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Default to the medium code model in x86 linux #53391

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merged 6 commits into from
Mar 14, 2024
Merged

Default to the medium code model in x86 linux #53391

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6e0dbb1
Default to the medium code model in x86 linux
gbaraldi Feb 19, 2024
32a5628
Merge branch 'master' into gb/large-image
gbaraldi Mar 4, 2024
a0c5c42
Merge branch 'master' into gb/large-image
gbaraldi Mar 8, 2024
4a15148
Add ifdef for LLVM 18 change
gbaraldi Mar 8, 2024
7bdc210
Merge branch 'master' into gb/large-image
gbaraldi Mar 11, 2024
af8ef5d
Update src/aotcompile.cpp
vtjnash Mar 14, 2024
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14 changes: 11 additions & 3 deletions src/aotcompile.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
#include "platform.h"

// target support
#include "llvm/Support/CodeGen.h"
#include <llvm/ADT/Triple.h>
#include <llvm/ADT/Statistic.h>
#include <llvm/Analysis/TargetLibraryInfo.h>
Expand Down Expand Up @@ -1609,10 +1610,11 @@ void jl_dump_native_impl(void *native_code,
if (TheTriple.isOSLinux() || TheTriple.isOSFreeBSD()) {
RelocModel = Reloc::PIC_;
}

CodeModel::Model CMModel = CodeModel::Small;
if (TheTriple.isPPC()) {
// On PPC the small model is limited to 16bit offsets
CMModel = CodeModel::Medium;
if (TheTriple.isPPC() || (TheTriple.isX86() && TheTriple.isArch64Bit() && TheTriple.isOSLinux())) {
// On PPC the small model is limited to 16bit offsets. For very large images the small code model
CMModel = CodeModel::Medium; // isn't good enough on x86 so use Medium, it has no cost because only the image goes in .ldata
}
std::unique_ptr<TargetMachine> SourceTM(
jl_ExecutionEngine->getTarget().createTargetMachine(
Expand Down Expand Up @@ -1655,6 +1657,12 @@ void jl_dump_native_impl(void *native_code,
GlobalVariable::ExternalLinkage,
data, "jl_system_image_data");
sysdata->setAlignment(Align(64));
#if JL_LLVM_VERSION >= 180000
sysdata->setCodeModel(CodeModel::Large);
#else
if (TheTriple.isX86() && TheTriple.isArch64Bit() && TheTriple.isOSLinux())
sysdata->setSection(".ldata");
Comment on lines +1663 to +1664
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IIUC, this is already automatic, once you select Medium code model globally, although can also be opted for explicitly for each variable:
https://llvm.org/doxygen/TargetMachine_8cpp_source.html

Suggested change
if (TheTriple.isX86() && TheTriple.isArch64Bit() && TheTriple.isOSLinux())
sysdata->setSection(".ldata");
sysdata->setCodeModel(CodeModel::Large);

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It wasn't doing it automatically for me :(. Not sure why

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llvm/llvm-project#72078 also the per global option was just added.

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I guess this should have an LLVM_VERSION ifdef here then?

#endif
addComdat(sysdata, TheTriple);
Constant *len = ConstantInt::get(sysimgM.getDataLayout().getIntPtrType(Context), z->size);
addComdat(new GlobalVariable(sysimgM, len->getType(), true,
Expand Down