[clang] [clang][CodeGen] Omit pre-opt link when post-opt is link requested (PR #85672)

[Jacob Lambert via cfe-commits]

https://github.com/lamb-j updated https://github.com/llvm/llvm-project/pull/85672

>From aff1a762a73ce30cde38a6fcbbed8a3e4f0b5366 Mon Sep 17 00:00:00 2001
From: Jacob Lambert <jacob.lambert at amd.com>
Date: Mon, 18 Mar 2024 10:19:38 -0700
Subject: [PATCH 1/4] [clang][CodeGen] Omit pre-opt link when post-opt link
 requested

Currently, when the -relink-builtin-bitcodes-postop option is used
we link builtin bitcodes twice: once before optimization, and again
after optimization.

With this change, we omit the pre-opt linking when the option is
set, and we rename the option to the following:

  -link-builtin-bitcodes-postopt
---
 clang/lib/CodeGen/BackendUtil.cpp       | 13 +++++--------
 clang/lib/CodeGen/CodeGenAction.cpp     |  6 +++---
 clang/lib/CodeGen/LinkInModulesPass.cpp |  4 ----
 3 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 82b30b8d815629..c5571eb15ce3a9 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -112,9 +112,9 @@ static cl::opt<bool> ClSanitizeOnOptimizerEarlyEP(
 extern cl::opt<InstrProfCorrelator::ProfCorrelatorKind> ProfileCorrelate;
 
 // Re-link builtin bitcodes after optimization
-cl::opt<bool> ClRelinkBuiltinBitcodePostop(
-    "relink-builtin-bitcode-postop", cl::Optional,
-    cl::desc("Re-link builtin bitcodes after optimization."), cl::init(false));
+cl::opt<bool> ClLinkBuiltinBitcodePostopt(
+    "link-builtin-bitcode-postopt", cl::Optional,
+    cl::desc("Link builtin bitcodes after optimization."), cl::init(false));
 } // namespace llvm
 
 namespace {
@@ -1051,11 +1051,8 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
     }
   }
 
-  // Re-link against any bitcodes supplied via the -mlink-builtin-bitcode option
-  // Some optimizations may generate new function calls that would not have
-  // been linked pre-optimization (i.e. fused sincos calls generated by
-  // AMDGPULibCalls::fold_sincos.)
-  if (ClRelinkBuiltinBitcodePostop)
+  // Link against bitcodes supplied via the -mlink-builtin-bitcode option
+  if (ClLinkBuiltinBitcodePostopt)
     MPM.addPass(LinkInModulesPass(BC, false));
 
   // Add a verifier pass if requested. We don't have to do this if the action
diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
index bb9aaba025fa59..51f54d178672d1 100644
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -58,7 +58,7 @@ using namespace llvm;
 #define DEBUG_TYPE "codegenaction"
 
 namespace llvm {
-extern cl::opt<bool> ClRelinkBuiltinBitcodePostop;
+extern cl::opt<bool> ClLinkBuiltinBitcodePostopt;
 }
 
 namespace clang {
@@ -359,7 +359,7 @@ void BackendConsumer::HandleTranslationUnit(ASTContext &C) {
   }
 
   // Link each LinkModule into our module.
-  if (LinkInModules(getModule()))
+  if (!LinkBuiltinBitcodesPostopt && LinkInModules(getModule()))
     return;
 
   for (auto &F : getModule()->functions()) {
@@ -1213,7 +1213,7 @@ void CodeGenAction::ExecuteAction() {
                          std::move(LinkModules), *VMContext, nullptr);
 
   // Link in each pending link module.
-  if (Result.LinkInModules(&*TheModule))
+  if (!LinkBuiltinBitcodesPostopt && Result.LinkInModules(&*TheModule))
     return;
 
   // PR44896: Force DiscardValueNames as false. DiscardValueNames cannot be
diff --git a/clang/lib/CodeGen/LinkInModulesPass.cpp b/clang/lib/CodeGen/LinkInModulesPass.cpp
index 929539cc8f3346..ce1c0ebe046a61 100644
--- a/clang/lib/CodeGen/LinkInModulesPass.cpp
+++ b/clang/lib/CodeGen/LinkInModulesPass.cpp
@@ -28,10 +28,6 @@ PreservedAnalyses LinkInModulesPass::run(Module &M, ModuleAnalysisManager &AM) {
   if (!BC)
     return PreservedAnalyses::all();
 
-  // Re-load bitcode modules from files
-  if (BC->ReloadModules(&M))
-    report_fatal_error("Bitcode module re-loading failed, aborted!");
-
   if (BC->LinkInModules(&M, ShouldLinkFiles))
     report_fatal_error("Bitcode module re-linking failed, aborted!");
 

>From 9a6757c9497019dbc2c9c0d449c0d1cbc70c98fd Mon Sep 17 00:00:00 2001
From: Jacob Lambert <jacob.lambert at amd.com>
Date: Mon, 18 Mar 2024 10:47:25 -0700
Subject: [PATCH 2/4] fix option name

---
 clang/lib/CodeGen/CodeGenAction.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
index 51f54d178672d1..a3ff5dc7d29e99 100644
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -359,7 +359,7 @@ void BackendConsumer::HandleTranslationUnit(ASTContext &C) {
   }
 
   // Link each LinkModule into our module.
-  if (!LinkBuiltinBitcodesPostopt && LinkInModules(getModule()))
+  if (!ClLinkBuiltinBitcodePostopt && LinkInModules(getModule()))
     return;
 
   for (auto &F : getModule()->functions()) {
@@ -1213,7 +1213,7 @@ void CodeGenAction::ExecuteAction() {
                          std::move(LinkModules), *VMContext, nullptr);
 
   // Link in each pending link module.
-  if (!LinkBuiltinBitcodesPostopt && Result.LinkInModules(&*TheModule))
+  if (!ClLinkBuiltinBitcodePostopt && Result.LinkInModules(&*TheModule))
     return;
 
   // PR44896: Force DiscardValueNames as false. DiscardValueNames cannot be

>From e2b6956227c40438b39d431333bcae9d27bdfd64 Mon Sep 17 00:00:00 2001
From: Jacob Lambert <jacob.lambert at amd.com>
Date: Mon, 18 Mar 2024 11:37:00 -0700
Subject: [PATCH 3/4] Fix analyses return and typo

---
 clang/lib/CodeGen/LinkInModulesPass.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/clang/lib/CodeGen/LinkInModulesPass.cpp b/clang/lib/CodeGen/LinkInModulesPass.cpp
index ce1c0ebe046a61..c3831aae13b647 100644
--- a/clang/lib/CodeGen/LinkInModulesPass.cpp
+++ b/clang/lib/CodeGen/LinkInModulesPass.cpp
@@ -29,7 +29,7 @@ PreservedAnalyses LinkInModulesPass::run(Module &M, ModuleAnalysisManager &AM) {
     return PreservedAnalyses::all();
 
   if (BC->LinkInModules(&M, ShouldLinkFiles))
-    report_fatal_error("Bitcode module re-linking failed, aborted!");
+    report_fatal_error("Bitcode module postopt linking failed, aborted!");
 
-  return PreservedAnalyses::all();
+  return PreservedAnalyses::none();
 }

>From 2238bf93af3ec7b3f0cbfd384148d96c9ee3039f Mon Sep 17 00:00:00 2001
From: Jacob Lambert <jacob.lambert at amd.com>
Date: Mon, 18 Mar 2024 11:38:31 -0700
Subject: [PATCH 4/4] Update comment

---
 clang/lib/CodeGen/BackendUtil.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index c5571eb15ce3a9..4031dc6b4db6cd 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -111,7 +111,7 @@ static cl::opt<bool> ClSanitizeOnOptimizerEarlyEP(
 
 extern cl::opt<InstrProfCorrelator::ProfCorrelatorKind> ProfileCorrelate;
 
-// Re-link builtin bitcodes after optimization
+// Link builtin bitcodes after optimization
 cl::opt<bool> ClLinkBuiltinBitcodePostopt(
     "link-builtin-bitcode-postopt", cl::Optional,
     cl::desc("Link builtin bitcodes after optimization."), cl::init(false));