[llvm] [AsmPrinter] Fix handling in emitGlobalConstantImpl for AIX (PR #116255)
Zaara Syeda via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 18 13:28:20 PST 2024
https://github.com/syzaara updated https://github.com/llvm/llvm-project/pull/116255
>From 647beb7ad9dec6cf23f272f4f3f461c0cafde74d Mon Sep 17 00:00:00 2001
From: Zaara Syeda <syzaara at ca.ibm.com>
Date: Thu, 14 Nov 2024 16:42:16 +0000
Subject: [PATCH 1/3] [AsmPrinter] Fix handling in emitGlobalConstantImpl for
AIX
When GlobalMerge creates a MergedGlobal of statics all initialized to zero,
emitGlobalConstantImpl sees a ConstantAggregateZero. This results in just
emitting zeros followed by labels for the aliases. We need to handle it more
like how emitGlobalConstantStruct does by emitting each global inside the
aggregate.
Co-authored-by: Hubert Tong <hubert.reinterpretcast at gmail.com>
---
llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp | 26 +++++++++-
.../PowerPC/global-merge-aix-sections.ll | 52 +++++++++++++++++++
2 files changed, 77 insertions(+), 1 deletion(-)
create mode 100644 llvm/test/CodeGen/PowerPC/global-merge-aix-sections.ll
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 1d24fa44a5cea0..b463c291ee3c45 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -3849,6 +3849,8 @@ static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
AsmPrinter &AP, const Constant *BaseCV,
uint64_t Offset,
AsmPrinter::AliasMapTy *AliasList) {
+ assert(!AliasList || AP.TM.getTargetTriple().isOSBinFormatXCOFF() &&
+ "AliasList only expected for XCOFF");
emitGlobalAliasInline(AP, Offset, AliasList);
uint64_t Size = DL.getTypeAllocSize(CV->getType());
@@ -3858,7 +3860,29 @@ static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
if (!BaseCV && CV->hasOneUse())
BaseCV = dyn_cast<Constant>(CV->user_back());
- if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
+ if (isa<ConstantAggregateZero>(CV)) {
+ StructType *structType = llvm::dyn_cast<llvm::StructType>(CV->getType());
+ if (structType && AliasList) {
+ // Handle cases of aliases to direct struct elements
+ const StructLayout *Layout = DL.getStructLayout(structType);
+ uint64_t SizeSoFar = 0;
+ for (unsigned int i = 0, n = structType->getNumElements(); i < n - 1;
+ ++i) {
+ emitGlobalAliasInline(AP, Offset + SizeSoFar, AliasList);
+ uint64_t GapToNext = Layout->getElementOffset(i + 1) - SizeSoFar;
+ AP.OutStreamer->emitZeros(GapToNext);
+ SizeSoFar += GapToNext;
+ }
+ emitGlobalAliasInline(AP, Offset + SizeSoFar, AliasList);
+ uint64_t Size = DL.getTypeAllocSize(structType);
+ AP.OutStreamer->emitZeros(Size - SizeSoFar);
+ return;
+ } else {
+ return AP.OutStreamer->emitZeros(Size);
+ }
+ }
+
+ if (isa<UndefValue>(CV))
return AP.OutStreamer->emitZeros(Size);
if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
diff --git a/llvm/test/CodeGen/PowerPC/global-merge-aix-sections.ll b/llvm/test/CodeGen/PowerPC/global-merge-aix-sections.ll
new file mode 100644
index 00000000000000..0fb313b572677b
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/global-merge-aix-sections.ll
@@ -0,0 +1,52 @@
+; RUN: rm -rf %t
+; RUN: mkdir -p %t
+
+; RUN: llc -verify-machineinstrs -mtriple powerpc64-ibm-aix-xcoff -mcpu=pwr8 < %s | FileCheck %s
+
+; RUN: llc -verify-machineinstrs -mtriple powerpc64-ibm-aix-xcoff -mcpu=pwr8 --filetype=obj -o %t/global-merge-aix-sections.o < %s
+; RUN; llvm-objdump --syms %t/global-merge-aix-sections.o | FileCheck %s --check-prefix=DATA
+
+%struct.Example = type { i32, i8 }
+
+ at y = internal global i32 0, section "mycsect", align 4
+ at z = internal global i32 0, section "mycsect", align 4
+ at l = internal global i32 0, align 4
+ at u = internal global i16 0, section "mycsect", align 2
+ at myStruct1 = internal global %struct.Example zeroinitializer, section "mycsect", align 4
+
+; Function Attrs: nounwind
+define void @g() {
+entry:
+ tail call void @f(ptr noundef nonnull @y, ptr noundef nonnull @z)
+ tail call void @f(ptr noundef nonnull @l, ptr noundef nonnull @z)
+ tail call void @h(ptr noundef nonnull @u)
+ tail call void @s(ptr noundef nonnull @myStruct1)
+ ret void
+}
+
+declare void @f(ptr noundef, ptr noundef)
+declare void @h(ptr noundef)
+declare void @s(ptr noundef)
+
+; CHECK: .csect mycsect[RW],2
+; CHECK-NEXT: .lglobl u # @_MergedGlobals
+; CHECK-NEXT: .lglobl y
+; CHECK-NEXT: .lglobl z
+; CHECK-NEXT: .lglobl myStruct1
+; CHECK-NEXT: .align 2
+; CHECK-NEXT: L.._MergedGlobals:
+; CHECK-NEXT: u:
+; CHECK-NEXT: .space 2
+; CHECK-NEXT: .space 2
+; CHECK-NEXT: y:
+; CHECK-NEXT: .space 4
+; CHECK-NEXT: z:
+; CHECK-NEXT: .space 4
+; CHECK-NEXT: myStruct1:
+; CHECK-NEXT: .space 8
+
+; DATA: 00000078 l O .data 00000014 mycsect
+; DATA-NEXT: 00000078 l O .data (csect: mycsect) 00000000 u
+; DATA-NEXT: 0000007c l O .data (csect: mycsect) 00000000 y
+; DATA-NEXT: 00000080 l O .data (csect: mycsect) 00000000 z
+; DATA-NEXT: 00000084 l O .data (csect: mycsect) 00000000 myStruct1
>From 93a5f214f796ba0e74380bbbaaa3119e3837596a Mon Sep 17 00:00:00 2001
From: Zaara Syeda <syzaara at ca.ibm.com>
Date: Mon, 18 Nov 2024 16:54:24 +0000
Subject: [PATCH 2/3] Address review comments
---
llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index b463c291ee3c45..715d55016bbfd1 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -3861,8 +3861,8 @@ static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
BaseCV = dyn_cast<Constant>(CV->user_back());
if (isa<ConstantAggregateZero>(CV)) {
- StructType *structType = llvm::dyn_cast<llvm::StructType>(CV->getType());
- if (structType && AliasList) {
+ StructType *structType;
+ if (AliasList && (structType = llvm::dyn_cast<StructType>(CV->getType()))) {
// Handle cases of aliases to direct struct elements
const StructLayout *Layout = DL.getStructLayout(structType);
uint64_t SizeSoFar = 0;
>From 8949d8a5f4bd881dfd4819bb0fe4c966328dd186 Mon Sep 17 00:00:00 2001
From: Zaara Syeda <syzaara at ca.ibm.com>
Date: Mon, 18 Nov 2024 21:41:41 +0000
Subject: [PATCH 3/3] Address review
---
llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 715d55016bbfd1..030d0e1c82ab73 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -3868,13 +3868,11 @@ static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
uint64_t SizeSoFar = 0;
for (unsigned int i = 0, n = structType->getNumElements(); i < n - 1;
++i) {
- emitGlobalAliasInline(AP, Offset + SizeSoFar, AliasList);
uint64_t GapToNext = Layout->getElementOffset(i + 1) - SizeSoFar;
AP.OutStreamer->emitZeros(GapToNext);
SizeSoFar += GapToNext;
+ emitGlobalAliasInline(AP, Offset + SizeSoFar, AliasList);
}
- emitGlobalAliasInline(AP, Offset + SizeSoFar, AliasList);
- uint64_t Size = DL.getTypeAllocSize(structType);
AP.OutStreamer->emitZeros(Size - SizeSoFar);
return;
} else {
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