[+cfe-commits now that this has a patch.]
On 20 October 2011 14:59, Nick Lewycky <[email protected]> wrote:
> On 20 October 2011 14:55, Chandler Carruth <[email protected]> wrote:
>
>> On Thu, Oct 20, 2011 at 2:03 PM, Nick Lewycky <[email protected]>wrote:
>>
>>> To understand why, you first need to know that we run builds on hermetic
>>> build machines.
>>
>>
>> I'm not really sure why our build system is relevant here.
>>
>
> Only because there are ways to fix that problem which would still break
> caching in our build system. I wanted to steer us away from that.
>
>
>> This has been a problem for me many times using very mundane and ordinary
>> build systems. If I build on machine X and then copy the binary to machine
>> Y, it can't find the source code if it is stored in a different directory,
>> even if the directory structure is entirely compatible.
>>
>> Why can't we follow GCC's lead here, and use PWD (when on a system with
>> such a concept) as the basis for DW_AT_comp_dir? I think what I'm missing is
>> why doing that causes problems...
>>
>
> Works for me. I just want agreement for what to do (flag, using PWD,
> whatever). I honestly don't care how it works as long as it works. I can
> propose a patch using PWD if you want, the plumbing through -cc1 will be the
> same either way.
>
Ok, here's a patch that passes PWD through from the driver into the .bc, and
it comes out in the .o files. Yay!
Please review!
Nick
Nick
>
> Chris's objections (which seem reasonable) are to *always* using PWD. To be
>> clear, I'm not suggesting that. I'm suggesting that the Clang driver, which
>> is already quite aware of the user's shell, can inspect PWD and getcwd and
>> consult any other oracle needed to determine a valid working directory, and
>> then pass it via an internal-only flag to the CC1 layer IFF it differs from
>> getcwd.
>>
>
>
Index: include/clang/Frontend/CodeGenOptions.h
===================================================================
--- include/clang/Frontend/CodeGenOptions.h (revision 142623)
+++ include/clang/Frontend/CodeGenOptions.h (working copy)
@@ -115,6 +115,9 @@
/// Enable additional debugging information.
std::string DebugPass;
+ /// The string to embed in debug information as the current working directory.
+ std::string DwarfCompilationDir;
+
/// The string to embed in the debug information for the compile unit, if
/// non-empty.
std::string DwarfDebugFlags;
Index: include/clang/Driver/CC1Options.td
===================================================================
--- include/clang/Driver/CC1Options.td (revision 142623)
+++ include/clang/Driver/CC1Options.td (working copy)
@@ -110,6 +110,8 @@
HelpText<"Don't run the LLVM IR verifier pass">;
def disable_red_zone : Flag<"-disable-red-zone">,
HelpText<"Do not emit code that uses the red zone.">;
+def fdwarf_compilation_dir : Separate<"-fdwarf-compilation-dir">,
+ HelpText<"The string to embed in the Dwarf compilation directory record.">;
def dwarf_debug_flags : Separate<"-dwarf-debug-flags">,
HelpText<"The string to embed in the Dwarf debug flags record.">;
def fforbid_guard_variables : Flag<"-fforbid-guard-variables">,
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp (revision 142623)
+++ lib/Frontend/CompilerInvocation.cpp (working copy)
@@ -131,6 +131,10 @@
Res.push_back("-disable-llvm-optzns");
if (Opts.DisableRedZone)
Res.push_back("-disable-red-zone");
+ if (!Opts.DwarfCompilationDir.empty()) {
+ Res.push_back("-fdwarf-compilation-dir");
+ Res.push_back(Opts.DwarfCompilationDir);
+ }
if (!Opts.DwarfDebugFlags.empty()) {
Res.push_back("-dwarf-debug-flags");
Res.push_back(Opts.DwarfDebugFlags);
@@ -1071,6 +1075,7 @@
Opts.EmitGcovArcs = Args.hasArg(OPT_femit_coverage_data);
Opts.EmitGcovNotes = Args.hasArg(OPT_femit_coverage_notes);
Opts.CoverageFile = Args.getLastArgValue(OPT_coverage_file);
+ Opts.DwarfCompilationDir = Args.getLastArgValue(OPT_fdwarf_compilation_dir);
if (Arg *A = Args.getLastArg(OPT_fobjc_dispatch_method_EQ)) {
StringRef Name = A->getValue(Args);
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp (revision 142623)
+++ lib/Driver/Tools.cpp (working copy)
@@ -1625,6 +1625,12 @@
if (ShouldDisableDwarfDirectory(Args, getToolChain()))
CmdArgs.push_back("-fno-dwarf-directory-asm");
+ if (const char *pwd = getenv("PWD")) {
+ std::string CompDir = pwd;
+ CmdArgs.push_back("-fdwarf-compilation-dir");
+ CmdArgs.push_back(Args.MakeArgString(CompDir));
+ }
+
if (Arg *A = Args.getLastArg(options::OPT_ftemplate_depth_)) {
CmdArgs.push_back("-ftemplate-depth");
CmdArgs.push_back(A->getValue(Args));
Index: lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- lib/CodeGen/CGDebugInfo.cpp (revision 142623)
+++ lib/CodeGen/CGDebugInfo.cpp (working copy)
@@ -250,6 +250,8 @@
}
StringRef CGDebugInfo::getCurrentDirname() {
+ if (!CGM.getCodeGenOpts().DwarfCompilationDir.empty())
+ return CGM.getCodeGenOpts().DwarfCompilationDir;
if (!CWDName.empty())
return CWDName;
llvm::SmallString<256> CWD;
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