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Add a -ignore-always-inline frontend flag which ignores @inline(__always) attributes. (#33466)
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6 files changed

+99
-7
lines changed

6 files changed

+99
-7
lines changed

‎include/swift/AST/SILOptions.h‎

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Original file line numberDiff line numberDiff line change
@@ -128,6 +128,11 @@ class SILOptions {
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/// Assume that code will be executed in a single-threaded environment.
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bool AssumeSingleThreaded = false;
130130

131+
/// Turn @inline(__always) attributes into no-ops.
132+
///
133+
/// For experimentation around code size reduction.
134+
bool IgnoreAlwaysInline = false;
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131136
/// Indicates which sanitizer is turned on.
132137
OptionSet<SanitizerKind> Sanitizers;
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‎include/swift/Option/FrontendOptions.td‎

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@@ -601,6 +601,9 @@ def disable_incremental_llvm_codegeneration :
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Flag<["-"], "disable-incremental-llvm-codegen">,
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HelpText<"Disable incremental llvm code generation.">;
603603

604+
def ignore_always_inline : Flag<["-"], "ignore-always-inline">,
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HelpText<"Ignore @inline(__always) attributes.">;
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604607
def emit_sorted_sil : Flag<["-"], "emit-sorted-sil">,
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HelpText<"When printing SIL, print out all sil entities sorted by name to "
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"ease diffing">;

‎lib/Frontend/CompilerInvocation.cpp‎

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@@ -1128,6 +1128,8 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
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Opts.AssumeSingleThreaded = true;
11291129
}
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1131+
Opts.IgnoreAlwaysInline |= Args.hasArg(OPT_ignore_always_inline);
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// Parse the assert configuration identifier.
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if (const Arg *A = Args.getLastArg(OPT_AssertConfig)) {
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StringRef Configuration = A->getValue();

‎lib/SILOptimizer/Transforms/PerformanceInliner.cpp‎

Lines changed: 12 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -559,6 +559,15 @@ static bool returnsClosure(SILFunction *F) {
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return false;
560560
}
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562+
static bool isInlineAlwaysCallSite(SILFunction *Callee) {
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if (Callee->isTransparent())
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return true;
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if (Callee->getInlineStrategy() == AlwaysInline)
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if (!Callee->getModule().getOptions().IgnoreAlwaysInline)
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return true;
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return false;
569+
}
570+
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/// Checks if a given generic apply should be inlined unconditionally, i.e.
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/// without any complex analysis using e.g. a cost model.
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/// It returns true if a function should be inlined.
@@ -585,7 +594,7 @@ static Optional<bool> shouldInlineGeneric(FullApplySite AI) {
585594

586595
// Always inline generic functions which are marked as
587596
// AlwaysInline or transparent.
588-
if (Callee->getInlineStrategy() == AlwaysInline || Callee->isTransparent())
597+
if (isInlineAlwaysCallSite(Callee))
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return true;
590599

591600
// If all substitutions are concrete, then there is no need to perform the
@@ -632,7 +641,7 @@ bool SILPerformanceInliner::decideInWarmBlock(
632641

633642
SILFunction *Callee = AI.getReferencedFunctionOrNull();
634643

635-
if (Callee->getInlineStrategy() == AlwaysInline || Callee->isTransparent()) {
644+
if (isInlineAlwaysCallSite(Callee)) {
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LLVM_DEBUG(dumpCaller(AI.getFunction());
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llvm::dbgs() << " always-inline decision "
638647
<< Callee->getName() << '\n');
@@ -655,7 +664,7 @@ bool SILPerformanceInliner::decideInColdBlock(FullApplySite AI,
655664
return false;
656665
}
657666

658-
if (Callee->getInlineStrategy() == AlwaysInline || Callee->isTransparent()) {
667+
if (isInlineAlwaysCallSite(Callee)) {
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LLVM_DEBUG(dumpCaller(AI.getFunction());
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llvm::dbgs() << " always-inline decision "
661670
<< Callee->getName() << '\n');
@@ -717,10 +726,6 @@ addToBBCounts(llvm::DenseMap<SILBasicBlock *, uint64_t> &BBToWeightMap,
717726
}
718727
}
719728

720-
static bool isInlineAlwaysCallSite(SILFunction *Callee) {
721-
return Callee->getInlineStrategy() == AlwaysInline || Callee->isTransparent();
722-
}
723-
724729
static void
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calculateBBWeights(SILFunction *Caller, DominanceInfo *DT,
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llvm::DenseMap<SILBasicBlock *, uint64_t> &BBToWeightMap) {

‎test/SILOptimizer/ignore-always-inline.sil‎

Lines changed: 71 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,71 @@
1+
// RUN: %target-sil-opt -enable-sil-verify-all %s -inline -dce | %FileCheck %s -check-prefix=REGULAR
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// RUN: %target-sil-opt -enable-sil-verify-all %s -inline -dce -ignore-always-inline | %FileCheck %s -check-prefix=IGNORED
3+
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sil_stage canonical
5+
6+
// REGULAR: sil [Osize] @caller
7+
// IGNORED: sil [Osize] @caller
8+
sil [Osize] @caller : $@convention(thin) () -> () {
9+
bb0:
10+
// REGULAR-NOT: function_ref @callee
11+
// REGULAR: function_ref @foobar
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// IGNORED: function_ref @callee
13+
%d1 = function_ref @callee : $@convention(thin) () -> ()
14+
apply %d1() : $@convention(thin) () -> ()
15+
16+
%9999 = tuple()
17+
return %9999 : $()
18+
}
19+
20+
sil @foobar : $@convention(thin) () -> ()
21+
22+
// callee is "expensive" enough to not get inlined unless [always_inline] is used
23+
// REGULAR: sil [always_inline] [Osize] @callee
24+
// IGNORED: sil [always_inline] [Osize] @callee
25+
sil [always_inline] [Osize] @callee : $@convention(thin) () -> () {
26+
bb0:
27+
%d1 = function_ref @foobar : $@convention(thin) () -> ()
28+
apply %d1() : $@convention(thin) () -> ()
29+
apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
46+
apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
48+
apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
50+
apply %d1() : $@convention(thin) () -> ()
51+
apply %d1() : $@convention(thin) () -> ()
52+
apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
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apply %d1() : $@convention(thin) () -> ()
55+
apply %d1() : $@convention(thin) () -> ()
56+
apply %d1() : $@convention(thin) () -> ()
57+
apply %d1() : $@convention(thin) () -> ()
58+
apply %d1() : $@convention(thin) () -> ()
59+
apply %d1() : $@convention(thin) () -> ()
60+
apply %d1() : $@convention(thin) () -> ()
61+
apply %d1() : $@convention(thin) () -> ()
62+
apply %d1() : $@convention(thin) () -> ()
63+
apply %d1() : $@convention(thin) () -> ()
64+
apply %d1() : $@convention(thin) () -> ()
65+
apply %d1() : $@convention(thin) () -> ()
66+
apply %d1() : $@convention(thin) () -> ()
67+
apply %d1() : $@convention(thin) () -> ()
68+
69+
%9999 = tuple()
70+
return %9999 : $()
71+
}

‎tools/sil-opt/SILOpt.cpp‎

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -274,6 +274,11 @@ static llvm::cl::opt<bool>
274274
llvm::cl::desc("Enable C++ interop."),
275275
llvm::cl::init(false));
276276

277+
static llvm::cl::opt<bool>
278+
IgnoreAlwaysInline("ignore-always-inline",
279+
llvm::cl::desc("Ignore [always_inline] attribute."),
280+
llvm::cl::init(false));
281+
277282
static void runCommandLineSelectedPasses(SILModule *Module,
278283
irgen::IRGenModule *IRGenMod) {
279284
auto &opts = Module->getOptions();
@@ -398,6 +403,7 @@ int main(int argc, char **argv) {
398403
}
399404

400405
SILOpts.EnableSpeculativeDevirtualization = EnableSpeculativeDevirtualization;
406+
SILOpts.IgnoreAlwaysInline = IgnoreAlwaysInline;
401407

402408
serialization::ExtendedValidationInfo extendedInfo;
403409
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> FileBufOrErr =

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