[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

llvm-svn: 326102

diff --git a/clang/docs/ClangCommandLineReference.rst b/clang/docs/ClangCommandLineReference.rst
index fa42904..595909e 100644 (file)
--- a/clang/docs/ClangCommandLineReference.rst
+++ b/clang/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/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 21d42a5..04ed098 100644 (file)
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/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/clang/include/clang/Frontend/CodeGenOptions.def b/clang/include/clang/Frontend/CodeGenOptions.def
index 0e4c461..50addf7 100644 (file)
--- a/clang/include/clang/Frontend/CodeGenOptions.def
+++ b/clang/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/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 3dab8c3..4039572 100644 (file)
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/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/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index a8b0c61..459d7e0 100644 (file)
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/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/clang/lib/Driver/ToolChains/AMDGPU.h b/clang/lib/Driver/ToolChains/AMDGPU.h
index 36114d0..588c240 100644 (file)
--- a/clang/lib/Driver/ToolChains/AMDGPU.h
+++ b/clang/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/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index a19c503..a2248dd 100644 (file)
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/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/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 443c550..4be390b 100644 (file)
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/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/clang/test/CodeGen/Inputs/debug-info-embed-source.c b/clang/test/CodeGen/Inputs/debug-info-embed-source.c
new file mode 100644 (file)
index 0000000..2fb55ee
--- /dev/null
+++ b/clang/test/CodeGen/Inputs/debug-info-embed-source.c
@@ -0,0 +1 @@
+void foo() { }

diff --git a/clang/test/CodeGen/debug-info-embed-source.c b/clang/test/CodeGen/debug-info-embed-source.c
new file mode 100644 (file)
index 0000000..3b607b6
--- /dev/null
+++ b/clang/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/clang/test/Driver/amdgpu-toolchain.c b/clang/test/Driver/amdgpu-toolchain.c
index 52a7197..bd6bf7e 100644 (file)
--- a/clang/test/Driver/amdgpu-toolchain.c
+++ b/clang/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/clang/test/Driver/debug-options.c b/clang/test/Driver/debug-options.c
index 3bec1e1..b3f7aa6 100644 (file)
--- a/clang/test/Driver/debug-options.c
+++ b/clang/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'