https://github.com/andykaylor updated
https://github.com/llvm/llvm-project/pull/142862
>From 217f3a01f9ed161eb3afa3f7e6a594720e8a2840 Mon Sep 17 00:00:00 2001
From: Andy Kaylor <akay...@nvidia.com>
Date: Mon, 2 Jun 2025 17:11:55 -0700
Subject: [PATCH 1/3] [CIR] Defer emitting function definitions
This change implements deferring function definition emission until first
use.
---
clang/lib/CIR/CodeGen/CIRGenModule.cpp | 62 ++++++++++++++++++---
clang/test/CIR/CodeGen/deferred-fn-defs.cpp | 38 +++++++++++++
2 files changed, 91 insertions(+), 9 deletions(-)
create mode 100644 clang/test/CIR/CodeGen/deferred-fn-defs.cpp
diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
index eb291de8a3cc9..54c9fcf629e3d 100644
--- a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
@@ -213,13 +213,18 @@ CIRGenModule::getAddrOfGlobal(GlobalDecl gd,
ForDefinition_t isForDefinition) {
}
if (isa<CXXMethodDecl>(d)) {
- errorNYI(d->getSourceRange(), "getAddrOfGlobal: C++ method decl");
- return nullptr;
+ const CIRGenFunctionInfo &fi =
+ getTypes().arrangeCXXMethodDeclaration(cast<CXXMethodDecl>(d));
+ cir::FuncType ty = getTypes().getFunctionType(fi);
+ return getAddrOfFunction(gd, ty, /*ForVTable=*/false, /*DontDefer=*/false,
+ isForDefinition);
}
if (isa<FunctionDecl>(d)) {
- errorNYI(d->getSourceRange(), "getAddrOfGlobal: function decl");
- return nullptr;
+ const CIRGenFunctionInfo &fi = getTypes().arrangeGlobalDeclaration(gd);
+ cir::FuncType ty = getTypes().getFunctionType(fi);
+ return getAddrOfFunction(gd, ty, /*ForVTable=*/false, /*DontDefer=*/false,
+ isForDefinition);
}
return getAddrOfGlobalVar(cast<VarDecl>(d), /*ty=*/nullptr, isForDefinition)
@@ -1275,11 +1280,6 @@ bool CIRGenModule::mustBeEmitted(const ValueDecl
*global) {
vd->getType().isConstQualified())))
return true;
- // TODO(cir): We do want to defer function decls, but it's not implemented.
- assert(!cir::MissingFeatures::deferredFuncDecls());
- if (isa<FunctionDecl>(global))
- return true;
-
return getASTContext().DeclMustBeEmitted(global);
}
@@ -1523,6 +1523,50 @@ cir::FuncOp CIRGenModule::getOrCreateCIRFunction(
cir::FuncOp funcOp = createCIRFunction(
invalidLoc ? theModule->getLoc() : getLoc(funcDecl->getSourceRange()),
mangledName, mlir::cast<cir::FuncType>(funcType), funcDecl);
+
+ if (!dontDefer) {
+ // All MSVC dtors other than the base dtor are linkonce_odr and delegate to
+ // each other bottoming out wiht the base dtor. Therefore we emit non-base
+ // dtors on usage, even if there is no dtor definition in the TU.
+ if (isa_and_nonnull<CXXDestructorDecl>(d))
+ errorNYI(d->getSourceRange(), "getOrCreateCIRFunction: dtor");
+
+ // This is the first use or definition of a mangled name. If there is a
+ // deferred decl with this name, remember that we need to emit it at the
end
+ // of the file.
+ auto ddi = deferredDecls.find(mangledName);
+ if (ddi != deferredDecls.end()) {
+ // Move the potentially referenced deferred decl to the
+ // DeferredDeclsToEmit list, and remove it from DeferredDecls (since we
+ // don't need it anymore).
+ addDeferredDeclToEmit(ddi->second);
+ deferredDecls.erase(ddi);
+
+ // Otherwise, there are cases we have to worry about where we're using a
+ // declaration for which we must emit a definition but where we might not
+ // find a top-level definition.
+ // - member functions defined inline in their classes
+ // - friend functions defined inline in some class
+ // - special member functions with implicit definitions
+ // If we ever change our AST traversal to walk into class methods, this
+ // will be unnecessary.
+ //
+ // We also don't emit a definition for a function if it's going to be an
+ // entry in a vtable, unless it's already marked as used.
+ } else if (getLangOpts().CPlusPlus && d) {
+ // Look for a declaration that's lexically in a record.
+ for (const auto *fd = cast<FunctionDecl>(d)->getMostRecentDecl(); fd;
+ fd = fd->getPreviousDecl()) {
+ if (isa<CXXRecordDecl>(fd->getLexicalDeclContext())) {
+ if (fd->doesThisDeclarationHaveABody()) {
+ addDeferredDeclToEmit(gd.getWithDecl(fd));
+ break;
+ }
+ }
+ }
+ }
+ }
+
return funcOp;
}
diff --git a/clang/test/CIR/CodeGen/deferred-fn-defs.cpp
b/clang/test/CIR/CodeGen/deferred-fn-defs.cpp
new file mode 100644
index 0000000000000..e7088ba35eca7
--- /dev/null
+++ b/clang/test/CIR/CodeGen/deferred-fn-defs.cpp
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o
%t.cir
+// RUN: FileCheck --input-file=%t.cir %s --check-prefix=CIR
--implicit-check-not=externNotCalled \
+// RUN: --implicit-check-not=internalNotCalled
--implicit-check-not=inlineNotCalled
+
+extern int externCalled();
+extern int externNotCalled();
+
+namespace {
+ int internalCalled() { return 1; }
+ int internalNotCalled() { return 2; }
+}
+
+struct S {
+ int inlineCalled() { return 3; }
+ int inlineNotCalled() { return 4; }
+};
+
+void use() {
+ S s;
+ externCalled();
+ internalCalled();
+ s.inlineCalled();
+}
+
+// CIR: cir.func{{.*}} @_Z12externCalledv
+// This shouldn't have a body.
+// CIR-NOT: cir.return
+
+// CIR: cir.func{{.*}} @_ZN12_GLOBAL__N_114internalCalledEv
+// CIR: %[[ONE:.*]] = cir.const #cir.int<1>
+// CIR: cir.store %[[ONE]], %[[RET_ADDR:.*]]
+
+// CIR: cir.func{{.*}} @_ZN1S12inlineCalledEv
+// CIR: %[[THIS:.*]] = cir.alloca !cir.ptr<!rec_S>,
!cir.ptr<!cir.ptr<!rec_S>>, ["this", init]
+// CIR: %[[THREE:.*]] = cir.const #cir.int<3>
+// CIR: cir.store %[[THREE]], %[[RET_ADDR:.*]]
+
+// CIR: cir.func{{.*}} @_Z3usev()
>From 27bb7d528630bf298d3ea3315dbfd5e06949c71c Mon Sep 17 00:00:00 2001
From: Andy Kaylor <akay...@nvidia.com>
Date: Wed, 4 Jun 2025 16:56:44 -0700
Subject: [PATCH 2/3] Implement review suggestion
---
clang/lib/CIR/CodeGen/CIRGenModule.cpp | 82 ++++++++++++++------------
1 file changed, 44 insertions(+), 38 deletions(-)
diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
index 54c9fcf629e3d..0ad674344d1f1 100644
--- a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
@@ -1524,44 +1524,50 @@ cir::FuncOp CIRGenModule::getOrCreateCIRFunction(
invalidLoc ? theModule->getLoc() : getLoc(funcDecl->getSourceRange()),
mangledName, mlir::cast<cir::FuncType>(funcType), funcDecl);
- if (!dontDefer) {
- // All MSVC dtors other than the base dtor are linkonce_odr and delegate to
- // each other bottoming out wiht the base dtor. Therefore we emit non-base
- // dtors on usage, even if there is no dtor definition in the TU.
- if (isa_and_nonnull<CXXDestructorDecl>(d))
- errorNYI(d->getSourceRange(), "getOrCreateCIRFunction: dtor");
-
- // This is the first use or definition of a mangled name. If there is a
- // deferred decl with this name, remember that we need to emit it at the
end
- // of the file.
- auto ddi = deferredDecls.find(mangledName);
- if (ddi != deferredDecls.end()) {
- // Move the potentially referenced deferred decl to the
- // DeferredDeclsToEmit list, and remove it from DeferredDecls (since we
- // don't need it anymore).
- addDeferredDeclToEmit(ddi->second);
- deferredDecls.erase(ddi);
-
- // Otherwise, there are cases we have to worry about where we're using a
- // declaration for which we must emit a definition but where we might not
- // find a top-level definition.
- // - member functions defined inline in their classes
- // - friend functions defined inline in some class
- // - special member functions with implicit definitions
- // If we ever change our AST traversal to walk into class methods, this
- // will be unnecessary.
- //
- // We also don't emit a definition for a function if it's going to be an
- // entry in a vtable, unless it's already marked as used.
- } else if (getLangOpts().CPlusPlus && d) {
- // Look for a declaration that's lexically in a record.
- for (const auto *fd = cast<FunctionDecl>(d)->getMostRecentDecl(); fd;
- fd = fd->getPreviousDecl()) {
- if (isa<CXXRecordDecl>(fd->getLexicalDeclContext())) {
- if (fd->doesThisDeclarationHaveABody()) {
- addDeferredDeclToEmit(gd.getWithDecl(fd));
- break;
- }
+ // 'dontDefer' actually means don't move this to the deferredDeclsToEmit
list.
+ if (dontDefer) {
+ // TODO(cir): This assertion will need an additional condition when we
+ // support incomplete functions.
+ assert(funcOp.getFunctionType() == funcType);
+ return funcOp;
+ }
+
+ // All MSVC dtors other than the base dtor are linkonce_odr and delegate to
+ // each other bottoming out wiht the base dtor. Therefore we emit non-base
+ // dtors on usage, even if there is no dtor definition in the TU.
+ if (isa_and_nonnull<CXXDestructorDecl>(d))
+ errorNYI(d->getSourceRange(), "getOrCreateCIRFunction: dtor");
+
+ // This is the first use or definition of a mangled name. If there is a
+ // deferred decl with this name, remember that we need to emit it at the end
+ // of the file.
+ auto ddi = deferredDecls.find(mangledName);
+ if (ddi != deferredDecls.end()) {
+ // Move the potentially referenced deferred decl to the
+ // DeferredDeclsToEmit list, and remove it from DeferredDecls (since we
+ // don't need it anymore).
+ addDeferredDeclToEmit(ddi->second);
+ deferredDecls.erase(ddi);
+
+ // Otherwise, there are cases we have to worry about where we're using a
+ // declaration for which we must emit a definition but where we might not
+ // find a top-level definition.
+ // - member functions defined inline in their classes
+ // - friend functions defined inline in some class
+ // - special member functions with implicit definitions
+ // If we ever change our AST traversal to walk into class methods, this
+ // will be unnecessary.
+ //
+ // We also don't emit a definition for a function if it's going to be an
+ // entry in a vtable, unless it's already marked as used.
+ } else if (getLangOpts().CPlusPlus && d) {
+ // Look for a declaration that's lexically in a record.
+ for (const auto *fd = cast<FunctionDecl>(d)->getMostRecentDecl(); fd;
+ fd = fd->getPreviousDecl()) {
+ if (isa<CXXRecordDecl>(fd->getLexicalDeclContext())) {
+ if (fd->doesThisDeclarationHaveABody()) {
+ addDeferredDeclToEmit(gd.getWithDecl(fd));
+ break;
}
}
}
>From cc638daba965701f155fd01d9f5c3a52d5a1c2d4 Mon Sep 17 00:00:00 2001
From: Andy Kaylor <akay...@nvidia.com>
Date: Thu, 5 Jun 2025 10:09:05 -0700
Subject: [PATCH 3/3] Fix formatting
---
clang/lib/CIR/CodeGen/CIRGenModule.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
index 0ad674344d1f1..87e364197ce7e 100644
--- a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
@@ -1563,7 +1563,7 @@ cir::FuncOp CIRGenModule::getOrCreateCIRFunction(
} else if (getLangOpts().CPlusPlus && d) {
// Look for a declaration that's lexically in a record.
for (const auto *fd = cast<FunctionDecl>(d)->getMostRecentDecl(); fd;
- fd = fd->getPreviousDecl()) {
+ fd = fd->getPreviousDecl()) {
if (isa<CXXRecordDecl>(fd->getLexicalDeclContext())) {
if (fd->doesThisDeclarationHaveABody()) {
addDeferredDeclToEmit(gd.getWithDecl(fd));
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