[llvm] 7daa65a - Reland "[NVPTX] Use .common linkage for common globals" (#86824)
via llvm-commits
llvm-commits at lists.llvm.org
Fri Mar 29 11:58:45 PDT 2024
Author: Alex MacLean
Date: 2024-03-29T11:58:41-07:00
New Revision: 7daa65a088c00891662d5e7e162e5f8f3283f799
URL: https://github.com/llvm/llvm-project/commit/7daa65a088c00891662d5e7e162e5f8f3283f799
DIFF: https://github.com/llvm/llvm-project/commit/7daa65a088c00891662d5e7e162e5f8f3283f799.diff
LOG: Reland "[NVPTX] Use .common linkage for common globals" (#86824)
Switch from `.weak` to `.common` linkage for common global variables
where possible. The `.common` linkage is described in
[PTX ISA 11.6.4. Linking Directives: .common]
(https://docs.nvidia.com/cuda/parallel-thread-execution/index.html#linking-directives-common)
> Declares identifier to be globally visible but “common”.
>
>Common symbols are similar to globally visible symbols. However
multiple object files may declare the same common symbol and they may
have different types and sizes and references to a symbol get resolved
against a common symbol with the largest size.
>
>Only one object file can initialize a common symbol and that must have
the largest size among all other definitions of that common symbol from
different object files.
>
>.common linking directive can be used only on variables with .global
storage. It cannot be used on function symbols or on symbols with opaque
type.
I've updated the logic and tests to only use `.common` for PTX 5.0 or
greater and verified that the new tests now pass with `ptxas`.
Added:
llvm/test/CodeGen/NVPTX/common-linkage.ll
Modified:
llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
llvm/test/CodeGen/NVPTX/weak-global.ll
Removed:
################################################################################
diff --git a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
index ece9821a2d0d9f..9f31b72bbceb1f 100644
--- a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
@@ -1022,7 +1022,6 @@ void NVPTXAsmPrinter::printModuleLevelGV(const GlobalVariable *GVar,
const DataLayout &DL = getDataLayout();
// GlobalVariables are always constant pointers themselves.
- PointerType *PTy = GVar->getType();
Type *ETy = GVar->getValueType();
if (GVar->hasExternalLinkage()) {
@@ -1030,6 +1029,9 @@ void NVPTXAsmPrinter::printModuleLevelGV(const GlobalVariable *GVar,
O << ".visible ";
else
O << ".extern ";
+ } else if (STI.getPTXVersion() >= 50 && GVar->hasCommonLinkage() &&
+ GVar->getAddressSpace() == ADDRESS_SPACE_GLOBAL) {
+ O << ".common ";
} else if (GVar->hasLinkOnceLinkage() || GVar->hasWeakLinkage() ||
GVar->hasAvailableExternallyLinkage() ||
GVar->hasCommonLinkage()) {
@@ -1141,7 +1143,7 @@ void NVPTXAsmPrinter::printModuleLevelGV(const GlobalVariable *GVar,
}
O << ".";
- emitPTXAddressSpace(PTy->getAddressSpace(), O);
+ emitPTXAddressSpace(GVar->getAddressSpace(), O);
if (isManaged(*GVar)) {
if (STI.getPTXVersion() < 40 || STI.getSmVersion() < 30) {
@@ -1170,8 +1172,8 @@ void NVPTXAsmPrinter::printModuleLevelGV(const GlobalVariable *GVar,
// Ptx allows variable initilization only for constant and global state
// spaces.
if (GVar->hasInitializer()) {
- if ((PTy->getAddressSpace() == ADDRESS_SPACE_GLOBAL) ||
- (PTy->getAddressSpace() == ADDRESS_SPACE_CONST)) {
+ if ((GVar->getAddressSpace() == ADDRESS_SPACE_GLOBAL) ||
+ (GVar->getAddressSpace() == ADDRESS_SPACE_CONST)) {
const Constant *Initializer = GVar->getInitializer();
// 'undef' is treated as there is no value specified.
if (!Initializer->isNullValue() && !isa<UndefValue>(Initializer)) {
@@ -1186,7 +1188,7 @@ void NVPTXAsmPrinter::printModuleLevelGV(const GlobalVariable *GVar,
!isa<UndefValue>(GVar->getInitializer())) {
report_fatal_error("initial value of '" + GVar->getName() +
"' is not allowed in addrspace(" +
- Twine(PTy->getAddressSpace()) + ")");
+ Twine(GVar->getAddressSpace()) + ")");
}
}
}
@@ -1205,8 +1207,8 @@ void NVPTXAsmPrinter::printModuleLevelGV(const GlobalVariable *GVar,
ElementSize = DL.getTypeStoreSize(ETy);
// Ptx allows variable initilization only for constant and
// global state spaces.
- if (((PTy->getAddressSpace() == ADDRESS_SPACE_GLOBAL) ||
- (PTy->getAddressSpace() == ADDRESS_SPACE_CONST)) &&
+ if (((GVar->getAddressSpace() == ADDRESS_SPACE_GLOBAL) ||
+ (GVar->getAddressSpace() == ADDRESS_SPACE_CONST)) &&
GVar->hasInitializer()) {
const Constant *Initializer = GVar->getInitializer();
if (!isa<UndefValue>(Initializer) && !Initializer->isNullValue()) {
diff --git a/llvm/test/CodeGen/NVPTX/common-linkage.ll b/llvm/test/CodeGen/NVPTX/common-linkage.ll
new file mode 100644
index 00000000000000..976074e12ba667
--- /dev/null
+++ b/llvm/test/CodeGen/NVPTX/common-linkage.ll
@@ -0,0 +1,29 @@
+; RUN: llc < %s -march=nvptx -mcpu=sm_20 -mattr=+ptx43 | FileCheck %s --check-prefixes CHECK,PTX43
+; RUN: llc < %s -march=nvptx -mcpu=sm_20 -mattr=+ptx50 | FileCheck %s --check-prefixes CHECK,PTX50
+; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 -mattr=+ptx43 | %ptxas-verify %}
+; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 -mattr=+ptx50 | %ptxas-verify %}
+
+; PTX43: .weak .global .align 4 .u32 g
+; PTX50: .common .global .align 4 .u32 g
+ at g = common addrspace(1) global i32 0, align 4
+
+; CHECK: .weak .const .align 4 .u32 c
+ at c = common addrspace(4) global i32 0, align 4
+
+; CHECK: .weak .shared .align 4 .u32 s
+ at s = common addrspace(3) global i32 0, align 4
+
+define i32 @f1() {
+ %1 = load i32, ptr addrspace(1) @g
+ ret i32 %1
+}
+
+define i32 @f4() {
+ %1 = load i32, ptr addrspace(4) @c
+ ret i32 %1
+}
+
+define i32 @f3() {
+ %1 = load i32, ptr addrspace(3) @s
+ ret i32 %1
+}
diff --git a/llvm/test/CodeGen/NVPTX/weak-global.ll b/llvm/test/CodeGen/NVPTX/weak-global.ll
index dd0160d1c0a654..c5467aad08a360 100644
--- a/llvm/test/CodeGen/NVPTX/weak-global.ll
+++ b/llvm/test/CodeGen/NVPTX/weak-global.ll
@@ -1,7 +1,10 @@
-; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 | FileCheck %s
-; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 | %ptxas-verify %}
+; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -mattr=+ptx43 | FileCheck %s --check-prefix PTX43
+; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -mattr=+ptx50 | FileCheck %s --check-prefix PTX50
+; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 -mattr=+ptx43 | %ptxas-verify %}
+; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 -mattr=+ptx50 | %ptxas-verify %}
-; CHECK: .weak .global .align 4 .u32 g
+; PTX43: .weak .global .align 4 .u32 g
+; PTX50: .common .global .align 4 .u32 g
@g = common addrspace(1) global i32 zeroinitializer
define i32 @func0() {
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