[llvm] r304882 - [ARM] Create relocations for unconditional branches.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Wed Jun 7 01:54:48 PDT 2017
Author: fhahn
Date: Wed Jun 7 03:54:47 2017
New Revision: 304882
URL: http://llvm.org/viewvc/llvm-project?rev=304882&view=rev
Log:
[ARM] Create relocations for unconditional branches.
Summary:
Relocations are required for unconditional branches to function symbols with
different execution mode. Without this patch, incorrect branches are
generated for tail calls between functions with different execution
mode.
Reviewers: peter.smith, rafael, echristo, kristof.beyls
Reviewed By: peter.smith
Subscribers: aemerson, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D33898
Added:
llvm/trunk/test/MC/ARM/arm-thumb-tail-call.ll
Modified:
llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
Modified: llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp?rev=304882&r1=304881&r2=304882&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp (original)
+++ llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp Wed Jun 7 03:54:47 2017
@@ -748,13 +748,18 @@ void ARMAsmBackend::processFixupValue(co
// linker can handle it. GNU AS produces an error in this case.
if (Sym->isExternal() || Value >= 0x400004)
IsResolved = false;
- // When an ARM function is called from a Thumb function, produce a
- // relocation so the linker will use the correct branch instruction for ELF
- // binaries.
- if (Sym->isELF()) {
- unsigned Type = dyn_cast<MCSymbolELF>(Sym)->getType();
- if ((Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC) &&
- !Asm.isThumbFunc(Sym))
+ }
+ // Create relocations for unconditional branches to function symbols with
+ // different execution mode in ELF binaries.
+ if (Sym && Sym->isELF()) {
+ unsigned Type = dyn_cast<MCSymbolELF>(Sym)->getType();
+ if ((Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)) {
+ unsigned FixupKind = Fixup.getKind() ;
+ if (Asm.isThumbFunc(Sym) && (FixupKind == ARM::fixup_arm_uncondbranch))
+ IsResolved = false;
+ if (!Asm.isThumbFunc(Sym) && (FixupKind == ARM::fixup_arm_thumb_br ||
+ FixupKind == ARM::fixup_arm_thumb_bl ||
+ FixupKind == ARM::fixup_t2_uncondbranch))
IsResolved = false;
}
}
Added: llvm/trunk/test/MC/ARM/arm-thumb-tail-call.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ARM/arm-thumb-tail-call.ll?rev=304882&view=auto
==============================================================================
--- llvm/trunk/test/MC/ARM/arm-thumb-tail-call.ll (added)
+++ llvm/trunk/test/MC/ARM/arm-thumb-tail-call.ll Wed Jun 7 03:54:47 2017
@@ -0,0 +1,25 @@
+; RUN: llc -O0 < %s -mtriple armv7-linux-gnueabi -o - \
+; RUN: | llvm-mc -triple armv7-linux-gnueabi -filetype=obj -o - \
+; RUN: | llvm-readobj -r | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
+target triple = "armv7--linux-gnueabihf"
+
+define internal i32 @arm_fn() #1 {
+ %1 = tail call i32 @thumb_fn()
+ ret i32 %1
+}
+
+define internal i32 @thumb_fn() #2 {
+ %1 = tail call i32 @arm_fn()
+ ret i32 %1
+}
+
+attributes #1 = { "target-features"="-thumb-mode" }
+attributes #2 = { "target-features"="+thumb-mode" }
+
+; CHECK: Relocations [
+; CHECK-NEXT: Section (3) .rel.text {
+; CHECK-NEXT: 0x0 R_ARM_JUMP24 thumb_fn 0x0
+; CHECK-NEXT: 0x4 R_ARM_THM_JUMP24 arm_fn 0x0
+; CHECK-NEXT: }
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