[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-28 Thread Paul Kirth via cfe-commits 

https://github.com/ilovepi closed 
https://github.com/llvm/llvm-project/pull/83159
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[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-28 Thread Paul Kirth via cfe-commits 

https://github.com/ilovepi updated 
https://github.com/llvm/llvm-project/pull/83159

>From 0a37b8e52fe5e17fff3f6e88bf25f1969bbe8bb4 Mon Sep 17 00:00:00 2001
From: Paul Kirth 
Date: Tue, 27 Feb 2024 17:43:58 +
Subject: [PATCH 1/3] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20in?=
 =?UTF-8?q?itial=20version?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Created using spr 1.3.4
---
 clang/lib/CodeGen/BackendUtil.cpp| 29 +---
 clang/test/CodeGen/fat-lto-objects.c | 21 +++-
 2 files changed, 33 insertions(+), 17 deletions(-)

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 ,
@@ -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 ? >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

[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-28 Thread Paul Kirth via cfe-commits 

ilovepi wrote:

Seems like "PIE Level" is different, Lets see if passing `-fPIE` will satisfy 
the windows bot

https://github.com/llvm/llvm-project/pull/83159
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[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-28 Thread Paul Kirth via cfe-commits 

https://github.com/ilovepi updated 
https://github.com/llvm/llvm-project/pull/83159

>From 0a37b8e52fe5e17fff3f6e88bf25f1969bbe8bb4 Mon Sep 17 00:00:00 2001
From: Paul Kirth 
Date: Tue, 27 Feb 2024 17:43:58 +
Subject: [PATCH 1/2] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20in?=
 =?UTF-8?q?itial=20version?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Created using spr 1.3.4
---
 clang/lib/CodeGen/BackendUtil.cpp| 29 +---
 clang/test/CodeGen/fat-lto-objects.c | 21 +++-
 2 files changed, 33 insertions(+), 17 deletions(-)

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 ,
@@ -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 ? >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

[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-28 Thread Paul Kirth via cfe-commits 

ilovepi wrote:

Hmm, not sure why this comes out differently on windows in the presubmit.

https://github.com/llvm/llvm-project/pull/83159
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[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-28 Thread Teresa Johnson via cfe-commits 


@@ -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) {

teresajohnson wrote:

I see, I guess then the check for the CodeGenOpt is needed here to catch this 
case.

https://github.com/llvm/llvm-project/pull/83159
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[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-28 Thread Teresa Johnson via cfe-commits 

https://github.com/teresajohnson approved this pull request.


https://github.com/llvm/llvm-project/pull/83159
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[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-28 Thread Teresa Johnson via cfe-commits 

https://github.com/teresajohnson edited 
https://github.com/llvm/llvm-project/pull/83159
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[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-27 Thread Paul Kirth via cfe-commits 


@@ -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) {

ilovepi wrote:

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`. 
https://github.com/llvm/llvm-project/blob/d82e93e7f129d9e8b72570efdf4a15d6ec3d4336/clang/lib/Driver/Driver.cpp#L4770


https://github.com/llvm/llvm-project/pull/83159
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[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-27 Thread Teresa Johnson via cfe-commits 


@@ -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) {

teresajohnson wrote:

What is the Action type with FatLTO?

https://github.com/llvm/llvm-project/pull/83159
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[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-27 Thread via cfe-commits 

llvmbot wrote:




@llvm/pr-subscribers-clang

Author: Paul Kirth (ilovepi)


Changes

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.


---
Full diff: https://github.com/llvm/llvm-project/pull/83159.diff


2 Files Affected:

- (modified) clang/lib/CodeGen/BackendUtil.cpp (+13-16) 
- (modified) clang/test/CodeGen/fat-lto-objects.c (+20-1) 


``diff
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 ,
@@ -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 ? >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

[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-27 Thread via cfe-commits 

llvmbot wrote:




@llvm/pr-subscribers-clang-codegen

Author: Paul Kirth (ilovepi)


Changes

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.


---
Full diff: https://github.com/llvm/llvm-project/pull/83159.diff


2 Files Affected:

- (modified) clang/lib/CodeGen/BackendUtil.cpp (+13-16) 
- (modified) clang/test/CodeGen/fat-lto-objects.c (+20-1) 


``diff
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 ,
@@ -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 ? >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

[clang] [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (PR #83159)

2024-02-27 Thread Paul Kirth via cfe-commits 

https://github.com/ilovepi created 
https://github.com/llvm/llvm-project/pull/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.


>From 0a37b8e52fe5e17fff3f6e88bf25f1969bbe8bb4 Mon Sep 17 00:00:00 2001
From: Paul Kirth 
Date: Tue, 27 Feb 2024 17:43:58 +
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
 =?UTF-8?q?l=20version?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Created using spr 1.3.4
---
 clang/lib/CodeGen/BackendUtil.cpp| 29 +---
 clang/test/CodeGen/fat-lto-objects.c | 21 +++-
 2 files changed, 33 insertions(+), 17 deletions(-)

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 ,
@@ -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 ? >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