8000 Update to LLVM 9 by nikic · Pull Request #19 · rust-lang/llvm-project · GitHub
[go: up one dir, main page]
Skip to content

Update to LLVM 9 #19

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 10 commits into from
Jul 11, 2019
Merged

Update to LLVM 9 #19

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
10 commits
Select commit Hold shift + click to select a range
5889534
Add accessors for MCSubtargetInfo CPU and Feature tables
bitshifter Jul 10, 2016
fd5f9e2
Fix compile on dist-i686-linux builder
alexcrichton Jul 28, 2017
606b776
Disable checks for libatomic for now
alexcrichton Jan 24, 2018
69cb0d1
Add knowledge of __rust_{alloc,realloc,dealloc}
nagisa Jun 3, 2017
a4f3260
Fix compile on dist-x86_64-linux builder
alexcrichton Jul 2, 2018
accc618
Compile with /MT on MSVC
alexcrichton Feb 11, 2018
9670dbb
Fix compilation of sanitizers in Rust containers
alexcrichton May 22, 2019
2902abd
Fix sanitizer build without O_CLOEXEC
nikic Jul 8, 2019
ef83c04
[SLP] Optimize getSpillCost(); NFCI
nikic Jul 9, 2019
56b8425
[X86] -fno-plt: use GOT __tls_get_addr only if GOTPCRELX is enabled
MaskRay Jul 11, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Prev Previous commit
[X86] -fno-plt: use GOT __tls_get_addr only if GOTPCRELX is enabled 
Summary:
As of binutils 2.32, ld has a bogus TLS relaxation error when the GD/LD
code sequence using R_X86_64_GOTPCREL (instead of R_X86_64_GOTPCRELX) is
attempted to be relaxed to IE/LE (binutils PR24784). gold and lld are good.

In gcc/config/i386/i386.md, there is a configure-time check of as/ld
support and the GOT relaxation will not be used if as/ld doesn't support
it:

    if (flag_plt || !HAVE_AS_IX86_TLS_GET_ADDR_GOT)
      return "call\t%P2";
    return "call\t{*%p2@GOT(%1)|[DWORD PTR %p2@GOT[%1]]}";

In clang, -DENABLE_X86_RELAX_RELOCATIONS=OFF is the default. The ld.bfd
bogus error can be reproduced with:

    thread_local int a;
    int main() { return a; }

clang -fno-plt -fpic a.cc -fuse-ld=bfd

GOTPCRELX gained relative good support in 2016, which is considered
relatively new.  It is even difficult to conditionally default to
-DENABLE_X86_RELAX_RELOCATIONS=ON due to cross compilation reasons. So
work around the ld.bfd bug by only using GOT when GOTPCRELX is enabled.

Reviewers: dalias, hjl.tools, nikic, rnk

Reviewed By: nikic

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64304

llvm-svn: 365752
  • Loading branch information
@MaskRay @nikic
MaskRay authored and nikic committed Jul 11, 2019
commit 56b8425750e78974fcc8c64429739bc8c2d84f08
9 changes: 8 additions & 1 deletion llvm/lib/Target/X86/X86MCInstLower.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -705,7 +705,14 @@ void X86AsmPrinter::LowerTlsAddr(X86MCInstLower &MCInstLowering,

const MCSymbolRefExpr *Sym = MCSymbolRefExpr::create(
MCInstLowering.GetSymbolFromOperand(MI.getOperand(3)), SRVK, Ctx);
bool UseGot = MMI->getModule()->getRtLibUseGOT();

// As of binutils 2.32, ld has a bogus TLS relaxation error when the GD/LD
// code sequence using R_X86_64_GOTPCREL (instead of R_X86_64_GOTPCRELX) is
// attempted to be relaxed to IE/LE (binutils PR24784). Work around the bug by
// only using GOT when GOTPCRELX is enabled.
// TODO Delete the workaround when GOTPCRELX becomes commonplace.
bool UseGot = MMI->getModule()->getRtLibUseGOT() &&
Ctx.getAsmInfo()->canRelaxRelocations();

if (Is64Bits) {
bool NeedsPadding = SRVK == MCSymbolRefExpr::VK_TLSGD;
Expand Down
13 changes: 11 additions & 2 deletions llvm/test/CodeGen/X86/tls-no-plt.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,10 @@
; RUN: llc < %s -mtriple=i386-linux-musl -relocation-model=pic | FileCheck --check-prefixes=CHECK,X86 %s
; RUN: llc < %s -mtriple=x86_64-linux-musl -relocation-model=pic | FileCheck --check-prefixes=CHECK,X64 %s
; RUN: llc < %s -mtriple=i386-linux-musl -relocation-model=pic -relax-elf-relocations=true | FileCheck --check-prefixes=CHECK,X86 %s
; RUN: llc < %s -mtriple=x86_64-linux-musl -relocation-model=pic -relax-elf-relocations=true | FileCheck --check-prefixes=CHECK,X64 %s

;; If GOTPCRELX is disabled, don't use GOT for __tls_get_addr to work around
;; a ld.bfd bug (binutils PR24784).
; RUN: llc < %s -mtriple=i386-linux-musl -relocation-model=pic | FileCheck --check-prefixes=CHECK,X86-PLT %s
; RUN: llc < %s -mtriple=x86_64-linux-musl -relocation-model=pic | FileCheck --check-prefixes=CHECK,X64-PLT %s

@gd = thread_local global i32 0
@ld = internal thread_local global i32 0
Expand All @@ -9,9 +14,11 @@ entry:
; CHECK-LABEL: get_gd:
; X86: leal gd@TLSGD(%ebx), %eax
; X86: calll *___tls_get_addr@GOT(%ebx)
; X86-PLT: calll ___tls_get_addr@PLT

; X64: leaq gd@TLSGD(%rip), %rdi
; X64: callq *__tls_get_addr@GOTPCREL(%rip)
; X64-PLT: callq __tls_get_addr@PLT
ret i32* @gd
}

Expand All @@ -20,9 +27,11 @@ define i32* @get_ld() {
; CHECK-LABEL: get_ld:
; X86: leal ld@TLSLDM(%ebx), %eax
; X86: calll *___tls_get_addr@GOT(%ebx)
; X86-PLT: calll ___tls_get_addr@PLT

; X64: leaq ld@TLSLD(%rip), %rdi
; X64: callq *__tls_get_addr@GOTPCREL(%rip)
; X64-PLT: callq __tls_get_addr@PLT
ret i32* @ld
}

Expand Down
0