[clang] [CIR] Add Support For Library Builtins (PR #143984)
Morris Hafner via cfe-commits
cfe-commits at lists.llvm.org
Thu Jun 12 16:08:28 PDT 2025
https://github.com/mmha updated https://github.com/llvm/llvm-project/pull/143984
>From c60378591a7d8d156306ff9c840aa319396c4f00 Mon Sep 17 00:00:00 2001
From: Morris Hafner <mhafner at nvidia.com>
Date: Fri, 13 Jun 2025 00:04:24 +0200
Subject: [PATCH 1/3] [CIR] Add Support For Library Builtins
This patch upstreams support for builtins that map to a standard library
function. Examples would be abort() and printf().
It also fixes a minor issue with the errorNYI for all remaining
unimplemented builtins using the mlir::Location instead of the clang AST
SourceLocation.
---
clang/include/clang/CIR/MissingFeatures.h | 1 +
clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp | 39 +++++++++++++++++++++--
clang/lib/CIR/CodeGen/CIRGenModule.h | 4 +++
clang/test/CIR/CodeGen/builtin_call.cpp | 18 +++++++++++
4 files changed, 60 insertions(+), 2 deletions(-)
diff --git a/clang/include/clang/CIR/MissingFeatures.h b/clang/include/clang/CIR/MissingFeatures.h
index 97b933657d742..9d518030a1aeb 100644
--- a/clang/include/clang/CIR/MissingFeatures.h
+++ b/clang/include/clang/CIR/MissingFeatures.h
@@ -230,6 +230,7 @@ struct MissingFeatures {
static bool attributeNoBuiltin() { return false; }
static bool thunks() { return false; }
static bool runCleanupsScope() { return false; }
+ static bool asmLabelAttr() { return false; }
// Missing types
static bool dataMemberType() { return false; }
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
index c59ac78210f81..963ba77db908e 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
@@ -20,10 +20,18 @@
#include "mlir/Support/LLVM.h"
#include "clang/AST/Expr.h"
#include "clang/AST/GlobalDecl.h"
+#include "clang/CIR/MissingFeatures.h"
#include "llvm/Support/ErrorHandling.h"
using namespace clang;
using namespace clang::CIRGen;
+using namespace llvm;
+
+static RValue emitLibraryCall(CIRGenFunction &cgf, const FunctionDecl *fd,
+ const CallExpr *e, mlir::Operation *calleeValue) {
+ CIRGenCallee callee = CIRGenCallee::forDirect(calleeValue, GlobalDecl(fd));
+ return cgf.emitCall(e->getCallee()->getType(), callee, e, ReturnValueSlot());
+}
RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
const CallExpr *e,
@@ -49,7 +57,34 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
}
}
- mlir::Location loc = getLoc(e->getExprLoc());
- cgm.errorNYI(loc, "non constant foldable builtin calls");
+ const FunctionDecl *fd = gd.getDecl()->getAsFunction();
+
+ // If this is an alias for a lib function (e.g. __builtin_sin), emit
+ // the call using the normal call path, but using the unmangled
+ // version of the function name.
+ if (getContext().BuiltinInfo.isLibFunction(builtinID))
+ return emitLibraryCall(*this, fd, e,
+ cgm.getBuiltinLibFunction(fd, builtinID));
+
+ cgm.errorNYI(e->getSourceRange(), "non constant foldable builtin calls");
return getUndefRValue(e->getType());
}
+
+/// Given a builtin id for a function like "__builtin_fabsf", return a Function*
+/// for "fabsf".
+cir::FuncOp CIRGenModule::getBuiltinLibFunction(const FunctionDecl *fd,
+ unsigned builtinID) {
+ assert(astContext.BuiltinInfo.isLibFunction(builtinID));
+
+ // Get the name, skip over the __builtin_ prefix (if necessary). We may have
+ // to build this up so provide a small stack buffer to handle the vast
+ // majority of names.
+ llvm::SmallString<64> name;
+
+ assert(!cir::MissingFeatures::asmLabelAttr());
+ name = astContext.BuiltinInfo.getName(builtinID).substr(10);
+
+ GlobalDecl d(fd);
+ mlir::Type type = convertType(fd->getType());
+ return getOrCreateCIRFunction(name, type, d, /*forVTable=*/false);
+}
diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.h b/clang/lib/CIR/CodeGen/CIRGenModule.h
index f76fd8e733642..2f4043a4e15e8 100644
--- a/clang/lib/CIR/CodeGen/CIRGenModule.h
+++ b/clang/lib/CIR/CodeGen/CIRGenModule.h
@@ -288,6 +288,10 @@ class CIRGenModule : public CIRGenTypeCache {
cir::FuncType funcType,
const clang::FunctionDecl *funcDecl);
+ /// Given a builtin id for a function like "__builtin_fabsf", return a
+ /// Function* for "fabsf".
+ cir::FuncOp getBuiltinLibFunction(const FunctionDecl *fd, unsigned builtinID);
+
mlir::IntegerAttr getSize(CharUnits size) {
return builder.getSizeFromCharUnits(size);
}
diff --git a/clang/test/CIR/CodeGen/builtin_call.cpp b/clang/test/CIR/CodeGen/builtin_call.cpp
index 2706ea7f8f857..322c13c8f081a 100644
--- a/clang/test/CIR/CodeGen/builtin_call.cpp
+++ b/clang/test/CIR/CodeGen/builtin_call.cpp
@@ -76,3 +76,21 @@ float constant_fp_builtin_single() {
// OGCG: define {{.*}}float @_Z26constant_fp_builtin_singlev()
// OGCG: ret float 0x3FB99999A0000000
// OGCG: }
+
+void library_builtins() {
+ __builtin_printf(nullptr);
+ __builtin_abort();
+}
+
+// CIR: cir.func @_Z16library_builtinsv() {
+// CIR: %[[NULL:.+]] = cir.const #cir.ptr<null> : !cir.ptr<!s8i>
+// CIR: cir.call @printf(%[[NULL]]) : (!cir.ptr<!s8i>) -> !s32i
+// CIR: cir.call @abort() : () -> ()
+
+// LLVM: define void @_Z16library_builtinsv()
+// LLVM: call i32 (ptr, ...) @printf(ptr null)
+// LLVM: call void @abort()
+
+// OGCG: define dso_local void @_Z16library_builtinsv()
+// OGCG: call i32 (ptr, ...) @printf(ptr noundef null)
+// OGCG: call void @abort()
>From 92c7c207d0cee4546415e2d24a578fad84650f3f Mon Sep 17 00:00:00 2001
From: Morris Hafner <mhafner at nvidia.com>
Date: Fri, 13 Jun 2025 00:16:35 +0200
Subject: [PATCH 2/3] Update NYI error message
---
clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
index 963ba77db908e..19fac00ab8736 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
@@ -66,7 +66,7 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
return emitLibraryCall(*this, fd, e,
cgm.getBuiltinLibFunction(fd, builtinID));
- cgm.errorNYI(e->getSourceRange(), "non constant foldable builtin calls");
+ cgm.errorNYI(e->getSourceRange(), "unimplemented builtin call");
return getUndefRValue(e->getType());
}
>From 26cdc629d685c227bc171dfb6068e5b1746533fe Mon Sep 17 00:00:00 2001
From: Morris Hafner <mhafner at nvidia.com>
Date: Fri, 13 Jun 2025 01:08:14 +0200
Subject: [PATCH 3/3] Add printf test cases
---
clang/test/CIR/CodeGen/builtin_printf.cpp | 63 +++++++++++++++++++++++
1 file changed, 63 insertions(+)
create mode 100644 clang/test/CIR/CodeGen/builtin_printf.cpp
diff --git a/clang/test/CIR/CodeGen/builtin_printf.cpp b/clang/test/CIR/CodeGen/builtin_printf.cpp
new file mode 100644
index 0000000000000..f8e01ab629bbe
--- /dev/null
+++ b/clang/test/CIR/CodeGen/builtin_printf.cpp
@@ -0,0 +1,63 @@
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s -check-prefix=CIR
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --input-file=%t-cir.ll %s -check-prefix=LLVM
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-linux-gnu -Wno-unused-value -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s -check-prefix=OGCG
+
+// CIR: cir.global "private" cir_private dsolocal @".str" = #cir.const_array<"%s\00" : !cir.array<!s8i x 3>> : !cir.array<!s8i x 3>
+// CIR: cir.global "private" cir_private dsolocal @".str.1" = #cir.const_array<"%s %d\0A\00" : !cir.array<!s8i x 7>> : !cir.array<!s8i x 7>
+// LLVM: @.str = private global [3 x i8] c"%s\00"
+// LLVM: @.str.1 = private global [7 x i8] c"%s %d\0A\00"
+// OGCG: @.str = private unnamed_addr constant [3 x i8] c"%s\00"
+// OGCG: @.str.1 = private unnamed_addr constant [7 x i8] c"%s %d\0A\00"
+
+void func(char const * const str, int i) {
+ __builtin_printf(nullptr);
+ __builtin_printf("%s", str);
+ __builtin_printf("%s %d\n", str, i);
+}
+
+// CIR: cir.func @_Z4funcPKci(%[[arg0:.+]]: !cir.ptr<!s8i>{{.*}}, %[[arg1:.+]]: !s32i{{.*}}) {
+// CIR: %[[str_ptr:.+]] = cir.alloca !cir.ptr<!s8i>, !cir.ptr<!cir.ptr<!s8i>>, ["str", init, const]
+// CIR: %[[i_ptr:.+]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["i", init]
+// CIR: cir.store %[[arg0]], %[[str_ptr]] : !cir.ptr<!s8i>, !cir.ptr<!cir.ptr<!s8i>>
+// CIR: cir.store %[[arg1]], %[[i_ptr]] : !s32i, !cir.ptr<!s32i>
+// CIR: %[[null_ptr:.+]] = cir.const #cir.ptr<null> : !cir.ptr<!s8i>
+// CIR: %[[printf_result1:.+]] = cir.call @printf(%[[null_ptr]]) : (!cir.ptr<!s8i>) -> !s32i
+// CIR: %[[str_fmt_global:.+]] = cir.get_global @".str" : !cir.ptr<!cir.array<!s8i x 3>>
+// CIR: %[[str_fmt_ptr:.+]] = cir.cast(array_to_ptrdecay, %[[str_fmt_global]] : !cir.ptr<!cir.array<!s8i x 3>>), !cir.ptr<!s8i>
+// CIR: %[[str_val:.+]] = cir.load{{.*}} %[[str_ptr]] : !cir.ptr<!cir.ptr<!s8i>>, !cir.ptr<!s8i>
+// CIR: %[[printf_result2:.+]] = cir.call @printf(%[[str_fmt_ptr]], %[[str_val]]) : (!cir.ptr<!s8i>, !cir.ptr<!s8i>) -> !s32i
+// CIR: %[[full_fmt_global:.+]] = cir.get_global @".str.1" : !cir.ptr<!cir.array<!s8i x 7>>
+// CIR: %[[full_fmt_ptr:.+]] = cir.cast(array_to_ptrdecay, %[[full_fmt_global]] : !cir.ptr<!cir.array<!s8i x 7>>), !cir.ptr<!s8i>
+// CIR: %[[str_val2:.+]] = cir.load{{.*}} %[[str_ptr]] : !cir.ptr<!cir.ptr<!s8i>>, !cir.ptr<!s8i>
+// CIR: %[[i_val:.+]] = cir.load{{.*}} %[[i_ptr]] : !cir.ptr<!s32i>, !s32i
+// CIR: %[[printf_result3:.+]] = cir.call @printf(%[[full_fmt_ptr]], %[[str_val2]], %[[i_val]]) : (!cir.ptr<!s8i>, !cir.ptr<!s8i>, !s32i) -> !s32i
+// CIR: cir.return
+
+// LLVM: define void @_Z4funcPKci(ptr %[[arg0:.+]], i32 %[[arg1:.+]])
+// LLVM: %[[str_ptr:.+]] = alloca ptr
+// LLVM: %[[i_ptr:.+]] = alloca i32
+// LLVM: store ptr %[[arg0]], ptr %[[str_ptr]]{{.*}}
+// LLVM: store i32 %[[arg1]], ptr %[[i_ptr]]{{.*}}
+// LLVM: %[[printf_result1:.+]] = call i32 (ptr, ...) @printf(ptr null)
+// LLVM: %[[str_val:.+]] = load ptr, ptr %[[str_ptr]]{{.*}}
+// LLVM: %[[printf_result2:.+]] = call i32 (ptr, ...) @printf(ptr @.str, ptr %[[str_val]])
+// LLVM: %[[str_val2:.+]] = load ptr, ptr %[[str_ptr]]{{.*}}
+// LLVM: %[[i_val:.+]] = load i32, ptr %[[i_ptr]]{{.*}}
+// LLVM: %[[printf_result3:.+]] = call i32 (ptr, ...) @printf(ptr @.str.1, ptr %[[str_val2]], i32 %[[i_val]])
+// LLVM: ret void
+
+// OGCG: define dso_local void @_Z4funcPKci(ptr noundef %[[arg0:.+]], i32 noundef %[[arg1:.+]])
+// OGCG: %[[str_ptr:.+]] = alloca ptr
+// OGCG: %[[i_ptr:.+]] = alloca i32
+// OGCG: store ptr %[[arg0]], ptr %[[str_ptr]]{{.*}}
+// OGCG: store i32 %[[arg1]], ptr %[[i_ptr]]{{.*}}
+// OGCG: %[[printf_result1:.+]] = call i32 (ptr, ...) @printf(ptr noundef null)
+// OGCG: %[[str_val:.+]] = load ptr, ptr %[[str_ptr]]{{.*}}
+// OGCG: %[[printf_result2:.+]] = call i32 (ptr, ...) @printf(ptr noundef @.str, ptr noundef %[[str_val]])
+// OGCG: %[[str_val2:.+]] = load ptr, ptr %[[str_ptr]]{{.*}}
+// OGCG: %[[i_val:.+]] = load i32, ptr %[[i_ptr]]{{.*}}
+// OGCG: %[[printf_result3:.+]] = call i32 (ptr, ...) @printf(ptr noundef @.str.1, ptr noundef %[[str_val2]], i32 noundef %[[i_val]])
+// OGCG: ret void
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