[llvm] [lldb] [clang] [BOLT] Extend calculateEmittedSize for Block Size Calculation (PR #73076)
via cfe-commits
cfe-commits at lists.llvm.org
Wed Nov 22 08:54:19 PST 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-driver
@llvm/pr-subscribers-mc
@llvm/pr-subscribers-lldb
Author: ShatianWang (ShatianWang)
<details>
<summary>Changes</summary>
This commit modifies BinaryContext::calculateEmittedSize to update the BinaryBasicBlock::OutputAddressRange for each basic block in the input BF. The modification is done in place, where BB.OutputAddressRange.second less BB.OutputAddressRange.first now gives the emitted size of the basic block.
---
Patch is 31.51 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/73076.diff
21 Files Affected:
- (modified) bolt/include/bolt/Core/BinaryContext.h (+3)
- (modified) bolt/lib/Core/BinaryContext.cpp (+29-6)
- (modified) bolt/lib/Core/BinaryEmitter.cpp (+1)
- (modified) clang/include/clang/Driver/Options.td (+4)
- (modified) clang/lib/Driver/ToolChains/Gnu.cpp (+29)
- (modified) cross-project-tests/lit.cfg.py (+13-1)
- (modified) cross-project-tests/lit.site.cfg.py.in (+4)
- (modified) lldb/test/API/lit.cfg.py (+5)
- (modified) lldb/test/API/lit.site.cfg.py.in (+8)
- (modified) lldb/test/Shell/helper/toolchain.py (+5)
- (modified) lldb/test/Shell/lit.site.cfg.py.in (+9)
- (modified) llvm/CMakeLists.txt (+4)
- (modified) llvm/include/llvm/MC/MCFragment.h (+22)
- (modified) llvm/include/llvm/MC/MCObjectStreamer.h (+2)
- (modified) llvm/include/llvm/MC/MCStreamer.h (+6)
- (modified) llvm/lib/MC/MCAssembler.cpp (+81-37)
- (modified) llvm/lib/MC/MCFragment.cpp (+12)
- (modified) llvm/lib/MC/MCObjectStreamer.cpp (+5)
- (modified) llvm/lib/MC/MCStreamer.cpp (+2)
- (modified) llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp (+24)
- (added) llvm/test/MC/X86/directive-avoid_end_align.s (+208)
``````````diff
diff --git a/bolt/include/bolt/Core/BinaryContext.h b/bolt/include/bolt/Core/BinaryContext.h
index a4e84cb93c093dc2..258063e8584bb5d2 100644
--- a/bolt/include/bolt/Core/BinaryContext.h
+++ b/bolt/include/bolt/Core/BinaryContext.h
@@ -1230,6 +1230,9 @@ class BinaryContext {
///
/// Return the pair where the first size is for the main part, and the second
/// size is for the cold one.
+ /// Modify BinaryBasicBlock::OutputAddressRange for each basic block in the
+ /// function in place so that BB.OutputAddressRange.second less
+ /// BB.OutputAddressRange.first gives the emitted size of BB.
std::pair<size_t, size_t> calculateEmittedSize(BinaryFunction &BF,
bool FixBranches = true);
diff --git a/bolt/lib/Core/BinaryContext.cpp b/bolt/lib/Core/BinaryContext.cpp
index cd70bdb7a4228d0b..af33398c9a9f2736 100644
--- a/bolt/lib/Core/BinaryContext.cpp
+++ b/bolt/lib/Core/BinaryContext.cpp
@@ -2322,14 +2322,37 @@ BinaryContext::calculateEmittedSize(BinaryFunction &BF, bool FixBranches) {
MCAsmLayout Layout(Assembler);
Assembler.layout(Layout);
+ // Obtain fragment sizes.
+ std::vector<uint64_t> FragmentSizes;
+ // Main fragment size.
const uint64_t HotSize =
Layout.getSymbolOffset(*EndLabel) - Layout.getSymbolOffset(*StartLabel);
- const uint64_t ColdSize =
- std::accumulate(SplitLabels.begin(), SplitLabels.end(), 0ULL,
- [&](const uint64_t Accu, const LabelRange &Labels) {
- return Accu + Layout.getSymbolOffset(*Labels.second) -
- Layout.getSymbolOffset(*Labels.first);
- });
+ FragmentSizes.push_back(HotSize);
+ // Split fragment sizes.
+ uint64_t ColdSize = 0;
+ for (const auto &Labels : SplitLabels) {
+ uint64_t Size = Layout.getSymbolOffset(*Labels.second) -
+ Layout.getSymbolOffset(*Labels.first);
+ FragmentSizes.push_back(Size);
+ ColdSize += Size;
+ }
+
+ // Populate new start and end offsets of each basic block.
+ BinaryBasicBlock *PrevBB = nullptr;
+ uint64_t FragmentIndex = 0;
+ for (FunctionFragment &FF : BF.getLayout().fragments()) {
+ for (BinaryBasicBlock *BB : FF) {
+ const uint64_t BBStartOffset = Layout.getSymbolOffset(*(BB->getLabel()));
+ BB->setOutputStartAddress(BBStartOffset);
+ if (PrevBB)
+ PrevBB->setOutputEndAddress(BBStartOffset);
+ PrevBB = BB;
+ }
+ if (PrevBB)
+ PrevBB->setOutputEndAddress(FragmentSizes[FragmentIndex]);
+ FragmentIndex++;
+ PrevBB = nullptr;
+ }
// Clean-up the effect of the code emission.
for (const MCSymbol &Symbol : Assembler.symbols()) {
diff --git a/bolt/lib/Core/BinaryEmitter.cpp b/bolt/lib/Core/BinaryEmitter.cpp
index fb1bf530c1974aa2..82fbd8c0f67b215f 100644
--- a/bolt/lib/Core/BinaryEmitter.cpp
+++ b/bolt/lib/Core/BinaryEmitter.cpp
@@ -482,6 +482,7 @@ void BinaryEmitter::emitFunctionBody(BinaryFunction &BF, FunctionFragment &FF,
// This assumes the second instruction in the macro-op pair will get
// assigned to its own MCRelaxableFragment. Since all JCC instructions
// are relaxable, we should be safe.
+ Streamer.emitNeverAlignCodeAtEnd(/*Alignment to avoid=*/64, *BC.STI);
}
if (!EmitCodeOnly) {
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index b2f2bcb6ac379109..c1a06aab30534fd4 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -5199,6 +5199,10 @@ def pg : Flag<["-"], "pg">, HelpText<"Enable mcount instrumentation">,
MarshallingInfoFlag<CodeGenOpts<"InstrumentForProfiling">>;
def pipe : Flag<["-", "--"], "pipe">,
HelpText<"Use pipes between commands, when possible">;
+// Facebook T92898286
+def post_link_optimize : Flag<["--"], "post-link-optimize">,
+ HelpText<"Apply post-link optimizations using BOLT">;
+// End Facebook T92898286
def prebind__all__twolevel__modules : Flag<["-"], "prebind_all_twolevel_modules">;
def prebind : Flag<["-"], "prebind">;
def preload : Flag<["-"], "preload">;
diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index 2b1e8f02cf663885..07f2d90c82386497 100644
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -662,12 +662,41 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
}
}
+ // Facebook T92898286
+ if (Args.hasArg(options::OPT_post_link_optimize))
+ CmdArgs.push_back("-q");
+ // End Facebook T92898286
+
Args.AddAllArgs(CmdArgs, options::OPT_T);
const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
C.addCommand(std::make_unique<Command>(JA, *this,
ResponseFileSupport::AtFileCurCP(),
Exec, CmdArgs, Inputs, Output));
+ // Facebook T92898286
+ if (!Args.hasArg(options::OPT_post_link_optimize) || !Output.isFilename())
+ return;
+
+ const char *MvExec = Args.MakeArgString(ToolChain.GetProgramPath("mv"));
+ ArgStringList MoveCmdArgs;
+ MoveCmdArgs.push_back(Output.getFilename());
+ const char *PreBoltBin =
+ Args.MakeArgString(Twine(Output.getFilename()) + ".pre-bolt");
+ MoveCmdArgs.push_back(PreBoltBin);
+ C.addCommand(std::make_unique<Command>(JA, *this, ResponseFileSupport::None(),
+ MvExec, MoveCmdArgs, std::nullopt));
+
+ ArgStringList BoltCmdArgs;
+ const char *BoltExec =
+ Args.MakeArgString(ToolChain.GetProgramPath("llvm-bolt"));
+ BoltCmdArgs.push_back(PreBoltBin);
+ BoltCmdArgs.push_back("-reorder-blocks=reverse");
+ BoltCmdArgs.push_back("-update-debug-sections");
+ BoltCmdArgs.push_back("-o");
+ BoltCmdArgs.push_back(Output.getFilename());
+ C.addCommand(std::make_unique<Command>(JA, *this, ResponseFileSupport::None(),
+ BoltExec, BoltCmdArgs, std::nullopt));
+ // End Facebook T92898286
}
void tools::gnutools::Assembler::ConstructJob(Compilation &C,
diff --git a/cross-project-tests/lit.cfg.py b/cross-project-tests/lit.cfg.py
index 774c4eaf4d976b26..619634578dfe609a 100644
--- a/cross-project-tests/lit.cfg.py
+++ b/cross-project-tests/lit.cfg.py
@@ -84,7 +84,13 @@ def get_required_attr(config, attr_name):
# use_clang() and use_lld() respectively, so set them to "", if needed.
if not hasattr(config, "clang_src_dir"):
config.clang_src_dir = ""
-llvm_config.use_clang(required=("clang" in config.llvm_enabled_projects))
+# Facebook T92898286
+should_test_bolt = get_required_attr(config, "llvm_test_bolt")
+if should_test_bolt:
+ llvm_config.use_clang(required=("clang" in config.llvm_enabled_projects), additional_flags=["--post-link-optimize"])
+else:
+ llvm_config.use_clang(required=("clang" in config.llvm_enabled_projects))
+# End Facebook T92898286
if not hasattr(config, "lld_src_dir"):
config.lld_src_dir = ""
@@ -293,3 +299,9 @@ def get_clang_default_dwarf_version_string(triple):
# Allow 'REQUIRES: XXX-registered-target' in tests.
for arch in config.targets_to_build:
config.available_features.add(arch.lower() + "-registered-target")
+
+# Facebook T92898286
+# Ensure the user's PYTHONPATH is included.
+if "PYTHONPATH" in os.environ:
+ config.environment["PYTHONPATH"] = os.environ["PYTHONPATH"]
+# End Facebook T92898286
diff --git a/cross-project-tests/lit.site.cfg.py.in b/cross-project-tests/lit.site.cfg.py.in
index 39458dfc79afd2ad..2d53cd377f0330de 100644
--- a/cross-project-tests/lit.site.cfg.py.in
+++ b/cross-project-tests/lit.site.cfg.py.in
@@ -21,6 +21,10 @@ config.mlir_src_root = "@MLIR_SOURCE_DIR@"
config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"
+# Facebook T92898286
+config.llvm_test_bolt = lit.util.pythonize_bool("@LLVM_TEST_BOLT@")
+# End Facebook T92898286
+
import lit.llvm
lit.llvm.initialize(lit_config, config)
diff --git a/lldb/test/API/lit.cfg.py b/lldb/test/API/lit.cfg.py
index 8b35e8b2a217cf7c..3c0c6baa6f55d8a5 100644
--- a/lldb/test/API/lit.cfg.py
+++ b/lldb/test/API/lit.cfg.py
@@ -244,6 +244,11 @@ def delete_module_cache(path):
if is_configured("lldb_framework_dir"):
dotest_cmd += ["--framework", config.lldb_framework_dir]
+# Facebook T92898286
+if is_configured("llvm_test_bolt"):
+ dotest_cmd += ["-E", '"--post-link-optimize"']
+# End Facebook T92898286
+
if (
"lldb-repro-capture" in config.available_features
or "lldb-repro-replay" in config.available_features
diff --git a/lldb/test/API/lit.site.cfg.py.in b/lldb/test/API/lit.site.cfg.py.in
index 053331dc4881f77c..1da91d8fb5508ce9 100644
--- a/lldb/test/API/lit.site.cfg.py.in
+++ b/lldb/test/API/lit.site.cfg.py.in
@@ -1,5 +1,9 @@
@LIT_SITE_CFG_IN_HEADER@
+#Facebook T92898286
+import lit.util
+#End Facebook T92898286
+
config.llvm_src_root = "@LLVM_SOURCE_DIR@"
config.llvm_obj_root = "@LLVM_BINARY_DIR@"
config.llvm_tools_dir = lit_config.substitute("@LLVM_TOOLS_DIR@")
@@ -39,6 +43,10 @@ config.libcxx_include_target_dir = "@LIBCXX_GENERATED_INCLUDE_TARGET_DIR@"
config.lldb_module_cache = os.path.join("@LLDB_TEST_MODULE_CACHE_LLDB@", "lldb-api")
config.clang_module_cache = os.path.join("@LLDB_TEST_MODULE_CACHE_CLANG@", "lldb-api")
+# Facebook T92898286
+config.llvm_test_bolt = lit.util.pythonize_bool("@LLVM_TEST_BOLT@")
+# End Facebook T92898286
+
# Plugins
lldb_build_intel_pt = '@LLDB_BUILD_INTEL_PT@'
if lldb_build_intel_pt == '1':
diff --git a/lldb/test/Shell/helper/toolchain.py b/lldb/test/Shell/helper/toolchain.py
index 255955fc70d8c417..7b7be06643166dfb 100644
--- a/lldb/test/Shell/helper/toolchain.py
+++ b/lldb/test/Shell/helper/toolchain.py
@@ -165,6 +165,11 @@ def use_support_substitutions(config):
if config.cmake_sysroot:
host_flags += ["--sysroot={}".format(config.cmake_sysroot)]
+ # Facebook T92898286
+ if config.llvm_test_bolt:
+ host_flags += ["--post-link-optimize"]
+ # End Facebook T92898286
+
host_flags = " ".join(host_flags)
config.substitutions.append(("%clang_host", "%clang " + host_flags))
config.substitutions.append(("%clangxx_host", "%clangxx " + host_flags))
diff --git a/lldb/test/Shell/lit.site.cfg.py.in b/lldb/test/Shell/lit.site.cfg.py.in
index 736dfc335732b5af..3b4d99aa076a4556 100644
--- a/lldb/test/Shell/lit.site.cfg.py.in
+++ b/lldb/test/Shell/lit.site.cfg.py.in
@@ -1,5 +1,10 @@
@LIT_SITE_CFG_IN_HEADER@
+#Facebook T92898286
+import lit.util
+#End Facebook T92898286
+
+
config.llvm_src_root = "@LLVM_SOURCE_DIR@"
config.llvm_obj_root = "@LLVM_BINARY_DIR@"
config.llvm_tools_dir = lit_config.substitute("@LLVM_TOOLS_DIR@")
@@ -30,6 +35,10 @@ config.lldb_system_debugserver = @LLDB_USE_SYSTEM_DEBUGSERVER@
config.lldb_module_cache = os.path.join("@LLDB_TEST_MODULE_CACHE_LLDB@", "lldb-shell")
config.clang_module_cache = os.path.join("@LLDB_TEST_MODULE_CACHE_CLANG@", "lldb-shell")
+# Facebook T92898286
+config.llvm_test_bolt = lit.util.pythonize_bool("@LLVM_TEST_BOLT@")
+# End Facebook T92898286
+
import lit.llvm
lit.llvm.initialize(lit_config, config)
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index 1c983165b2ef0039..cba26c7a617fa4ae 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -685,6 +685,10 @@ set(LLVM_LIB_FUZZING_ENGINE "" CACHE PATH
option(LLVM_USE_SPLIT_DWARF
"Use -gsplit-dwarf when compiling llvm and --gdb-index when linking." OFF)
+# Facebook T92898286
+option(LLVM_TEST_BOLT "Enable BOLT testing in non-BOLT tests that use clang" OFF)
+# End Facebook T92898286
+
# Define an option controlling whether we should build for 32-bit on 64-bit
# platforms, where supported.
if( CMAKE_SIZEOF_VOID_P EQUAL 8 AND NOT (WIN32 OR ${CMAKE_SYSTEM_NAME} MATCHES "AIX"))
diff --git a/llvm/include/llvm/MC/MCFragment.h b/llvm/include/llvm/MC/MCFragment.h
index c314fdd3aa69730d..806ba0dc5fe28b49 100644
--- a/llvm/include/llvm/MC/MCFragment.h
+++ b/llvm/include/llvm/MC/MCFragment.h
@@ -33,6 +33,7 @@ class MCFragment : public ilist_node_with_parent<MCFragment, MCSection> {
public:
enum FragmentType : uint8_t {
FT_Align,
+ FT_NeverAlign,
FT_Data,
FT_CompactEncodedInst,
FT_Fill,
@@ -344,6 +345,27 @@ class MCAlignFragment : public MCFragment {
}
};
+class MCNeverAlignFragment : public MCFragment {
+ /// The alignment the end of the next fragment should avoid.
+ unsigned Alignment;
+
+ /// When emitting Nops some subtargets have specific nop encodings.
+ const MCSubtargetInfo &STI;
+
+public:
+ MCNeverAlignFragment(unsigned Alignment, const MCSubtargetInfo &STI,
+ MCSection *Sec = nullptr)
+ : MCFragment(FT_NeverAlign, false, Sec), Alignment(Alignment), STI(STI) {}
+
+ unsigned getAlignment() const { return Alignment; }
+
+ const MCSubtargetInfo &getSubtargetInfo() const { return STI; }
+
+ static bool classof(const MCFragment *F) {
+ return F->getKind() == MCFragment::FT_NeverAlign;
+ }
+};
+
class MCFillFragment : public MCFragment {
uint8_t ValueSize;
/// Value to use for filling bytes.
diff --git a/llvm/include/llvm/MC/MCObjectStreamer.h b/llvm/include/llvm/MC/MCObjectStreamer.h
index 5e5b4b3150170954..3c6fd9301647db7c 100644
--- a/llvm/include/llvm/MC/MCObjectStreamer.h
+++ b/llvm/include/llvm/MC/MCObjectStreamer.h
@@ -157,6 +157,8 @@ class MCObjectStreamer : public MCStreamer {
unsigned MaxBytesToEmit = 0) override;
void emitCodeAlignment(Align ByteAlignment, const MCSubtargetInfo *STI,
unsigned MaxBytesToEmit = 0) override;
+ void emitNeverAlignCodeAtEnd(unsigned ByteAlignment,
+ const MCSubtargetInfo &STI) override;
void emitValueToOffset(const MCExpr *Offset, unsigned char Value,
SMLoc Loc) override;
void emitDwarfLocDirective(unsigned FileNo, unsigned Line, unsigned Column,
diff --git a/llvm/include/llvm/MC/MCStreamer.h b/llvm/include/llvm/MC/MCStreamer.h
index 3bf2d22e182353ff..87691a6ec0e08dd8 100644
--- a/llvm/include/llvm/MC/MCStreamer.h
+++ b/llvm/include/llvm/MC/MCStreamer.h
@@ -885,6 +885,12 @@ class MCStreamer {
virtual void emitCodeAlignment(Align Alignment, const MCSubtargetInfo *STI,
unsigned MaxBytesToEmit = 0);
+ /// If the end of the fragment following this NeverAlign fragment ever gets
+ /// aligned to \p ByteAlignment, this fragment emits a single nop before the
+ /// following fragment to break this end-alignment.
+ virtual void emitNeverAlignCodeAtEnd(unsigned ByteAlignment,
+ const MCSubtargetInfo &STI);
+
/// Emit some number of copies of \p Value until the byte offset \p
/// Offset is reached.
///
diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index 901a66f156663f83..15c8b016fef6094a 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -297,6 +297,43 @@ bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
return IsResolved;
}
+/// Check if the branch crosses the boundary.
+///
+/// \param StartAddr start address of the fused/unfused branch.
+/// \param Size size of the fused/unfused branch.
+/// \param BoundaryAlignment alignment requirement of the branch.
+/// \returns true if the branch cross the boundary.
+static bool mayCrossBoundary(uint64_t StartAddr, uint64_t Size,
+ Align BoundaryAlignment) {
+ uint64_t EndAddr = StartAddr + Size;
+ return (StartAddr >> Log2(BoundaryAlignment)) !=
+ ((EndAddr - 1) >> Log2(BoundaryAlignment));
+}
+
+/// Check if the branch is against the boundary.
+///
+/// \param StartAddr start address of the fused/unfused branch.
+/// \param Size size of the fused/unfused branch.
+/// \param BoundaryAlignment alignment requirement of the branch.
+/// \returns true if the branch is against the boundary.
+static bool isAgainstBoundary(uint64_t StartAddr, uint64_t Size,
+ Align BoundaryAlignment) {
+ uint64_t EndAddr = StartAddr + Size;
+ return (EndAddr & (BoundaryAlignment.value() - 1)) == 0;
+}
+
+/// Check if the branch needs padding.
+///
+/// \param StartAddr start address of the fused/unfused branch.
+/// \param Size size of the fused/unfused branch.
+/// \param BoundaryAlignment alignment requirement of the branch.
+/// \returns true if the branch needs padding.
+static bool needPadding(uint64_t StartAddr, uint64_t Size,
+ Align BoundaryAlignment) {
+ return mayCrossBoundary(StartAddr, Size, BoundaryAlignment) ||
+ isAgainstBoundary(StartAddr, Size, BoundaryAlignment);
+}
+
uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
const MCFragment &F) const {
assert(getBackendPtr() && "Requires assembler backend");
@@ -357,6 +394,41 @@ uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
return Size;
}
+ case MCFragment::FT_NeverAlign: {
+ // Disclaimer: NeverAlign fragment size depends on the size of its immediate
+ // successor, but NeverAlign need not be a MCRelaxableFragment.
+ // NeverAlign fragment size is recomputed if the successor is relaxed:
+ // - If RelaxableFragment is relaxed, it gets invalidated by marking its
+ // predecessor as LastValidFragment.
+ // - This forces the assembler to call MCAsmLayout::layoutFragment on that
+ // relaxable fragment, which in turn will always ask the predecessor to
+ // compute its size (see "computeFragmentSize(prev)" in layoutFragment).
+ //
+ // In short, the simplest way to ensure that computeFragmentSize() is sane
+ // is to establish the following rule: it should never examine fragments
+ // after the current fragment in the section. If we logically need to
+ // examine any fragment after the current fragment, we need to do that using
+ // relaxation, inside MCAssembler::layoutSectionOnce.
+ const MCNeverAlignFragment &NAF = cast<MCNeverAlignFragment>(F);
+ const MCFragment *NF = F.getNextNode();
+ uint64_t Offset = Layout.getFragmentOffset(&NAF);
+ size_t NextFragSize = 0;
+ if (const auto *NextFrag = dyn_cast<MCRelaxableFragment>(NF)) {
+ NextFragSize = NextFrag->getContents().size();
+ } else if (const auto *NextFrag = dyn_cast<MCDataFragment>(NF)) {
+ NextFragSize = NextFrag->getContents().size();
+ } else {
+ llvm_unreachable("Didn't find the expected fragment after NeverAlign");
+ }
+ // Check if the next fragment ends at the alignment we want to avoid.
+ if (isAgainstBoundary(Offset, NextFragSize, Align(NAF.getAlignment()))) {
+ // Avoid this alignment by introducing minimum nop.
+ assert(getBackend().getMinimumNopSize() != NAF.getAlignment());
+ return getBackend().getMinimumNopSize();
+ }
+ return 0;
+ }
+
case MCFragment::FT_Org: {
const MCOrgFragment &OF = cast<MCOrgFragment>(F);
MCValue Value;
@@ -580,6 +652,15 @@ static void writeFragment(raw_ostream &OS, const MCAssembler &Asm,
break;
}
+ case MCFragment::FT_NeverAlign: {
+ const MCNeverAlignFragment &NAF = cast<MCNeverAlignFragment>(F);
+ if (!Asm.getBackend().writeNopData(OS, FragmentSize,
+ &NAF.getSubtargetInfo()))
+ report_fatal_error("unable to write nop sequence of " +
+ Twine(FragmentSize) + " bytes");
+ break;
+ }
+
case MCFragment::FT_Data:
++stats::EmittedDataFragments;
OS << cast<MCDataFragment>(F).getContents();
@@ -1046,43 +1127,6 @@ bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
return OldSize != LF.getContents().size();
}
-/// Check if the branch crosses the boundary.
-///
-/// \param StartAddr start address of the fused/unfused branch.
-/// \param Size size of the fused/unfused branch.
-/// \param BoundaryAlignment alignment requirement of the branch.
-/// \returns true if the branch cross the boundary.
-static bool mayCrossBoundary(uint64_t StartAddr, uint64_t Size,
- Align BoundaryAlignment) {
- uint64_t EndAddr = StartAddr + Size;
- return (StartAddr >> Log2(BoundaryAlignment)) !=
- ((EndAddr - 1) >> Log2(BoundaryAlignment));
-}
-
-/// Check if the branch is against the boundary.
-///
-/// \param StartAddr start address of the fused/unfused branch.
-/// \param Size size of the fused/unfused branch.
...
[truncated]
``````````
</details>
https://github.com/llvm/llvm-project/pull/73076
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