (file)
--- a/test/Driver/amdgpu-toolchain.c
+++ b/test/Driver/amdgpu-toolchain.c
@@ -3,4 +3,4 @@
 // AS_LINK: ld.lld{{.*}} "-shared"
 
 // RUN: %clang -### -g -target amdgcn--amdhsa -mcpu=kaveri %s 2>&1 | FileCheck -check-prefix=DWARF_VER %s
-// DWARF_VER: "-dwarf-version=2"
+// DWARF_VER: "-dwarf-version=5"

diff --git a/test/Driver/debug-options.c b/test/Driver/debug-options.c
index 3bec1e141d10bcf1cbe257b7012a1abdec7d0abd..b3f7aa60e32f4b7bdc41da42b0738ee2896e93cb 100644 (file)
--- a/test/Driver/debug-options.c
+++ b/test/Driver/debug-options.c
@@ -245,3 +245,13 @@
 // RUN: %clang -###                  %s 2>&1 | FileCheck -check-prefix=NOMACRO %s
 // MACRO: "-debug-info-macro"
 // NOMACRO-NOT: "-debug-info-macro"
+//
+// RUN: %clang -### -gdwarf-5 -gembed-source %s 2>&1 | FileCheck -check-prefix=GEMBED_5 %s
+// RUN: %clang -### -gdwarf-2 -gembed-source %s 2>&1 | FileCheck -check-prefix=GEMBED_2 %s
+// RUN: %clang -### -gdwarf-5 -gno-embed-source %s 2>&1 | FileCheck -check-prefix=NOGEMBED_5 %s
+// RUN: %clang -### -gdwarf-2 -gno-embed-source %s 2>&1 | FileCheck -check-prefix=NOGEMBED_2 %s
+//
+// GEMBED_5:  "-gembed-source"
+// GEMBED_2:  error: invalid argument '-gembed-source' only allowed with '-gdwarf-5'
+// NOGEMBED_5-NOT:  "-gembed-source"
+// NOGEMBED_2-NOT:  error: invalid argument '-gembed-source' only allowed with '-gdwarf-5'