[llvm] r233898 - Revert r233595, "MC: For variable symbols, maintain MCSymbol::Section as a cache."
Peter Collingbourne
peter at pcc.me.uk
Thu Apr 2 00:02:52 PDT 2015
Author: pcc
Date: Thu Apr 2 02:02:51 2015
New Revision: 233898
URL: http://llvm.org/viewvc/llvm-project?rev=233898&view=rev
Log:
Revert r233595, "MC: For variable symbols, maintain MCSymbol::Section as a cache."
Removed:
llvm/trunk/test/MC/ELF/alias-resolve.s
Modified:
llvm/trunk/include/llvm/MC/MCMachObjectWriter.h
llvm/trunk/include/llvm/MC/MCSymbol.h
llvm/trunk/lib/MC/MCExpr.cpp
llvm/trunk/lib/MC/MCSymbol.cpp
llvm/trunk/lib/MC/MachObjectWriter.cpp
llvm/trunk/lib/Target/X86/X86AsmPrinter.cpp
llvm/trunk/test/MC/ELF/alias.s
llvm/trunk/test/MC/MachO/ARM/aliased-symbols.s
Modified: llvm/trunk/include/llvm/MC/MCMachObjectWriter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCMachObjectWriter.h?rev=233898&r1=233897&r2=233898&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCMachObjectWriter.h (original)
+++ llvm/trunk/include/llvm/MC/MCMachObjectWriter.h Thu Apr 2 02:02:51 2015
@@ -257,6 +257,8 @@ public:
void computeSectionAddresses(const MCAssembler &Asm,
const MCAsmLayout &Layout);
+ void markAbsoluteVariableSymbols(MCAssembler &Asm,
+ const MCAsmLayout &Layout);
void ExecutePostLayoutBinding(MCAssembler &Asm,
const MCAsmLayout &Layout) override;
Modified: llvm/trunk/include/llvm/MC/MCSymbol.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCSymbol.h?rev=233898&r1=233897&r2=233898&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCSymbol.h (original)
+++ llvm/trunk/include/llvm/MC/MCSymbol.h Thu Apr 2 02:02:51 2015
@@ -15,7 +15,6 @@
#define LLVM_MC_MCSYMBOL_H
#include "llvm/ADT/StringRef.h"
-#include "llvm/MC/MCExpr.h"
#include "llvm/Support/Compiler.h"
namespace llvm {
@@ -43,9 +42,8 @@ namespace llvm {
/// Section - The section the symbol is defined in. This is null for
/// undefined symbols, and the special AbsolutePseudoSection value for
- /// absolute symbols. If this is a variable symbol, this caches the
- /// variable value's section.
- mutable const MCSection *Section;
+ /// absolute symbols.
+ const MCSection *Section;
/// Value - If non-null, the value for a variable symbol.
const MCExpr *Value;
@@ -70,12 +68,6 @@ namespace llvm {
MCSymbol(const MCSymbol&) = delete;
void operator=(const MCSymbol&) = delete;
- const MCSection *getSectionPtr() const {
- if (Section || !Value)
- return Section;
- return Section = Value->FindAssociatedSection();
- }
-
public:
/// getName - Get the symbol name.
StringRef getName() const { return Name; }
@@ -111,7 +103,7 @@ namespace llvm {
///
/// Defined symbols are either absolute or in some section.
bool isDefined() const {
- return getSectionPtr() != nullptr;
+ return Section != nullptr;
}
/// isInSection - Check if this symbol is defined in some section (i.e., it
@@ -127,27 +119,27 @@ namespace llvm {
/// isAbsolute - Check if this is an absolute symbol.
bool isAbsolute() const {
- return getSectionPtr() == AbsolutePseudoSection;
+ return Section == AbsolutePseudoSection;
}
/// getSection - Get the section associated with a defined, non-absolute
/// symbol.
const MCSection &getSection() const {
assert(isInSection() && "Invalid accessor!");
- return *getSectionPtr();
+ return *Section;
}
/// setSection - Mark the symbol as defined in the section \p S.
- void setSection(const MCSection &S) {
- assert(!isVariable() && "Cannot set section of variable");
- Section = &S;
- }
+ void setSection(const MCSection &S) { Section = &S; }
/// setUndefined - Mark the symbol as undefined.
void setUndefined() {
Section = nullptr;
}
+ /// setAbsolute - Mark the symbol as absolute.
+ void setAbsolute() { Section = AbsolutePseudoSection; }
+
/// @}
/// @name Variable Symbols
/// @{
Modified: llvm/trunk/lib/MC/MCExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCExpr.cpp?rev=233898&r1=233897&r2=233898&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCExpr.cpp (original)
+++ llvm/trunk/lib/MC/MCExpr.cpp Thu Apr 2 02:02:51 2015
@@ -775,9 +775,6 @@ const MCSection *MCExpr::FindAssociatedS
if (RHS_S == MCSymbol::AbsolutePseudoSection)
return LHS_S;
- if (BE->getOpcode() == MCBinaryExpr::Sub)
- return MCSymbol::AbsolutePseudoSection;
-
// Otherwise, return the first non-null section.
return LHS_S ? LHS_S : RHS_S;
}
Modified: llvm/trunk/lib/MC/MCSymbol.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCSymbol.cpp?rev=233898&r1=233897&r2=233898&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCSymbol.cpp (original)
+++ llvm/trunk/lib/MC/MCSymbol.cpp Thu Apr 2 02:02:51 2015
@@ -55,7 +55,13 @@ void MCSymbol::setVariableValue(const MC
assert(!IsUsed && "Cannot set a variable that has already been used.");
assert(Value && "Invalid variable value!");
this->Value = Value;
- this->Section = nullptr;
+
+ // Variables should always be marked as in the same "section" as the value.
+ const MCSection *Section = Value->FindAssociatedSection();
+ if (Section)
+ setSection(*Section);
+ else
+ setUndefined();
}
void MCSymbol::print(raw_ostream &OS) const {
Modified: llvm/trunk/lib/MC/MachObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MachObjectWriter.cpp?rev=233898&r1=233897&r2=233898&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MachObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/MachObjectWriter.cpp Thu Apr 2 02:02:51 2015
@@ -649,12 +649,33 @@ void MachObjectWriter::computeSectionAdd
}
}
+void MachObjectWriter::markAbsoluteVariableSymbols(MCAssembler &Asm,
+ const MCAsmLayout &Layout) {
+ for (MCSymbolData &SD : Asm.symbols()) {
+ if (!SD.getSymbol().isVariable())
+ continue;
+
+ // Is the variable is a symbol difference (SA - SB + C) expression,
+ // and neither symbol is external, mark the variable as absolute.
+ const MCExpr *Expr = SD.getSymbol().getVariableValue();
+ MCValue Value;
+ if (Expr->EvaluateAsRelocatable(Value, &Layout, nullptr)) {
+ if (Value.getSymA() && Value.getSymB())
+ const_cast<MCSymbol*>(&SD.getSymbol())->setAbsolute();
+ }
+ }
+}
+
void MachObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
const MCAsmLayout &Layout) {
computeSectionAddresses(Asm, Layout);
// Create symbol data for any indirect symbols.
BindIndirectSymbols(Asm);
+
+ // Mark symbol difference expressions in variables (from .set or = directives)
+ // as absolute.
+ markAbsoluteVariableSymbols(Asm, Layout);
}
bool MachObjectWriter::
Modified: llvm/trunk/lib/Target/X86/X86AsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86AsmPrinter.cpp?rev=233898&r1=233897&r2=233898&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86AsmPrinter.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86AsmPrinter.cpp Thu Apr 2 02:02:51 2015
@@ -523,6 +523,7 @@ void X86AsmPrinter::EmitStartOfAsmFile(M
// must be registered in .sxdata. Use of any unregistered handlers will
// cause the process to terminate immediately. LLVM does not know how to
// register any SEH handlers, so its object files should be safe.
+ S->setAbsolute();
OutStreamer.EmitSymbolAttribute(S, MCSA_Global);
OutStreamer.EmitAssignment(
S, MCConstantExpr::Create(int64_t(1), MMI->getContext()));
Removed: llvm/trunk/test/MC/ELF/alias-resolve.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/alias-resolve.s?rev=233897&view=auto
==============================================================================
--- llvm/trunk/test/MC/ELF/alias-resolve.s (original)
+++ llvm/trunk/test/MC/ELF/alias-resolve.s (removed)
@@ -1,8 +0,0 @@
-// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -r | FileCheck %s
-
-a:
- .section foo
- c = b
-b:
- // CHECK: 0x0 R_X86_64_PC32 .text 0x0
- .long a - c
Modified: llvm/trunk/test/MC/ELF/alias.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/alias.s?rev=233898&r1=233897&r2=233898&view=diff
==============================================================================
--- llvm/trunk/test/MC/ELF/alias.s (original)
+++ llvm/trunk/test/MC/ELF/alias.s Thu Apr 2 02:02:51 2015
@@ -24,15 +24,6 @@ bar5 = bar4
bar6 = bar5
bar6:
-// Test that indirect local aliases do not appear as symbols.
-.data
-.Llocal:
-
-.text
-leaq .Llocal1(%rip), %rdi
-.Llocal1 = .Llocal2
-.Llocal2 = .Llocal
-
// CHECK: Symbols [
// CHECK-NEXT: Symbol {
// CHECK-NEXT: Name: (0)
Modified: llvm/trunk/test/MC/MachO/ARM/aliased-symbols.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/MachO/ARM/aliased-symbols.s?rev=233898&r1=233897&r2=233898&view=diff
==============================================================================
--- llvm/trunk/test/MC/MachO/ARM/aliased-symbols.s (original)
+++ llvm/trunk/test/MC/MachO/ARM/aliased-symbols.s Thu Apr 2 02:02:51 2015
@@ -45,9 +45,9 @@ Ltmp0:
// CHECK-NEXT: Value: 0x[[DEFINED_EARLY]]
// CHECK-NEXT: }
- // alias_to_late was an alias to defined_late. But we can resolve it.
+ // defined_late was defined. Just after defined_early.
// CHECK: Symbol {
-// CHECK-NEXT: Name: alias_to_late
+// CHECK-NEXT: Name: defined_late
// CHECK-NEXT: Type: Section (0xE)
// CHECK-NEXT: Section: __data (0x2)
// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
@@ -56,9 +56,9 @@ Ltmp0:
// CHECK-NEXT: Value: 0x[[DEFINED_LATE:[0-9A-F]+]]
// CHECK-NEXT: }
- // defined_late was defined. Just after defined_early.
+ // alias_to_late was an alias to defined_late. But we can resolve it.
// CHECK: Symbol {
-// CHECK-NEXT: Name: defined_late
+// CHECK-NEXT: Name: alias_to_late
// CHECK-NEXT: Type: Section (0xE)
// CHECK-NEXT: Section: __data (0x2)
// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
@@ -72,7 +72,7 @@ Ltmp0:
// CHECK: Symbol {
// CHECK-NEXT: Name: alias_to_local (42)
// CHECK-NEXT: Type: Section (0xE)
-// CHECK-NEXT: Section: __data (0x2)
+// CHECK-NEXT: Section: (0x0)
// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
// CHECK-NEXT: Flags [ (0x0)
// CHECK-NEXT: ]
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