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ARM: Diagnostics for out of range fixups.

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Replace some assert() calls w/ actual diagnostics. In a perfect world,
there'd be range checks on these values long before things ever reached
this code. For now, though, issuing a better-late-than-never diagnostic
is still a big improvement over assert().

rdar://11347287

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155851 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jim Grosbach 2012-04-30 22:30:43 +00:00
parent 887d095fb6
commit 7a3afa91ad
1 changed files with 52 additions and 34 deletions
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86
lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
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@ -12,6 +12,7 @@
#include "MCTargetDesc/ARMFixupKinds.h"
#include "MCTargetDesc/ARMAddressingModes.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCExpr.h"
@ -111,32 +112,7 @@ public:
void processFixupValue(const MCAssembler &Asm, const MCAsmLayout &Layout,
const MCFixup &Fixup, const MCFragment *DF,
MCValue &Target, uint64_t &Value,
bool &IsResolved) {
const MCSymbolRefExpr *A = Target.getSymA();
// Some fixups to thumb function symbols need the low bit (thumb bit)
// twiddled.
if ((unsigned)Fixup.getKind() != ARM::fixup_arm_ldst_pcrel_12 &&
(unsigned)Fixup.getKind() != ARM::fixup_t2_ldst_pcrel_12 &&
(unsigned)Fixup.getKind() != ARM::fixup_arm_adr_pcrel_12 &&
(unsigned)Fixup.getKind() != ARM::fixup_thumb_adr_pcrel_10 &&
(unsigned)Fixup.getKind() != ARM::fixup_t2_adr_pcrel_12 &&
(unsigned)Fixup.getKind() != ARM::fixup_arm_thumb_cp) {
if (A) {
const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
if (Asm.isThumbFunc(&Sym))
Value |= 1;
}
}
// We must always generate a relocation for BL/BLX instructions if we have
// a symbol to reference, as the linker relies on knowing the destination
// symbol's thumb-ness to get interworking right.
if (A && ((unsigned)Fixup.getKind() == ARM::fixup_arm_thumb_blx ||
(unsigned)Fixup.getKind() == ARM::fixup_arm_thumb_bl ||
(unsigned)Fixup.getKind() == ARM::fixup_arm_blx ||
(unsigned)Fixup.getKind() == ARM::fixup_arm_uncondbl ||
(unsigned)Fixup.getKind() == ARM::fixup_arm_condbl))
IsResolved = false;
}
bool &IsResolved);
bool mayNeedRelaxation(const MCInst &Inst) const;
@ -270,7 +246,9 @@ bool ARMAsmBackend::writeNopData(uint64_t Count, MCObjectWriter *OW) const {
return true;
}
static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
MCContext *Ctx = NULL) {
unsigned Kind = Fixup.getKind();
switch (Kind) {
default:
llvm_unreachable("Unknown fixup kind!");
@ -323,7 +301,8 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
Value = -Value;
isAdd = false;
}
assert ((Value < 4096) && "Out of range pc-relative fixup value!");
if (Ctx && Value >= 4096)
Ctx->FatalError(Fixup.getLoc(), "out of range pc-relative fixup value");
Value |= isAdd << 23;
// Same addressing mode as fixup_arm_pcrel_10,
@ -346,8 +325,8 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
Value = -Value;
opc = 2; // 0b0010
}
assert(ARM_AM::getSOImmVal(Value) != -1 &&
"Out of range pc-relative fixup value!");
if (Ctx && ARM_AM::getSOImmVal(Value) == -1)
Ctx->FatalError(Fixup.getLoc(), "out of range pc-relative fixup value");
// Encode the immediate and shift the opcode into place.
return ARM_AM::getSOImmVal(Value) | (opc << 21);
}
@ -474,7 +453,8 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
isAdd = false;
}
// The value has the low 4 bits encoded in [3:0] and the high 4 in [11:8].
assert ((Value < 256) && "Out of range pc-relative fixup value!");
if (Ctx && Value >= 256)
Ctx->FatalError(Fixup.getLoc(), "out of range pc-relative fixup value");
Value = (Value & 0xf) | ((Value & 0xf0) << 4);
return Value | (isAdd << 23);
}
@ -492,7 +472,8 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
}
// These values don't encode the low two bits since they're always zero.
Value >>= 2;
assert ((Value < 256) && "Out of range pc-relative fixup value!");
if (Ctx && Value >= 256)
Ctx->FatalError(Fixup.getLoc(), "out of range pc-relative fixup value");
Value |= isAdd << 23;
// Same addressing mode as fixup_arm_pcrel_10, but with 16-bit halfwords
@ -508,6 +489,43 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
}
}
void ARMAsmBackend::processFixupValue(const MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFixup &Fixup,
const MCFragment *DF,
MCValue &Target, uint64_t &Value,
bool &IsResolved) {
const MCSymbolRefExpr *A = Target.getSymA();
// Some fixups to thumb function symbols need the low bit (thumb bit)
// twiddled.
if ((unsigned)Fixup.getKind() != ARM::fixup_arm_ldst_pcrel_12 &&
(unsigned)Fixup.getKind() != ARM::fixup_t2_ldst_pcrel_12 &&
(unsigned)Fixup.getKind() != ARM::fixup_arm_adr_pcrel_12 &&
(unsigned)Fixup.getKind() != ARM::fixup_thumb_adr_pcrel_10 &&
(unsigned)Fixup.getKind() != ARM::fixup_t2_adr_pcrel_12 &&
(unsigned)Fixup.getKind() != ARM::fixup_arm_thumb_cp) {
if (A) {
const MCSymbol &Sym = A->getSymbol().AliasedSymbol();
if (Asm.isThumbFunc(&Sym))
Value |= 1;
}
}
// We must always generate a relocation for BL/BLX instructions if we have
// a symbol to reference, as the linker relies on knowing the destination
// symbol's thumb-ness to get interworking right.
if (A && ((unsigned)Fixup.getKind() == ARM::fixup_arm_thumb_blx ||
(unsigned)Fixup.getKind() == ARM::fixup_arm_thumb_bl ||
(unsigned)Fixup.getKind() == ARM::fixup_arm_blx ||
(unsigned)Fixup.getKind() == ARM::fixup_arm_uncondbl ||
(unsigned)Fixup.getKind() == ARM::fixup_arm_condbl))
IsResolved = false;
// Try to get the encoded value for the fixup as-if we're mapping it into
// the instruction. This allows adjustFixupValue() to issue a diagnostic
// if the value aren't invalid.
(void)adjustFixupValue(Fixup, Value, &Asm.getContext());
}
namespace {
// FIXME: This should be in a separate file.
@ -531,7 +549,7 @@ public:
void ELFARMAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
unsigned DataSize, uint64_t Value) const {
unsigned NumBytes = 4; // FIXME: 2 for Thumb
Value = adjustFixupValue(Fixup.getKind(), Value);
Value = adjustFixupValue(Fixup, Value);
if (!Value) return; // Doesn't change encoding.
unsigned Offset = Fixup.getOffset();
@ -616,7 +634,7 @@ static unsigned getFixupKindNumBytes(unsigned Kind) {
void DarwinARMAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
unsigned DataSize, uint64_t Value) const {
unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind());
Value = adjustFixupValue(Fixup.getKind(), Value);
Value = adjustFixupValue(Fixup, Value);
if (!Value) return; // Doesn't change encoding.
unsigned Offset = Fixup.getOffset();