Temporal merge #432

LawrenceEsswood · 2020-05-26T17:50:14Z

All the changes I have made for CheriOS.

Clang changes:

New safe and unsafe attributes

LLVM changes:

A pass to automatically tag things
Extra tracking for stack objects (safe/unsafe) (not target specific)
New general stack layout rules for safe/unsafe objects (not target specific)
Support for multiple entry points (not target specific)
Extra code generation in the mips backend for CheriOS's extra entry points
A second captable for TLS

LLD changes:

Support for the second captable
CheriOS specific captable layout stuff

clang/lib/Basic/Targets/Mips.h

lld/ELF/Arch/Cheri.cpp

jrtc27 · 2020-05-29T14:30:19Z

Not doing a full review, but you have 3 files that have been made executable, and you have a lot of non-conforming formatting. Please go through the patch yourself and review these kinds of things (clang-format is your friend for the latter).

clang/include/clang/Basic/TargetOptions.h

lld/ELF/Arch/Cheri.h

llvm/lib/Target/Mips/MCTargetDesc/MipsABIInfo.h

clang/lib/CodeGen/CGDecl.cpp

…nstruction

…d to fetch all remaining symbols.

LawrenceEsswood · 2021-10-11T15:08:33Z

I have rebased / gone over the commits with clang-format.

clang/lib/CodeGen/CGDecl.cpp

clang/lib/Sema/SemaDeclAttr.cpp

arichardson · 2021-10-19T15:47:47Z

llvm/lib/Transforms/Scalar/SROA.cpp

@@ -4767,6 +4767,12 @@ bool SROA::splitAlloca(AllocaInst &AI, AllocaSlices &AS) {
    if (AllocaInst *NewAI = rewritePartition(AI, AS, P)) {
      Changed = true;
      if (NewAI != &AI) {
+
+        MDNode *Meta = AI.getMetadata("temporal");


I worry that other passes also drop metadata. I guess if it's only needed for allocas the risk is slightly reduced.

llvm/lib/Transforms/TemporalStacks/TemporalStackPass.cpp

arichardson · 2021-10-19T15:51:56Z

llvm/lib/MC/MCTargetOptions.cpp

@@ -11,6 +11,30 @@
 #include "llvm/Support/CommandLine.h"

 using namespace llvm;
+using namespace escape;
+
+static cl::opt<analysis_type> TemporalType(


Might be better to pass this as a global metadata node in the generated IR? If it's not present the pass isn't run (i.e. the default) and the when compiling for CheriOS clang adds the right metadata.

arichardson · 2021-10-19T15:53:37Z

llvm/lib/MC/MCTargetOptions.cpp

@@ -51,6 +51,12 @@ CheriCapabilityTableABI MCTargetOptions::cheriCapabilityTableABI() {
  return CapTableABI;
 }

+static cl::opt<bool> IsCheriOSABI("is-cherios",


IMO this should be part of the triple (riscv64-unknown-cherios) rather than a hidden -mllvm flag. It adds a bit more work since you need to copy-paste the useful bits of FreeBSD.cpp but is much cleaner than reusing the FreeBSD driver code.

I suppose this depends on if I ever want CheriOS to compose with FreeBSD in some way. i.e. run the CheriOS style calling convention on FreeBSD.

arichardson · 2021-10-19T15:56:15Z

llvm/lib/Target/Mips/MipsSubtarget.cpp

@@ -301,6 +301,7 @@ bool MipsSubtarget::isABI_O32() const { return getABI().IsO32(); }
 bool MipsSubtarget::isABI_CheriPureCap() const {
  return getABI().IsCheriPureCap();
 }
+bool MipsSubtarget::isABI_CheriOS() const { return getABI().IsCheriOS(); }


TM.getTargetTriple().getOS() == llvm::Triple::CheriOS

llvm/lib/Target/Mips/MipsRegisterInfo.cpp

arichardson · 2021-10-19T16:09:20Z

llvm/lib/Target/Mips/MCTargetDesc/MipsABIInfo.cpp

 unsigned MipsABIInfo::GetReturnAddress() const {
  return IsCheriPureCap() ?
    Mips::C17 :
    (ArePtrs64bit() ? Mips::RA_64 : Mips::RA);
 }

+unsigned MipsABIInfo::GetFunctionAddress() const { return Mips::C12; }


Could change those to return MCRegister now.

llvm/lib/Target/Mips/MCTargetDesc/MipsABIInfo.cpp

llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp

llvm/lib/Target/Mips/MipsISelLowering.cpp

nwf reviewed May 29, 2020

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jrtc27 reviewed May 29, 2020

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lld/ELF/Arch/Cheri.cpp Outdated Show resolved Hide resolved

jrtc27 reviewed Jun 1, 2020

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arichardson reviewed Jun 18, 2020

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lld/ELF/Arch/Cheri.h Outdated Show resolved Hide resolved

arichardson reviewed Jun 18, 2020

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lld/ELF/Arch/Cheri.h Show resolved Hide resolved

arichardson reviewed Jun 18, 2020

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lld/ELF/Arch/Cheri.h Show resolved Hide resolved

jrtc27 reviewed Jun 18, 2020

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llvm/lib/Target/Mips/MCTargetDesc/MipsABIInfo.h Outdated Show resolved Hide resolved

LawrenceEsswood changed the base branch from master to dev June 24, 2020 15:37

arichardson force-pushed the dev branch from 7d77577 to c7ab6af Compare July 1, 2020 22:06

LawrenceEsswood force-pushed the temporal_merge branch from 506dfea to 6aab764 Compare August 24, 2020 18:31

arichardson reviewed Aug 25, 2020

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clang/lib/CodeGen/CGDecl.cpp Outdated Show resolved Hide resolved

clang/lib/CodeGen/CGDecl.cpp Outdated Show resolved Hide resolved

LawrenceEsswood force-pushed the temporal_merge branch 2 times, most recently from fc7e35b to 669f902 Compare October 6, 2021 15:50

LawrenceEsswood added 16 commits October 11, 2021 16:05

Add new safe/unsafe attributes to clang

15f0999

Add function to rebuild MapVector

f31c1ca

Have SROA preserve temporal metadata tags

91c2e66

Add escape analysis pass

ecafdfd

Add is-cherios flag to llvm

8bc8bcc

Propagate and track safety of stack objects and seperate their layout

9ba792f

Add support for auxiliary function entries

4fc1858

Add CheriOS specific ABI info

ffe0ce2

Add TLS captable

3eaa79c

Add CHERIOSABI elf flag

3ecc115

Add CheriOS specific aux function entries, stack layout, and return i…

0714edf

…nstruction

CheriOS style jump tables that are function entry relative

b370a1d

Add is-cherios and lto-stats flags

88e5399

Always use reloc model PIC for CheriOS for LTO

88b0e62

CheriOS does not have alignment requirements for segments

168e00b

Have symbol tables record which archives added symbols. Provide metho…

9cd60cc

…d to fetch all remaining symbols.

LawrenceEsswood added 6 commits October 11, 2021 16:06

Track which (if any) TLS segment a section appears in

cd25260

Record which index program headers are assigned

faf4987

Add CheriOS specific aux entries to dynsym if main entry is

9b3d5b6

Add the CheriOS TLS captable

eabc745

Calling getCapSize asserts for non-cheri.

ddab322

Remove defuct default case

db2d723

LawrenceEsswood force-pushed the temporal_merge branch from 669f902 to db2d723 Compare October 11, 2021 15:07

LawrenceEsswood requested review from jrtc27 and arichardson October 11, 2021 15:08

arichardson reviewed Oct 11, 2021

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clang/lib/CodeGen/CGDecl.cpp Outdated Show resolved Hide resolved

clang/lib/Sema/SemaDeclAttr.cpp Outdated Show resolved Hide resolved

Check safe/unsafe attributes are exclusive in proper place

62f28fb

arichardson reviewed Oct 19, 2021

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Lawrence Esswood added 3 commits February 22, 2022 12:36

Remove commented out code

85ad1f4

Use Mips::NoRegister, not 0

77135e6

Move some code

21a1a6b

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Temporal merge #432

Temporal merge #432

LawrenceEsswood commented May 26, 2020

jrtc27 commented May 29, 2020

LawrenceEsswood commented Oct 11, 2021

arichardson Oct 19, 2021

arichardson Oct 19, 2021

arichardson Oct 19, 2021

LawrenceEsswood Oct 19, 2021

arichardson Oct 19, 2021

arichardson Oct 19, 2021

Temporal merge #432

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Temporal merge #432

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LawrenceEsswood commented May 26, 2020

jrtc27 commented May 29, 2020

LawrenceEsswood commented Oct 11, 2021

arichardson Oct 19, 2021

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