[llvm] r235227 - Compute A-B when A or B is weak.
Rafael Espindola
rafael.espindola at gmail.com
Fri Apr 17 14:15:18 PDT 2015
Author: rafael
Date: Fri Apr 17 16:15:17 2015
New Revision: 235227
URL: http://llvm.org/viewvc/llvm-project?rev=235227&view=rev
Log:
Compute A-B when A or B is weak.
Similar to r235222, but for the weak symbol case.
In an "ideal" assembler/object format an expression would always refer to the
final value and A-B would only be computed from a section in the same
comdat as A and B with A and B strong.
Unfortunately that is not the case with debug info on ELF, so we need an
heuristic. Since we need an heuristic, we may as well use the same one as
gas:
* call weak_sym : produces a relocation, even if in the same section.
* A - weak_sym and weak_sym -A: don't produce a relocation if we can
compute it.
This fixes pr23272 and changes the fix of pr22815 to match what gas does.
Removed:
llvm/trunk/test/MC/ELF/weak-diff2.s
Modified:
llvm/trunk/include/llvm/MC/MCMachObjectWriter.h
llvm/trunk/include/llvm/MC/MCObjectWriter.h
llvm/trunk/lib/MC/ELFObjectWriter.cpp
llvm/trunk/lib/MC/MCAssembler.cpp
llvm/trunk/lib/MC/MCObjectWriter.cpp
llvm/trunk/lib/MC/MachObjectWriter.cpp
llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp
llvm/trunk/test/MC/ELF/weak-diff.s
Modified: llvm/trunk/include/llvm/MC/MCMachObjectWriter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCMachObjectWriter.h?rev=235227&r1=235226&r2=235227&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCMachObjectWriter.h (original)
+++ llvm/trunk/include/llvm/MC/MCMachObjectWriter.h Fri Apr 17 16:15:17 2015
@@ -264,7 +264,6 @@ public:
bool IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
const MCSymbolData &DataA,
- const MCSymbolData *DataB,
const MCFragment &FB,
bool InSet,
bool IsPCRel) const override;
Modified: llvm/trunk/include/llvm/MC/MCObjectWriter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCObjectWriter.h?rev=235227&r1=235226&r2=235227&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCObjectWriter.h (original)
+++ llvm/trunk/include/llvm/MC/MCObjectWriter.h Fri Apr 17 16:15:17 2015
@@ -94,7 +94,6 @@ public:
virtual bool IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
const MCSymbolData &DataA,
- const MCSymbolData *DataB,
const MCFragment &FB,
bool InSet,
bool IsPCRel) const;
Modified: llvm/trunk/lib/MC/ELFObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/ELFObjectWriter.cpp?rev=235227&r1=235226&r2=235227&view=diff
==============================================================================
--- llvm/trunk/lib/MC/ELFObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/ELFObjectWriter.cpp Fri Apr 17 16:15:17 2015
@@ -275,7 +275,6 @@ class ELFObjectWriter : public MCObjectW
bool
IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
const MCSymbolData &DataA,
- const MCSymbolData *DataB,
const MCFragment &FB,
bool InSet,
bool IsPCRel) const override;
@@ -1669,13 +1668,15 @@ void ELFObjectWriter::WriteObject(MCAsse
}
bool ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
- const MCAssembler &Asm, const MCSymbolData &DataA,
- const MCSymbolData *DataB, const MCFragment &FB, bool InSet,
- bool IsPCRel) const {
- if (!InSet && (::isWeak(DataA) || (DataB && ::isWeak(*DataB))))
- return false;
- return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
- Asm, DataA, DataB, FB, InSet, IsPCRel);
+ const MCAssembler &Asm, const MCSymbolData &DataA, const MCFragment &FB,
+ bool InSet, bool IsPCRel) const {
+ if (IsPCRel) {
+ assert(!InSet);
+ if (::isWeak(DataA))
+ return false;
+ }
+ return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(Asm, DataA, FB,
+ InSet, IsPCRel);
}
bool ELFObjectWriter::isWeak(const MCSymbolData &SD) const {
Modified: llvm/trunk/lib/MC/MCAssembler.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAssembler.cpp?rev=235227&r1=235226&r2=235227&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCAssembler.cpp (original)
+++ llvm/trunk/lib/MC/MCAssembler.cpp Fri Apr 17 16:15:17 2015
@@ -504,7 +504,7 @@ bool MCAssembler::evaluateFixup(const MC
} else {
const MCSymbolData &DataA = getSymbolData(SA);
IsResolved = getWriter().IsSymbolRefDifferenceFullyResolvedImpl(
- *this, DataA, nullptr, *DF, false, true);
+ *this, DataA, *DF, false, true);
}
}
} else {
Modified: llvm/trunk/lib/MC/MCObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCObjectWriter.cpp?rev=235227&r1=235226&r2=235227&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/MCObjectWriter.cpp Fri Apr 17 16:15:17 2015
@@ -36,13 +36,12 @@ bool MCObjectWriter::IsSymbolRefDifferen
return false;
return IsSymbolRefDifferenceFullyResolvedImpl(
- Asm, DataA, &DataB, *DataB.getFragment(), InSet, false);
+ Asm, DataA, *DataB.getFragment(), InSet, false);
}
bool MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
- const MCAssembler &Asm, const MCSymbolData &DataA,
- const MCSymbolData *DataB, const MCFragment &FB, bool InSet,
- bool IsPCRel) const {
+ const MCAssembler &Asm, const MCSymbolData &DataA, const MCFragment &FB,
+ bool InSet, bool IsPCRel) const {
const MCSection &SecA = DataA.getSymbol().getSection();
const MCSection &SecB = FB.getParent()->getSection();
// On ELF and COFF A - B is absolute if A and B are in the same section.
Modified: llvm/trunk/lib/MC/MachObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MachObjectWriter.cpp?rev=235227&r1=235226&r2=235227&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MachObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/MachObjectWriter.cpp Fri Apr 17 16:15:17 2015
@@ -669,13 +669,9 @@ void MachObjectWriter::ExecutePostLayout
BindIndirectSymbols(Asm);
}
-bool MachObjectWriter::
-IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
- const MCSymbolData &DataA,
- const MCSymbolData *DataB,
- const MCFragment &FB,
- bool InSet,
- bool IsPCRel) const {
+bool MachObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
+ const MCAssembler &Asm, const MCSymbolData &DataA, const MCFragment &FB,
+ bool InSet, bool IsPCRel) const {
if (InSet)
return true;
Modified: llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp?rev=235227&r1=235226&r2=235227&view=diff
==============================================================================
--- llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp Fri Apr 17 16:15:17 2015
@@ -172,7 +172,6 @@ public:
bool IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
const MCSymbolData &DataA,
- const MCSymbolData *DataB,
const MCFragment &FB, bool InSet,
bool IsPCRel) const override;
@@ -649,17 +648,16 @@ void WinCOFFObjectWriter::ExecutePostLay
}
bool WinCOFFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
- const MCAssembler &Asm, const MCSymbolData &DataA,
- const MCSymbolData *DataB, const MCFragment &FB, bool InSet,
- bool IsPCRel) const {
+ const MCAssembler &Asm, const MCSymbolData &DataA, const MCFragment &FB,
+ bool InSet, bool IsPCRel) const {
// MS LINK expects to be able to replace all references to a function with a
// thunk to implement their /INCREMENTAL feature. Make sure we don't optimize
// away any relocations to functions.
if ((((DataA.getFlags() & COFF::SF_TypeMask) >> COFF::SF_TypeShift) >>
COFF::SCT_COMPLEX_TYPE_SHIFT) == COFF::IMAGE_SYM_DTYPE_FUNCTION)
return false;
- return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(
- Asm, DataA, DataB, FB, InSet, IsPCRel);
+ return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(Asm, DataA, FB,
+ InSet, IsPCRel);
}
bool WinCOFFObjectWriter::isWeak(const MCSymbolData &SD) const {
Modified: llvm/trunk/test/MC/ELF/weak-diff.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/weak-diff.s?rev=235227&r1=235226&r2=235227&view=diff
==============================================================================
--- llvm/trunk/test/MC/ELF/weak-diff.s (original)
+++ llvm/trunk/test/MC/ELF/weak-diff.s Fri Apr 17 16:15:17 2015
@@ -1,6 +1,10 @@
-// RUN: not llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o %t 2>&1 | FileCheck %s
+// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu < %s | llvm-readobj -r | FileCheck %s
-// CHECK: error: Cannot represent a subtraction with a weak symbol
+// CHECK: Relocations [
+// CHECK-NEXT: Section ({{.*}}) .rela.text {
+// CHECK-NEXT: 0x1D R_X86_64_PC32 f2 0xFFFFFFFFFFFFFFFC
+// CHECK-NEXT: }
+// CHECK-NEXT: ]
.weak f
.weak g
@@ -10,3 +14,13 @@ g:
nop
.quad g - f
+
+
+.weak f2
+f2:
+ nop
+g2:
+ nop
+.quad g2 - f2
+.quad f2 - g2
+call f2
Removed: llvm/trunk/test/MC/ELF/weak-diff2.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/weak-diff2.s?rev=235226&view=auto
==============================================================================
--- llvm/trunk/test/MC/ELF/weak-diff2.s (original)
+++ llvm/trunk/test/MC/ELF/weak-diff2.s (removed)
@@ -1,10 +0,0 @@
-// RUN: not llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o %t 2>&1 | FileCheck %s
-
-// CHECK: error: Cannot represent a subtraction with a weak symbol
-
-.weak f
-f:
- nop
-g:
- nop
-.quad g - f
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