[clang][llvm][aarch64][win] Add a clang flag and module attribute for import call optimization, and remove LLVM flag #122831
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@llvm/pr-subscribers-clang-codegen @llvm/pr-subscribers-backend-aarch64 Author: Daniel Paoliello (dpaoliello) ChangesSwitches import call optimization from being enabled by an LLVM flag to instead using a module attribute, and creates a new Clang flag that will set that attribute. This addresses the concern raised in the original PR: <#121516 (comment)> This change also only creates the Called Global info if the module attribute is present, addressing this concern: <#122762 (review)> Full diff: https://github.com/llvm/llvm-project/pull/122831.diff 8 Files Affected:
diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def
index 0f4ed13d5f3d8c..e35e1a9e673dae 100644
--- a/clang/include/clang/Basic/CodeGenOptions.def
+++ b/clang/include/clang/Basic/CodeGenOptions.def
@@ -465,6 +465,10 @@ ENUM_CODEGENOPT(ZeroCallUsedRegs, llvm::ZeroCallUsedRegs::ZeroCallUsedRegsKind,
/// non-deleting destructors. (No effect on Microsoft ABI.)
CODEGENOPT(CtorDtorReturnThis, 1, 0)
+/// Enables emitting Import Call sections on supported targets that can be used
+/// by the Windows kernel to enable import call optimization.
+CODEGENOPT(ImportCallOptimization, 1, 0)
+
/// FIXME: Make DebugOptions its own top-level .def file.
#include "DebugOptions.def"
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index bbf5c0e7e7fd1a..8f4e5de74b20aa 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -7657,6 +7657,11 @@ def fexperimental_assignment_tracking_EQ : Joined<["-"], "fexperimental-assignme
def enable_tlsdesc : Flag<["-"], "enable-tlsdesc">,
MarshallingInfoFlag<CodeGenOpts<"EnableTLSDESC">>;
+def import_call_optimization : Flag<["-"], "import-call-optimization">,
+ HelpText<"Emit Import Call sections on supported targets that can be used "
+ "by the Windows kernel to enable import call optimization">,
+ MarshallingInfoFlag<CodeGenOpts<"ImportCallOptimization">>;
+
} // let Visibility = [CC1Option]
//===----------------------------------------------------------------------===//
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index dfb51b11e1d851..8970992b2b413b 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1291,6 +1291,11 @@ void CodeGenModule::Release() {
if (LangOpts.EHAsynch)
getModule().addModuleFlag(llvm::Module::Warning, "eh-asynch", 1);
+ // Emit Import Call section.
+ if (CodeGenOpts.ImportCallOptimization)
+ getModule().addModuleFlag(llvm::Module::Warning, "import-call-optimization",
+ 1);
+
// Indicate whether this Module was compiled with -fopenmp
if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd)
getModule().addModuleFlag(llvm::Module::Max, "openmp", LangOpts.OpenMP);
diff --git a/clang/test/CodeGen/import-call-optimization.c b/clang/test/CodeGen/import-call-optimization.c
new file mode 100644
index 00000000000000..cc4e37fda7bb1d
--- /dev/null
+++ b/clang/test/CodeGen/import-call-optimization.c
@@ -0,0 +1,5 @@
+// RUN: %clang_cc1 -import-call-optimization -emit-llvm %s -o - | FileCheck %s
+
+void f(void) {}
+
+// CHECK: !"import-call-optimization", i32 1}
diff --git a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
index 27e65d60122fd7..621b00dd8da8e9 100644
--- a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -78,11 +78,6 @@ static cl::opt<PtrauthCheckMode> PtrauthAuthChecks(
cl::desc("Check pointer authentication auth/resign failures"),
cl::init(Default));
-static cl::opt<bool> EnableImportCallOptimization(
- "aarch64-win-import-call-optimization", cl::Hidden,
- cl::desc("Enable import call optimization for AArch64 Windows"),
- cl::init(false));
-
#define DEBUG_TYPE "asm-printer"
namespace {
@@ -95,6 +90,7 @@ class AArch64AsmPrinter : public AsmPrinter {
#ifndef NDEBUG
unsigned InstsEmitted;
#endif
+ bool EnableImportCallOptimization = false;
DenseMap<MCSection *, std::vector<std::pair<MCSymbol *, MCSymbol *>>>
SectionToImportedFunctionCalls;
@@ -340,6 +336,9 @@ void AArch64AsmPrinter::emitStartOfAsmFile(Module &M) {
OutStreamer->emitSymbolAttribute(S, MCSA_Global);
OutStreamer->emitAssignment(
S, MCConstantExpr::create(Feat00Value, MMI->getContext()));
+
+ if (M.getModuleFlag("import-call-optimization"))
+ EnableImportCallOptimization = true;
}
if (!TT.isOSBinFormatELF())
@@ -945,7 +944,7 @@ void AArch64AsmPrinter::emitEndOfAsmFile(Module &M) {
// If import call optimization is enabled, emit the appropriate section.
// We do this whether or not we recorded any import calls.
- if (EnableImportCallOptimization && TT.isOSBinFormatCOFF()) {
+ if (EnableImportCallOptimization) {
OutStreamer->switchSection(getObjFileLowering().getImportCallSection());
// Section always starts with some magic.
@@ -3109,8 +3108,7 @@ void AArch64AsmPrinter::emitInstruction(const MachineInstr *MI) {
void AArch64AsmPrinter::recordIfImportCall(
const llvm::MachineInstr *BranchInst) {
- if (!EnableImportCallOptimization ||
- !TM.getTargetTriple().isOSBinFormatCOFF())
+ if (!EnableImportCallOptimization)
return;
auto [GV, OpFlags] = BranchInst->getMF()->tryGetCalledGlobal(BranchInst);
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index d4a114c275fb76..d02ec0cca62b5c 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -9577,7 +9577,8 @@ AArch64TargetLowering::LowerCall(CallLoweringInfo &CLI,
DAG.addNoMergeSiteInfo(Ret.getNode(), CLI.NoMerge);
DAG.addCallSiteInfo(Ret.getNode(), std::move(CSInfo));
- if (CalledGlobal)
+ if (CalledGlobal &&
+ MF.getFunction().getParent()->getModuleFlag("import-call-optimization"))
DAG.addCalledGlobal(Ret.getNode(), CalledGlobal, OpFlags);
return Ret;
}
@@ -9590,7 +9591,8 @@ AArch64TargetLowering::LowerCall(CallLoweringInfo &CLI,
DAG.addNoMergeSiteInfo(Chain.getNode(), CLI.NoMerge);
InGlue = Chain.getValue(1);
DAG.addCallSiteInfo(Chain.getNode(), std::move(CSInfo));
- if (CalledGlobal)
+ if (CalledGlobal &&
+ MF.getFunction().getParent()->getModuleFlag("import-call-optimization"))
DAG.addCalledGlobal(Chain.getNode(), CalledGlobal, OpFlags);
uint64_t CalleePopBytes =
diff --git a/llvm/test/CodeGen/AArch64/win-import-call-optimization-nocalls.ll b/llvm/test/CodeGen/AArch64/win-import-call-optimization-nocalls.ll
index 81d6d6369dcbf4..b17f2d113c0d29 100644
--- a/llvm/test/CodeGen/AArch64/win-import-call-optimization-nocalls.ll
+++ b/llvm/test/CodeGen/AArch64/win-import-call-optimization-nocalls.ll
@@ -1,4 +1,4 @@
-; RUN: llc -mtriple=aarch64-pc-windows-msvc -aarch64-win-import-call-optimization < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64-pc-windows-msvc < %s | FileCheck %s
define dso_local void @normal_call() local_unnamed_addr {
entry:
@@ -16,3 +16,6 @@ declare void @a() local_unnamed_addr
; CHECK-LABEL .section .impcall,"yi"
; CHECK-NEXT .asciz "Imp_Call_V1"
; CHECK-NOT .secnum
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"import-call-optimization", i32 1}
diff --git a/llvm/test/CodeGen/AArch64/win-import-call-optimization.ll b/llvm/test/CodeGen/AArch64/win-import-call-optimization.ll
index 6bb118ba1e1596..2cf0f8bb6baa5c 100644
--- a/llvm/test/CodeGen/AArch64/win-import-call-optimization.ll
+++ b/llvm/test/CodeGen/AArch64/win-import-call-optimization.ll
@@ -1,7 +1,4 @@
-; RUN: llc -mtriple=aarch64-pc-windows-msvc -aarch64-win-import-call-optimization < %s | FileCheck %s --check-prefix=CHECK-ENABLED
-; RUN: llc -mtriple=aarch64-pc-windows-msvc < %s | FileCheck %s --check-prefix=CHECK-DISABLED
-
-; CHECK-DISABLED-NOT: .section .impcall
+; RUN: llc -mtriple=aarch64-pc-windows-msvc < %s | FileCheck %s --check-prefix=CHECK
define dso_local void @normal_call() local_unnamed_addr section "nc_sect" {
entry:
@@ -9,40 +6,43 @@ entry:
call void @a()
ret void
}
-; CHECK-ENABLED-LABEL: normal_call:
-; CHECK-ENABLED: adrp [[ADRPREG:x[0-9]+]], __imp_a
-; CHECK-ENABLED-NEXT: ldr [[LDRREG:x[0-9]+]], [[[ADRPREG]], :lo12:__imp_a]
-; CHECK-ENABLED-NEXT: .Limpcall0:
-; CHECK-ENABLED-NEXT: blr [[LDRREG]]
-; CHECK-ENABLED-NEXT: .Limpcall1:
-; CHECK-ENABLED-NEXT: blr [[LDRREG]]
+; CHECK-LABEL: normal_call:
+; CHECK: adrp [[ADRPREG:x[0-9]+]], __imp_a
+; CHECK-NEXT: ldr [[LDRREG:x[0-9]+]], [[[ADRPREG]], :lo12:__imp_a]
+; CHECK-NEXT: .Limpcall0:
+; CHECK-NEXT: blr [[LDRREG]]
+; CHECK-NEXT: .Limpcall1:
+; CHECK-NEXT: blr [[LDRREG]]
define dso_local void @tail_call() local_unnamed_addr section "tc_sect" {
entry:
tail call void @b()
ret void
}
-; CHECK-ENABLED-LABEL: tail_call:
-; CHECK-ENABLED: adrp [[ADRPREG:x[0-9]+]], __imp_b
-; CHECK-ENABLED-NEXT: ldr [[LDRREG:x[0-9]+]], [[[ADRPREG]], :lo12:__imp_b]
-; CHECK-ENABLED-NEXT: .Limpcall2:
-; CHECK-ENABLED-NEXT: br [[LDRREG]]
+; CHECK-LABEL: tail_call:
+; CHECK: adrp [[ADRPREG:x[0-9]+]], __imp_b
+; CHECK-NEXT: ldr [[LDRREG:x[0-9]+]], [[[ADRPREG]], :lo12:__imp_b]
+; CHECK-NEXT: .Limpcall2:
+; CHECK-NEXT: br [[LDRREG]]
declare dllimport void @a() local_unnamed_addr
declare dllimport void @b() local_unnamed_addr
-; CHECK-ENABLED-LABEL .section .impcall,"yi"
-; CHECK-ENABLED-NEXT .asciz "Imp_Call_V1"
-; CHECK-ENABLED-NEXT .word 32
-; CHECK-ENABLED-NEXT .secnum nc_sect
-; CHECK-ENABLED-NEXT .word 19
-; CHECK-ENABLED-NEXT .secoffset .Limpcall0
-; CHECK-ENABLED-NEXT .symidx __imp_a
-; CHECK-ENABLED-NEXT .word 19
-; CHECK-ENABLED-NEXT .secoffset .Limpcall1
-; CHECK-ENABLED-NEXT .symidx __imp_a
-; CHECK-ENABLED-NEXT .word 20
-; CHECK-ENABLED-NEXT .secnum tc_sect
-; CHECK-ENABLED-NEXT .word 19
-; CHECK-ENABLED-NEXT .secoffset .Limpcall2
-; CHECK-ENABLED-NEXT .symidx __imp_b
+; CHECK-LABEL .section .impcall,"yi"
+; CHECK-NEXT .asciz "Imp_Call_V1"
+; CHECK-NEXT .word 32
+; CHECK-NEXT .secnum nc_sect
+; CHECK-NEXT .word 19
+; CHECK-NEXT .secoffset .Limpcall0
+; CHECK-NEXT .symidx __imp_a
+; CHECK-NEXT .word 19
+; CHECK-NEXT .secoffset .Limpcall1
+; CHECK-NEXT .symidx __imp_a
+; CHECK-NEXT .word 20
+; CHECK-NEXT .secnum tc_sect
+; CHECK-NEXT .word 19
+; CHECK-NEXT .secoffset .Limpcall2
+; CHECK-NEXT .symidx __imp_b
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"import-call-optimization", i32 1}
|
dpaoliello
changed the title
efriedma-quic
approved these changes
Jan 29, 2025
| @@ -945,7 +944,7 @@ void AArch64AsmPrinter::emitEndOfAsmFile(Module &M) { | |||
|
|
|||
| // If import call optimization is enabled, emit the appropriate section. | |||
| // We do this whether or not we recorded any import calls. | |||
| if (EnableImportCallOptimization && TT.isOSBinFormatCOFF()) { | |||
| if (EnableImportCallOptimization) { | |||
There was a problem hiding this comment.
Maybe leave the isOSBinFormatCOFF() checks so things don't explode if someone tries to use the metadata on a non-COFF target.
There was a problem hiding this comment.
EnableImportCallOptimization will only be set to true if we are targeting COFF (see AArch64AsmPrinter::emitStartOfAsmFile)
There was a problem hiding this comment.
Actually, I see your point: if this is every added for a non-COFF target we don't want to emit the COFF metadata.
…optimization, and remove LLVM flag
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Switches import call optimization from being enabled by an LLVM flag to instead using a module attribute, and creates a new Clang flag that will set that attribute. This addresses the concern raised in the original PR: #121516 (comment)
This change also only creates the Called Global info if the module attribute is present, addressing this concern: #122762 (review)