[llvm] r234921 - IR: Set -preserve-bc-uselistorder=false by default
David Blaikie
dblaikie at gmail.com
Tue Apr 14 13:22:28 PDT 2015
On Tue, Apr 14, 2015 at 1:18 PM, Duncan P. N. Exon Smith <
dexonsmith at apple.com> wrote:
>
> > On 2015-Apr-14, at 12:41, David Blaikie <dblaikie at gmail.com> wrote:
> >
> >
> >
> > On Tue, Apr 14, 2015 at 12:25 PM, Duncan P. N. Exon Smith <
> dexonsmith at apple.com> wrote:
> >
> > > On 2015-Apr-14, at 11:53, David Blaikie <dblaikie at gmail.com> wrote:
> > >
> > >
> > >
> > > On Tue, Apr 14, 2015 at 11:46 AM, Duncan P. N. Exon Smith <
> dexonsmith at apple.com> wrote:
> > >
> > > > On 2015-Apr-14, at 11:42, David Blaikie <dblaikie at gmail.com> wrote:
> > > >
> > > >
> > > >
> > > > On Tue, Apr 14, 2015 at 11:33 AM, Duncan P. N. Exon Smith <
> dexonsmith at apple.com> wrote:
> > > > Author: dexonsmith
> > > > Date: Tue Apr 14 13:33:00 2015
> > > > New Revision: 234921
> > > >
> > > > URL: http://llvm.org/viewvc/llvm-project?rev=234921&view=rev
> > > > Log:
> > > > IR: Set -preserve-bc-uselistorder=false by default
> > > >
> > > > But keep it on by default in `llvm-as`, `opt`, `bugpoint`,
> `llvm-link`,
> > > > `llvm-extract`, and `LTOCodeGenerator`.
> > > >
> > > > Hmm - what's LTOCodeGenerator used for? If it's a standard library
> utility used in production pipelines it might make more sense for it to
> default-off & users can opt-in when necessary?
> > >
> > > The usual flow for libLTO.dylib is "read bitcode, link, optimize,
> codegen,
> > > write object". Writing bitcode is used, e.g., by `ld -save-temps`.
> > >
> > > LTOCodeGenerator is only used to actually generating bitcode from
> LTO-merged modules?
> >
> > IIRC, that's the only time it outputs bitcode, so that's the only
> > place `-preserve-bc-uselistorder` will have any effect.
> >
> > I'm still a bit concerned about making that the default for what seems
> like a relatively common LLVM-as-a-library surface area.
>
> Is it common?
>
> Anyway, I don't understand the concern here. I thought we'd agreed
> that debug output should preserve use-lists?
>
I think I'm still agreeing - I'm just not sure this is strictly debug
output. It seems like a generic utility (& relatively accessible library
surface area for LLVM) that I'd hesitate baking "this is a debug tool"
assumptions into.
>
> >
> > > Also, what's the deal with global state? (just realizing now that the
> "setPreserveBitcodeUseListOrder" is just a global function, not
> LLVMContext, etc) - that seems like the sort of thing I'd be even more
> inclined to push up into the actual utilities very directly, so there's no
> libraries quietly tweaking this global state in surprising ways.
> >
> > Wrong as it may be, this sort of thing is pervasive in LLVM.
> >
> > With varying degrees of "this is a hack & we'd like to remove it one
> day" depending on what it is exactly (eg: all the global state that we're
> trying to make module state for LTO semantics).
> >
> > But if you have specific ideas, I'm happy to tweak this.
> >
> > I'd imagine a parameter to "createBitcodeWriterPass" (&
> WriteBitcodeToFile) would be one way to avoid the global state in this
> instance.
>
> I'm surprised at how few callers there are. I'll have a go...
>
> > > Not sure what sort of ideas on exceptions to the "avoid global state
> because we're a library" we have for these sort of things & how to limit
> their creep.
> > >
> > > - David
> >
> > I think Chris B. was working on fixing global state in `cl::opt`,
> > but I'm not sure where he is with that.
> >
> > *nod* that'd be one example/part of the sort of stuff I was alluding to.
> >
> > - David
> >
> >
> > >
> > > >
> > > > Part of PR5680.
> > > >
> > > > Modified:
> > > > llvm/trunk/lib/IR/UseListOrder.cpp
> > > > llvm/trunk/lib/LTO/LTOCodeGenerator.cpp
> > > > llvm/trunk/tools/bugpoint/bugpoint.cpp
> > > > llvm/trunk/tools/llvm-as/llvm-as.cpp
> > > > llvm/trunk/tools/llvm-extract/llvm-extract.cpp
> > > > llvm/trunk/tools/llvm-link/llvm-link.cpp
> > > > llvm/trunk/tools/opt/opt.cpp
> > > >
> > > > Modified: llvm/trunk/lib/IR/UseListOrder.cpp
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/UseListOrder.cpp?rev=234921&r1=234920&r2=234921&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/lib/IR/UseListOrder.cpp (original)
> > > > +++ llvm/trunk/lib/IR/UseListOrder.cpp Tue Apr 14 13:33:00 2015
> > > > @@ -19,7 +19,7 @@ using namespace llvm;
> > > > static cl::opt<bool> PreserveBitcodeUseListOrder(
> > > > "preserve-bc-uselistorder",
> > > > cl::desc("Preserve use-list order when writing LLVM bitcode."),
> > > > - cl::init(true), cl::Hidden);
> > > > + cl::init(false), cl::Hidden);
> > > >
> > > > static cl::opt<bool> PreserveAssemblyUseListOrder(
> > > > "preserve-ll-uselistorder",
> > > >
> > > > Modified: llvm/trunk/lib/LTO/LTOCodeGenerator.cpp
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/LTO/LTOCodeGenerator.cpp?rev=234921&r1=234920&r2=234921&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/lib/LTO/LTOCodeGenerator.cpp (original)
> > > > +++ llvm/trunk/lib/LTO/LTOCodeGenerator.cpp Tue Apr 14 13:33:00 2015
> > > > @@ -29,6 +29,7 @@
> > > > #include "llvm/IR/LegacyPassManager.h"
> > > > #include "llvm/IR/Mangler.h"
> > > > #include "llvm/IR/Module.h"
> > > > +#include "llvm/IR/UseListOrder.h"
> > > > #include "llvm/IR/Verifier.h"
> > > > #include "llvm/InitializePasses.h"
> > > > #include "llvm/LTO/LTOModule.h"
> > > > @@ -603,6 +604,10 @@ void LTOCodeGenerator::setCodeGenDebugOp
> > > > }
> > > >
> > > > void LTOCodeGenerator::parseCodeGenDebugOptions() {
> > > > + // Turn on -preserve-bc-uselistorder by default, but let the
> command-line
> > > > + // override it.
> > > > + setPreserveBitcodeUseListOrder(true);
> > > > +
> > > > // if options were requested, set them
> > > > if (!CodegenOptions.empty())
> > > > cl::ParseCommandLineOptions(CodegenOptions.size(),
> > > >
> > > > Modified: llvm/trunk/tools/bugpoint/bugpoint.cpp
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/bugpoint/bugpoint.cpp?rev=234921&r1=234920&r2=234921&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/tools/bugpoint/bugpoint.cpp (original)
> > > > +++ llvm/trunk/tools/bugpoint/bugpoint.cpp Tue Apr 14 13:33:00 2015
> > > > @@ -18,6 +18,7 @@
> > > > #include "llvm/IR/LLVMContext.h"
> > > > #include "llvm/IR/LegacyPassManager.h"
> > > > #include "llvm/IR/LegacyPassNameParser.h"
> > > > +#include "llvm/IR/UseListOrder.h"
> > > > #include "llvm/LinkAllIR.h"
> > > > #include "llvm/LinkAllPasses.h"
> > > > #include "llvm/Support/CommandLine.h"
> > > > @@ -136,6 +137,10 @@ int main(int argc, char **argv) {
> > > > polly::initializePollyPasses(Registry);
> > > > #endif
> > > >
> > > > + // Turn on -preserve-bc-uselistorder by default, but let the
> command-line
> > > > + // override it.
> > > > + setPreserveBitcodeUseListOrder(true);
> > > > +
> > > > cl::ParseCommandLineOptions(argc, argv,
> > > > "LLVM automatic testcase reducer.
> See\nhttp://"
> > > > "llvm.org/cmds/bugpoint.html"
> > > >
> > > > Modified: llvm/trunk/tools/llvm-as/llvm-as.cpp
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-as/llvm-as.cpp?rev=234921&r1=234920&r2=234921&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/tools/llvm-as/llvm-as.cpp (original)
> > > > +++ llvm/trunk/tools/llvm-as/llvm-as.cpp Tue Apr 14 13:33:00 2015
> > > > @@ -19,6 +19,7 @@
> > > > #include "llvm/AsmParser/Parser.h"
> > > > #include "llvm/Bitcode/ReaderWriter.h"
> > > > #include "llvm/IR/Module.h"
> > > > +#include "llvm/IR/UseListOrder.h"
> > > > #include "llvm/IR/Verifier.h"
> > > > #include "llvm/Support/CommandLine.h"
> > > > #include "llvm/Support/FileSystem.h"
> > > > @@ -90,6 +91,11 @@ int main(int argc, char **argv) {
> > > > PrettyStackTraceProgram X(argc, argv);
> > > > LLVMContext &Context = getGlobalContext();
> > > > llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
> > > > +
> > > > + // Turn on -preserve-bc-uselistorder by default, but let the
> command-line
> > > > + // override it.
> > > > + setPreserveBitcodeUseListOrder(true);
> > > > +
> > > > cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc
> assembler\n");
> > > >
> > > > // Parse the file now...
> > > >
> > > > Modified: llvm/trunk/tools/llvm-extract/llvm-extract.cpp
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-extract/llvm-extract.cpp?rev=234921&r1=234920&r2=234921&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/tools/llvm-extract/llvm-extract.cpp (original)
> > > > +++ llvm/trunk/tools/llvm-extract/llvm-extract.cpp Tue Apr 14
> 13:33:00 2015
> > > > @@ -19,6 +19,7 @@
> > > > #include "llvm/IR/IRPrintingPasses.h"
> > > > #include "llvm/IR/LLVMContext.h"
> > > > #include "llvm/IR/Module.h"
> > > > +#include "llvm/IR/UseListOrder.h"
> > > > #include "llvm/IRReader/IRReader.h"
> > > > #include "llvm/IR/LegacyPassManager.h"
> > > > #include "llvm/Support/CommandLine.h"
> > > > @@ -97,6 +98,11 @@ int main(int argc, char **argv) {
> > > >
> > > > LLVMContext &Context = getGlobalContext();
> > > > llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
> > > > +
> > > > + // Turn on -preserve-bc-uselistorder by default, but let the
> command-line
> > > > + // override it.
> > > > + setPreserveBitcodeUseListOrder(true);
> > > > +
> > > > cl::ParseCommandLineOptions(argc, argv, "llvm extractor\n");
> > > >
> > > > // Use lazy loading, since we only care about selected global
> values.
> > > >
> > > > Modified: llvm/trunk/tools/llvm-link/llvm-link.cpp
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-link/llvm-link.cpp?rev=234921&r1=234920&r2=234921&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/tools/llvm-link/llvm-link.cpp (original)
> > > > +++ llvm/trunk/tools/llvm-link/llvm-link.cpp Tue Apr 14 13:33:00 2015
> > > > @@ -20,6 +20,7 @@
> > > > #include "llvm/IR/DiagnosticPrinter.h"
> > > > #include "llvm/IR/LLVMContext.h"
> > > > #include "llvm/IR/Module.h"
> > > > +#include "llvm/IR/UseListOrder.h"
> > > > #include "llvm/IR/Verifier.h"
> > > > #include "llvm/IRReader/IRReader.h"
> > > > #include "llvm/Support/CommandLine.h"
> > > > @@ -104,6 +105,11 @@ int main(int argc, char **argv) {
> > > >
> > > > LLVMContext &Context = getGlobalContext();
> > > > llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
> > > > +
> > > > + // Turn on -preserve-bc-uselistorder by default, but let the
> command-line
> > > > + // override it.
> > > > + setPreserveBitcodeUseListOrder(true);
> > > > +
> > > > cl::ParseCommandLineOptions(argc, argv, "llvm linker\n");
> > > >
> > > > auto Composite = make_unique<Module>("llvm-link", Context);
> > > >
> > > > Modified: llvm/trunk/tools/opt/opt.cpp
> > > > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/opt/opt.cpp?rev=234921&r1=234920&r2=234921&view=diff
> > > >
> ==============================================================================
> > > > --- llvm/trunk/tools/opt/opt.cpp (original)
> > > > +++ llvm/trunk/tools/opt/opt.cpp Tue Apr 14 13:33:00 2015
> > > > @@ -30,6 +30,7 @@
> > > > #include "llvm/IR/LLVMContext.h"
> > > > #include "llvm/IR/LegacyPassNameParser.h"
> > > > #include "llvm/IR/Module.h"
> > > > +#include "llvm/IR/UseListOrder.h"
> > > > #include "llvm/IR/Verifier.h"
> > > > #include "llvm/IRReader/IRReader.h"
> > > > #include "llvm/InitializePasses.h"
> > > > @@ -344,6 +345,10 @@ int main(int argc, char **argv) {
> > > > polly::initializePollyPasses(Registry);
> > > > #endif
> > > >
> > > > + // Turn on -preserve-bc-uselistorder by default, but let the
> command-line
> > > > + // override it.
> > > > + setPreserveBitcodeUseListOrder(true);
> > > > +
> > > > cl::ParseCommandLineOptions(argc, argv,
> > > > "llvm .bc -> .bc modular optimizer and analysis printer\n");
> > > >
> > > >
> > > >
> > > > _______________________________________________
> > > > llvm-commits mailing list
> > > > llvm-commits at cs.uiuc.edu
> > > > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> > > >
>
>
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