Add the align_to_end option to .bundle_lock in the MC implementation of aligned
bundling. The document describing this feature and the implementation has also
been updated:
https://sites.google.com/a/chromium.org/dev/nativeclient/pnacl/aligned-bundling-support-in-llvm
llvm-svn: 171797
diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index 9b7074d..e234dfe 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -260,7 +260,7 @@
virtual void EmitInstruction(const MCInst &Inst);
virtual void EmitBundleAlignMode(unsigned AlignPow2);
- virtual void EmitBundleLock();
+ virtual void EmitBundleLock(bool AlignToEnd);
virtual void EmitBundleUnlock();
/// EmitRawText - If this file is backed by an assembly streamer, this dumps
@@ -1370,8 +1370,10 @@
EmitEOL();
}
-void MCAsmStreamer::EmitBundleLock() {
+void MCAsmStreamer::EmitBundleLock(bool AlignToEnd) {
OS << "\t.bundle_lock";
+ if (AlignToEnd)
+ OS << " align_to_end";
EmitEOL();
}
diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index 20b64e2..d30dc7d 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -167,10 +167,34 @@
"computeBundlePadding should only be called if bundling is enabled");
uint64_t BundleMask = BundleSize - 1;
uint64_t OffsetInBundle = FOffset & BundleMask;
+ uint64_t EndOfFragment = OffsetInBundle + FSize;
- // If the fragment would cross a bundle boundary, add enough padding until
- // the end of the current bundle.
- if (OffsetInBundle + FSize > BundleSize)
+ // There are two kinds of bundling restrictions:
+ //
+ // 1) For alignToBundleEnd(), add padding to ensure that the fragment will
+ // *end* on a bundle boundary.
+ // 2) Otherwise, check if the fragment would cross a bundle boundary. If it
+ // would, add padding until the end of the bundle so that the fragment
+ // will start in a new one.
+ if (F->alignToBundleEnd()) {
+ // Three possibilities here:
+ //
+ // A) The fragment just happens to end at a bundle boundary, so we're good.
+ // B) The fragment ends before the current bundle boundary: pad it just
+ // enough to reach the boundary.
+ // C) The fragment ends after the current bundle boundary: pad it until it
+ // reaches the end of the next bundle boundary.
+ //
+ // Note: this code could be made shorter with some modulo trickery, but it's
+ // intentionally kept in its more explicit form for simplicity.
+ if (EndOfFragment == BundleSize)
+ return 0;
+ else if (EndOfFragment < BundleSize)
+ return BundleSize - EndOfFragment;
+ else { // EndOfFragment > BundleSize
+ return 2 * BundleSize - EndOfFragment;
+ }
+ } else if (EndOfFragment > BundleSize)
return BundleSize - OffsetInBundle;
else
return 0;
@@ -204,7 +228,7 @@
: Section(&_Section),
Ordinal(~UINT32_C(0)),
Alignment(1),
- BundleLocked(false), BundleGroupBeforeFirstInst(false),
+ BundleLockState(NotBundleLocked), BundleGroupBeforeFirstInst(false),
HasInstructions(false)
{
if (A)
diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp
index e3acc44..e9afff6 100644
--- a/llvm/lib/MC/MCELFStreamer.cpp
+++ b/llvm/lib/MC/MCELFStreamer.cpp
@@ -379,8 +379,14 @@
MCSectionData *SD = getCurrentSectionData();
if (SD->isBundleLocked() && !SD->isBundleGroupBeforeFirstInst())
DF = getOrCreateDataFragment();
- else
+ else {
DF = new MCDataFragment(SD);
+ if (SD->getBundleLockState() == MCSectionData::BundleLockedAlignToEnd) {
+ // If this is a new fragment created for a bundle-locked group, and the
+ // group was marked as "align_to_end", set a flag in the fragment.
+ DF->setAlignToBundleEnd(true);
+ }
+ }
// We're now emitting an instruction in a bundle group, so this flag has
// to be turned off.
@@ -407,7 +413,7 @@
report_fatal_error(".bundle_align_mode should be only set once per file");
}
-void MCELFStreamer::EmitBundleLock() {
+void MCELFStreamer::EmitBundleLock(bool AlignToEnd) {
MCSectionData *SD = getCurrentSectionData();
// Sanity checks
@@ -417,7 +423,8 @@
else if (SD->isBundleLocked())
report_fatal_error("Nesting of .bundle_lock is forbidden");
- SD->setBundleLocked(true);
+ SD->setBundleLockState(AlignToEnd ? MCSectionData::BundleLockedAlignToEnd :
+ MCSectionData::BundleLocked);
SD->setBundleGroupBeforeFirstInst(true);
}
@@ -432,7 +439,7 @@
else if (SD->isBundleGroupBeforeFirstInst())
report_fatal_error("Empty bundle-locked group is forbidden");
- SD->setBundleLocked(false);
+ SD->setBundleLockState(MCSectionData::NotBundleLocked);
}
void MCELFStreamer::FinishImpl() {
diff --git a/llvm/lib/MC/MCNullStreamer.cpp b/llvm/lib/MC/MCNullStreamer.cpp
index d1cd006..364c324 100644
--- a/llvm/lib/MC/MCNullStreamer.cpp
+++ b/llvm/lib/MC/MCNullStreamer.cpp
@@ -96,7 +96,7 @@
virtual void EmitInstruction(const MCInst &Inst) {}
virtual void EmitBundleAlignMode(unsigned AlignPow2) {}
- virtual void EmitBundleLock() {}
+ virtual void EmitBundleLock(bool AlignToEnd) {}
virtual void EmitBundleUnlock() {}
virtual void FinishImpl() {}
diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 6d5c0a5..a848615 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -233,7 +233,7 @@
llvm_unreachable(BundlingNotImplementedMsg);
}
-void MCObjectStreamer::EmitBundleLock() {
+void MCObjectStreamer::EmitBundleLock(bool AlignToEnd) {
llvm_unreachable(BundlingNotImplementedMsg);
}
diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 8a22ed5..7c3fea5 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -2473,15 +2473,31 @@
}
/// ParseDirectiveBundleLock
-/// ::= {.bundle_lock}
+/// ::= {.bundle_lock} [align_to_end]
bool AsmParser::ParseDirectiveBundleLock() {
CheckForValidSection();
+ bool AlignToEnd = false;
- if (getLexer().isNot(AsmToken::EndOfStatement))
- return TokError("unexpected token in '.bundle_lock' directive");
+ if (getLexer().isNot(AsmToken::EndOfStatement)) {
+ StringRef Option;
+ SMLoc Loc = getTok().getLoc();
+ const char *kInvalidOptionError =
+ "invalid option for '.bundle_lock' directive";
+
+ if (ParseIdentifier(Option))
+ return Error(Loc, kInvalidOptionError);
+
+ if (Option != "align_to_end")
+ return Error(Loc, kInvalidOptionError);
+ else if (getLexer().isNot(AsmToken::EndOfStatement))
+ return Error(Loc,
+ "unexpected token after '.bundle_lock' directive option");
+ AlignToEnd = true;
+ }
+
Lex();
- getStreamer().EmitBundleLock();
+ getStreamer().EmitBundleLock(AlignToEnd);
return false;
}