[clang][fat-lto-objects] Make module flags match non-FatLTO pipelines #83159
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Created using spr 1.3.4
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clang
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@llvm/pr-subscribers-clang-codegen Author: Paul Kirth (ilovepi) ChangesIn addition to being rather hard to follow, there isn't a good reason Additionally, we now test that output in the .llvm.lto section actually Full diff: https://github.com/llvm/llvm-project/pull/83159.diff 2 Files Affected:
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index a310825240237c..7b409e8c9a17ca 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -186,6 +186,11 @@ class EmitAssemblyHelper {
TargetTriple.getVendor() != llvm::Triple::Apple;
}
+ bool shouldEmitUnifiedLTOModueFlag() const {
+ return CodeGenOpts.UnifiedLTO &&
+ (CodeGenOpts.PrepareForThinLTO || shouldEmitRegularLTOSummary());
+ }
+
public:
EmitAssemblyHelper(DiagnosticsEngine &_Diags,
const HeaderSearchOptions &HeaderSearchOpts,
@@ -1036,7 +1041,8 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
if (!actionRequiresCodeGen(Action) && CodeGenOpts.VerifyModule)
MPM.addPass(VerifierPass());
- if (Action == Backend_EmitBC || Action == Backend_EmitLL) {
+ if (Action == Backend_EmitBC || Action == Backend_EmitLL ||
+ CodeGenOpts.FatLTO) {
if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
if (!TheModule->getModuleFlag("EnableSplitLTOUnit"))
TheModule->addModuleFlag(llvm::Module::Error, "EnableSplitLTOUnit",
@@ -1047,11 +1053,9 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
if (!ThinLinkOS)
return;
}
- if (CodeGenOpts.UnifiedLTO)
- TheModule->addModuleFlag(llvm::Module::Error, "UnifiedLTO", uint32_t(1));
MPM.addPass(ThinLTOBitcodeWriterPass(
*OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
- } else {
+ } else if (Action == Backend_EmitLL) {
MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists,
/*EmitLTOSummary=*/true));
}
@@ -1065,24 +1069,17 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
if (!TheModule->getModuleFlag("EnableSplitLTOUnit"))
TheModule->addModuleFlag(llvm::Module::Error, "EnableSplitLTOUnit",
uint32_t(1));
- if (CodeGenOpts.UnifiedLTO)
- TheModule->addModuleFlag(llvm::Module::Error, "UnifiedLTO", uint32_t(1));
}
- if (Action == Backend_EmitBC)
+ if (Action == Backend_EmitBC) {
MPM.addPass(BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
EmitLTOSummary));
- else
+ } else if (Action == Backend_EmitLL) {
MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists,
EmitLTOSummary));
+ }
}
- }
- if (CodeGenOpts.FatLTO) {
- // Set the EnableSplitLTOUnit and UnifiedLTO module flags, since FatLTO
- // uses a different action than Backend_EmitBC or Backend_EmitLL.
- if (!TheModule->getModuleFlag("EnableSplitLTOUnit"))
- TheModule->addModuleFlag(llvm::Module::Error, "EnableSplitLTOUnit",
- uint32_t(CodeGenOpts.EnableSplitLTOUnit));
- if (CodeGenOpts.UnifiedLTO && !TheModule->getModuleFlag("UnifiedLTO"))
+
+ if (shouldEmitUnifiedLTOModueFlag())
TheModule->addModuleFlag(llvm::Module::Error, "UnifiedLTO", uint32_t(1));
}
diff --git a/clang/test/CodeGen/fat-lto-objects.c b/clang/test/CodeGen/fat-lto-objects.c
index afce798c5c8194..459a6e4ecb8758 100644
--- a/clang/test/CodeGen/fat-lto-objects.c
+++ b/clang/test/CodeGen/fat-lto-objects.c
@@ -11,10 +11,11 @@
// RUN: llvm-objcopy --dump-section=.llvm.lto=%t.full.split.bc %t.full.split.o
// RUN: llvm-dis %t.full.split.bc -o - | FileCheck %s --check-prefixes=FULL,SPLIT,NOUNIFIED
+/// Full LTO always sets EnableSplitLTOUnit when the summary is used.
// RUN: %clang -cc1 -triple x86_64-unknown-linux-gnu -flto=full -ffat-lto-objects -emit-obj < %s -o %t.full.nosplit.o
// RUN: llvm-readelf -S %t.full.nosplit.o | FileCheck %s --check-prefixes=ELF
// RUN: llvm-objcopy --dump-section=.llvm.lto=%t.full.nosplit.bc %t.full.nosplit.o
-// RUN: llvm-dis %t.full.nosplit.bc -o - | FileCheck %s --check-prefixes=FULL,NOSPLIT,NOUNIFIED
+// RUN: llvm-dis %t.full.nosplit.bc -o - | FileCheck %s --check-prefixes=FULL,SPLIT,NOUNIFIED
// RUN: %clang -cc1 -triple x86_64-unknown-linux-gnu -flto=thin -fsplit-lto-unit -ffat-lto-objects -emit-obj < %s -o %t.thin.split.o
// RUN: llvm-readelf -S %t.thin.split.o | FileCheck %s --check-prefixes=ELF
@@ -34,6 +35,21 @@
// RUN: %clang -cc1 -triple x86_64-unknown-linux-gnu -flto=full -ffat-lto-objects -fsplit-lto-unit -S < %s -o - \
// RUN: | FileCheck %s --check-prefixes=ASM
+/// Make sure that FatLTO generates .llvm.lto sections that are the same as the output from normal LTO compilations
+// RUN: %clang -O2 --target=x86_64-unknown-linux-gnu -flto=full -fsplit-lto-unit -ffat-lto-objects -c %s -o %t.fatlto.full.o
+// RUN: llvm-objcopy --dump-section=.llvm.lto=%t.fatlto.full.bc %t.fatlto.full.o
+// RUN: llvm-dis < %t.fatlto.full.bc -o %t.fatlto.full.ll
+// RUN: %clang -O2 -Xclang -triple -Xclang x86_64-unknown-linux-gnu -flto=full -c %s -o %t.nofat.full.bc
+// RUN: llvm-dis < %t.nofat.full.bc -o %t.nofat.full.ll
+// RUN: diff %t.fatlto.full.ll %t.nofat.full.ll
+
+// RUN: %clang -O2 --target=x86_64-unknown-linux-gnu -flto=thin -ffat-lto-objects -c %s -o %t.fatlto.thin.o
+// RUN: llvm-objcopy --dump-section=.llvm.lto=%t.fatlto.thin.bc %t.fatlto.thin.o
+// RUN: llvm-dis < %t.fatlto.thin.bc -o %t.fatlto.thin.ll
+// RUN: %clang -O2 -Xclang -triple -Xclang x86_64-unknown-linux-gnu -flto=thin -c %s -o %t.nofat.thin.bc
+// RUN: llvm-dis < %t.nofat.thin.bc -o %t.nofat.thin.ll
+// RUN: diff %t.fatlto.thin.ll %t.nofat.thin.ll
+
/// Be sure we enable split LTO units correctly under -ffat-lto-objects.
// SPLIT: ![[#]] = !{i32 1, !"EnableSplitLTOUnit", i32 1}
// NOSPLIT: ![[#]] = !{i32 1, !"EnableSplitLTOUnit", i32 0}
@@ -51,6 +67,9 @@
// ASM-NEXT: .asciz "BC
// ASM-NEXT: .size .Lllvm.embedded.object
+const char* foo = "foo";
+
int test(void) {
+ const char* bar = "bar";
return 0xabcd;
}
|
|
@llvm/pr-subscribers-clang Author: Paul Kirth (ilovepi) ChangesIn addition to being rather hard to follow, there isn't a good reason Additionally, we now test that output in the .llvm.lto section actually Full diff: https://github.com/llvm/llvm-project/pull/83159.diff 2 Files Affected:
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index a310825240237c..7b409e8c9a17ca 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -186,6 +186,11 @@ class EmitAssemblyHelper {
TargetTriple.getVendor() != llvm::Triple::Apple;
}
+ bool shouldEmitUnifiedLTOModueFlag() const {
+ return CodeGenOpts.UnifiedLTO &&
+ (CodeGenOpts.PrepareForThinLTO || shouldEmitRegularLTOSummary());
+ }
+
public:
EmitAssemblyHelper(DiagnosticsEngine &_Diags,
const HeaderSearchOptions &HeaderSearchOpts,
@@ -1036,7 +1041,8 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
if (!actionRequiresCodeGen(Action) && CodeGenOpts.VerifyModule)
MPM.addPass(VerifierPass());
- if (Action == Backend_EmitBC || Action == Backend_EmitLL) {
+ if (Action == Backend_EmitBC || Action == Backend_EmitLL ||
+ CodeGenOpts.FatLTO) {
if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
if (!TheModule->getModuleFlag("EnableSplitLTOUnit"))
TheModule->addModuleFlag(llvm::Module::Error, "EnableSplitLTOUnit",
@@ -1047,11 +1053,9 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
if (!ThinLinkOS)
return;
}
- if (CodeGenOpts.UnifiedLTO)
- TheModule->addModuleFlag(llvm::Module::Error, "UnifiedLTO", uint32_t(1));
MPM.addPass(ThinLTOBitcodeWriterPass(
*OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
- } else {
+ } else if (Action == Backend_EmitLL) {
MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists,
/*EmitLTOSummary=*/true));
}
@@ -1065,24 +1069,17 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
if (!TheModule->getModuleFlag("EnableSplitLTOUnit"))
TheModule->addModuleFlag(llvm::Module::Error, "EnableSplitLTOUnit",
uint32_t(1));
- if (CodeGenOpts.UnifiedLTO)
- TheModule->addModuleFlag(llvm::Module::Error, "UnifiedLTO", uint32_t(1));
}
- if (Action == Backend_EmitBC)
+ if (Action == Backend_EmitBC) {
MPM.addPass(BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
EmitLTOSummary));
- else
+ } else if (Action == Backend_EmitLL) {
MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists,
EmitLTOSummary));
+ }
}
- }
- if (CodeGenOpts.FatLTO) {
- // Set the EnableSplitLTOUnit and UnifiedLTO module flags, since FatLTO
- // uses a different action than Backend_EmitBC or Backend_EmitLL.
- if (!TheModule->getModuleFlag("EnableSplitLTOUnit"))
- TheModule->addModuleFlag(llvm::Module::Error, "EnableSplitLTOUnit",
- uint32_t(CodeGenOpts.EnableSplitLTOUnit));
- if (CodeGenOpts.UnifiedLTO && !TheModule->getModuleFlag("UnifiedLTO"))
+
+ if (shouldEmitUnifiedLTOModueFlag())
TheModule->addModuleFlag(llvm::Module::Error, "UnifiedLTO", uint32_t(1));
}
diff --git a/clang/test/CodeGen/fat-lto-objects.c b/clang/test/CodeGen/fat-lto-objects.c
index afce798c5c8194..459a6e4ecb8758 100644
--- a/clang/test/CodeGen/fat-lto-objects.c
+++ b/clang/test/CodeGen/fat-lto-objects.c
@@ -11,10 +11,11 @@
// RUN: llvm-objcopy --dump-section=.llvm.lto=%t.full.split.bc %t.full.split.o
// RUN: llvm-dis %t.full.split.bc -o - | FileCheck %s --check-prefixes=FULL,SPLIT,NOUNIFIED
+/// Full LTO always sets EnableSplitLTOUnit when the summary is used.
// RUN: %clang -cc1 -triple x86_64-unknown-linux-gnu -flto=full -ffat-lto-objects -emit-obj < %s -o %t.full.nosplit.o
// RUN: llvm-readelf -S %t.full.nosplit.o | FileCheck %s --check-prefixes=ELF
// RUN: llvm-objcopy --dump-section=.llvm.lto=%t.full.nosplit.bc %t.full.nosplit.o
-// RUN: llvm-dis %t.full.nosplit.bc -o - | FileCheck %s --check-prefixes=FULL,NOSPLIT,NOUNIFIED
+// RUN: llvm-dis %t.full.nosplit.bc -o - | FileCheck %s --check-prefixes=FULL,SPLIT,NOUNIFIED
// RUN: %clang -cc1 -triple x86_64-unknown-linux-gnu -flto=thin -fsplit-lto-unit -ffat-lto-objects -emit-obj < %s -o %t.thin.split.o
// RUN: llvm-readelf -S %t.thin.split.o | FileCheck %s --check-prefixes=ELF
@@ -34,6 +35,21 @@
// RUN: %clang -cc1 -triple x86_64-unknown-linux-gnu -flto=full -ffat-lto-objects -fsplit-lto-unit -S < %s -o - \
// RUN: | FileCheck %s --check-prefixes=ASM
+/// Make sure that FatLTO generates .llvm.lto sections that are the same as the output from normal LTO compilations
+// RUN: %clang -O2 --target=x86_64-unknown-linux-gnu -flto=full -fsplit-lto-unit -ffat-lto-objects -c %s -o %t.fatlto.full.o
+// RUN: llvm-objcopy --dump-section=.llvm.lto=%t.fatlto.full.bc %t.fatlto.full.o
+// RUN: llvm-dis < %t.fatlto.full.bc -o %t.fatlto.full.ll
+// RUN: %clang -O2 -Xclang -triple -Xclang x86_64-unknown-linux-gnu -flto=full -c %s -o %t.nofat.full.bc
+// RUN: llvm-dis < %t.nofat.full.bc -o %t.nofat.full.ll
+// RUN: diff %t.fatlto.full.ll %t.nofat.full.ll
+
+// RUN: %clang -O2 --target=x86_64-unknown-linux-gnu -flto=thin -ffat-lto-objects -c %s -o %t.fatlto.thin.o
+// RUN: llvm-objcopy --dump-section=.llvm.lto=%t.fatlto.thin.bc %t.fatlto.thin.o
+// RUN: llvm-dis < %t.fatlto.thin.bc -o %t.fatlto.thin.ll
+// RUN: %clang -O2 -Xclang -triple -Xclang x86_64-unknown-linux-gnu -flto=thin -c %s -o %t.nofat.thin.bc
+// RUN: llvm-dis < %t.nofat.thin.bc -o %t.nofat.thin.ll
+// RUN: diff %t.fatlto.thin.ll %t.nofat.thin.ll
+
/// Be sure we enable split LTO units correctly under -ffat-lto-objects.
// SPLIT: ![[#]] = !{i32 1, !"EnableSplitLTOUnit", i32 1}
// NOSPLIT: ![[#]] = !{i32 1, !"EnableSplitLTOUnit", i32 0}
@@ -51,6 +67,9 @@
// ASM-NEXT: .asciz "BC
// ASM-NEXT: .size .Lllvm.embedded.object
+const char* foo = "foo";
+
int test(void) {
+ const char* bar = "bar";
return 0xabcd;
}
|
ilovepi
requested review from
petrhosek,
MaskRay,
aeubanks and
teresajohnson
| @@ -1036,7 +1041,8 @@ void EmitAssemblyHelper::RunOptimizationPipeline( | |||
| if (!actionRequiresCodeGen(Action) && CodeGenOpts.VerifyModule) | |||
| MPM.addPass(VerifierPass()); | |||
|
|
|||
| if (Action == Backend_EmitBC || Action == Backend_EmitLL) { | |||
| if (Action == Backend_EmitBC || Action == Backend_EmitLL || | |||
| CodeGenOpts.FatLTO) { | |||
There was a problem hiding this comment.
What is the Action type with FatLTO?
There was a problem hiding this comment.
I believe its Backend_EmitObj . I think that gets a little complicated when -S or -emit-llvm is passed, since I think we then select Backend_EmitLL or Backend_EmitBC.
llvm-project/clang/lib/Driver/Driver.cpp
Line 4770 in d82e93e
There was a problem hiding this comment.
I see, I guess then the check for the CodeGenOpt is needed here to catch this case.
teresajohnson
approved these changes
Feb 28, 2024
| @@ -1036,7 +1041,8 @@ void EmitAssemblyHelper::RunOptimizationPipeline( | |||
| if (!actionRequiresCodeGen(Action) && CodeGenOpts.VerifyModule) | |||
| MPM.addPass(VerifierPass()); | |||
|
|
|||
| if (Action == Backend_EmitBC || Action == Backend_EmitLL) { | |||
| if (Action == Backend_EmitBC || Action == Backend_EmitLL || | |||
| CodeGenOpts.FatLTO) { | |||
There was a problem hiding this comment.
I see, I guess then the check for the CodeGenOpt is needed here to catch this case.
|
Hmm, not sure why this comes out differently on windows in the presubmit. |
… same Created using spr 1.3.4
|
Seems like "PIE Level" is different, Lets see if passing |
Created using spr 1.3.4
ilovepi
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users/ilovepi/spr/clangfat-lto-objects-make-module-flags-match-non-fatlto-pipelines
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Mar 7, 2024
…llvm#83159) In addition to being rather hard to follow, there isn't a good reason why FatLTO shouldn't just share the same code for setting module flags for (Thin)LTO. This patch simplifies the logic and makes sure we use set these flags in a consistent way, independent of FatLTO. Additionally, we now test that output in the .llvm.lto section actually matches the output from Full and Thin LTO compilation. (cherry picked from commit 7d8b50a)
llvmbot
pushed a commit
to llvmbot/llvm-project
that referenced
this pull request
Mar 11, 2024
…llvm#83159) In addition to being rather hard to follow, there isn't a good reason why FatLTO shouldn't just share the same code for setting module flags for (Thin)LTO. This patch simplifies the logic and makes sure we use set these flags in a consistent way, independent of FatLTO. Additionally, we now test that output in the .llvm.lto section actually matches the output from Full and Thin LTO compilation. (cherry picked from commit 7d8b50a)
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In addition to being rather hard to follow, there isn't a good reason
why FatLTO shouldn't just share the same code for setting module flags
for (Thin)LTO. This patch simplifies the logic and makes sure we use set
these flags in a consistent way, independent of FatLTO.
Additionally, we now test that output in the .llvm.lto section actually
matches the output from Full and Thin LTO compilation.