[Clang] Propagate target-features if compatible when using mlink-builtin-bitcode

Buitlins from AMD's device-libs are compiled without specifying a
target-cpu, which results in builtins without the target-features
attribute set.

Before this patch, when linking this builtins with -mlink-builtin-bitcode
the target-features were not propagated in the incoming builtins.

With this patch, the default target features are propagated
if they are compatible with the target-features in the incoming builtin.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D159206

Author: jmmartinez

clang/lib/CodeGen/CGCall.cpp

@@ -2001,6 +2001,54 @@ static void getTrivialDefaultFunctionAttributes(
   }
 }
 
+static void
+overrideFunctionFeaturesWithTargetFeatures(llvm::AttrBuilder &FuncAttr,
+                                           const llvm::Function &F,
+                                           const TargetOptions &TargetOpts) {
+  auto FFeatures = F.getFnAttribute("target-features");
+
+  llvm::StringSet<> IncompatibleFeatureNames;
+  SmallVector<StringRef> MergedFeatures;
+  MergedFeatures.reserve(TargetOpts.Features.size());
+
+  if (FFeatures.isValid()) {
+    const auto &TFeatures = TargetOpts.FeatureMap;
+    for (StringRef Feature : llvm::split(FFeatures.getValueAsString(), ',')) {
+      if (Feature.empty())
+        continue;
+
+      bool EnabledForFunc = Feature.starts_with("+");
+      assert(EnabledForFunc || Feature.starts_with("-"));
+
+      StringRef Name = Feature.drop_front(1);
+      auto TEntry = TFeatures.find(Name);
+
+      // Preserves features that are incompatible (either set to something
+      // different or missing) from the target features
+      bool MissingFromTarget = TEntry == TFeatures.end();
+      bool EnabledForTarget = !MissingFromTarget && TEntry->second;
+      bool Incompatible = EnabledForTarget != EnabledForFunc;
+      if (MissingFromTarget || Incompatible) {
+        MergedFeatures.push_back(Feature);
+        if (Incompatible)
+          IncompatibleFeatureNames.insert(Name);
+      }
+    }
+  }
+
+  for (StringRef Feature : TargetOpts.Features) {
+    if (Feature.empty())
+      continue;
+    StringRef Name = Feature.drop_front(1);
+    if (IncompatibleFeatureNames.contains(Name))
+      continue;
+    MergedFeatures.push_back(Feature);
+  }
+
+  if (!MergedFeatures.empty())
+    FuncAttr.addAttribute("target-features", llvm::join(MergedFeatures, ","));
+}
+
 void CodeGen::mergeDefaultFunctionDefinitionAttributes(
     llvm::Function &F, const CodeGenOptions &CodeGenOpts,
     const LangOptions &LangOpts, const TargetOptions &TargetOpts,
@@ -2058,6 +2106,9 @@ void CodeGen::mergeDefaultFunctionDefinitionAttributes(
 
   F.removeFnAttrs(AttrsToRemove);
   addDenormalModeAttrs(Merged, MergedF32, FuncAttrs);
+
+  overrideFunctionFeaturesWithTargetFeatures(FuncAttrs, F, TargetOpts);
+
   F.addFnAttrs(FuncAttrs);
 }
 

clang/test/CodeGen/link-builtin-bitcode.c

@@ -1,42 +1,49 @@
-// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --check-attributes --check-globals --include-generated-funcs --version 2
+// Build two version of the bitcode library, one with a target-cpu set and one without
 // RUN: %clang_cc1 -triple amdgcn-- -target-cpu gfx803 -DBITCODE -emit-llvm-bc -o %t-lib.bc %s
+// RUN: %clang_cc1 -triple amdgcn-- -DBITCODE -emit-llvm-bc -o %t-lib.no-cpu.bc %s
+
 // RUN: %clang_cc1 -triple amdgcn-- -target-cpu gfx90a -emit-llvm-bc -o %t.bc %s
 // RUN: %clang_cc1 -triple amdgcn-- -target-cpu gfx90a -emit-llvm \
 // RUN:   -mlink-builtin-bitcode %t-lib.bc -o - %t.bc | FileCheck %s
 
+// RUN: %clang_cc1 -triple amdgcn-- -target-cpu gfx90a -emit-llvm-bc -o %t.bc %s
+// RUN: %clang_cc1 -triple amdgcn-- -target-cpu gfx90a -emit-llvm \
+// RUN:   -mlink-builtin-bitcode %t-lib.no-cpu.bc -o - %t.bc | FileCheck %s
+
 #ifdef BITCODE
-int foo(void) { return 42; }
+int no_attr(void) { return 42; }
+int __attribute__((target("gfx8-insts"))) attr_in_target(void) { return 42; }
+int __attribute__((target("extended-image-insts"))) attr_not_in_target(void) { return 42; }
+int __attribute__((target("no-gfx9-insts"))) attr_incompatible(void) { return 42; }
 int x = 12;
 #endif
 
-extern int foo(void);
+extern int no_attr(void);
+extern int attr_in_target(void);
+extern int attr_not_in_target(void);
+extern int attr_incompatible(void);
 extern int x;
 
-int bar() { return foo() + x; }
-//.
+int bar() { return no_attr() + attr_in_target() + attr_not_in_target() + attr_incompatible() + x; }
+
 // CHECK: @x = internal addrspace(1) global i32 12, align 4
-//.
-// CHECK: Function Attrs: noinline nounwind optnone
+
 // CHECK-LABEL: define dso_local i32 @bar
-// CHECK-SAME: () #[[ATTR0:[0-9]+]] {
-// CHECK-NEXT:  entry:
-// CHECK-NEXT:    [[RETVAL:%.*]] = alloca i32, align 4, addrspace(5)
-// CHECK-NEXT:    [[RETVAL_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[RETVAL]] to ptr
-// CHECK-NEXT:    [[CALL:%.*]] = call i32 @foo()
-// CHECK-NEXT:    [[TMP0:%.*]] = load i32, ptr addrspacecast (ptr addrspace(1) @x to ptr), align 4
-// CHECK-NEXT:    [[ADD:%.*]] = add nsw i32 [[CALL]], [[TMP0]]
-// CHECK-NEXT:    ret i32 [[ADD]]
+// CHECK-SAME: () #[[ATTR_BAR:[0-9]+]] {
 //
-//
-// CHECK: Function Attrs: convergent noinline nounwind optnone
-// CHECK-LABEL: define internal i32 @foo
-// CHECK-SAME: () #[[ATTR1:[0-9]+]] {
-// CHECK-NEXT:  entry:
-// CHECK-NEXT:    [[RETVAL:%.*]] = alloca i32, align 4, addrspace(5)
-// CHECK-NEXT:    [[RETVAL_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[RETVAL]] to ptr
-// CHECK-NEXT:    ret i32 42
-//
-//.
-// CHECK: attributes #0 = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="gfx90a" "target-features"="+16-bit-insts,+atomic-buffer-global-pk-add-f16-insts,+atomic-fadd-rtn-insts,+ci-insts,+dl-insts,+dot1-insts,+dot10-insts,+dot2-insts,+dot3-insts,+dot4-insts,+dot5-insts,+dot6-insts,+dot7-insts,+dpp,+gfx8-insts,+gfx9-insts,+gfx90a-insts,+mai-insts,+s-memrealtime,+s-memtime-inst,+wavefrontsize64" }
-// CHECK: attributes #1 = { convergent noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="gfx90a" "target-features"="+16-bit-insts,+ci-insts,+dpp,+gfx8-insts,+s-memrealtime,+s-memtime-inst,+wavefrontsize64" }
-//.
+// CHECK-LABEL: define internal i32 @no_attr
+// CHECK-SAME: () #[[ATTR_COMPATIBLE:[0-9]+]] {
+
+// CHECK-LABEL: define internal i32 @attr_in_target
+// CHECK-SAME: () #[[ATTR_COMPATIBLE:[0-9]+]] {
+
+// CHECK-LABEL: define internal i32 @attr_not_in_target
+// CHECK-SAME: () #[[ATTR_EXTEND:[0-9]+]] {
+
+// CHECK-LABEL: @attr_incompatible
+// CHECK-SAME: () #[[ATTR_INCOMPATIBLE:[0-9]+]] {
+
+// CHECK: attributes #[[ATTR_BAR]] = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="gfx90a" "target-features"="+16-bit-insts,+atomic-buffer-global-pk-add-f16-insts,+atomic-fadd-rtn-insts,+ci-insts,+dl-insts,+dot1-insts,+dot10-insts,+dot2-insts,+dot3-insts,+dot4-insts,+dot5-insts,+dot6-insts,+dot7-insts,+dpp,+gfx8-insts,+gfx9-insts,+gfx90a-insts,+mai-insts,+s-memrealtime,+s-memtime-inst,+wavefrontsize64" }
+// CHECK: attributes #[[ATTR_COMPATIBLE]] = { convergent noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="gfx90a" "target-features"="+16-bit-insts,+atomic-buffer-global-pk-add-f16-insts,+atomic-fadd-rtn-insts,+ci-insts,+dl-insts,+dot1-insts,+dot10-insts,+dot2-insts,+dot3-insts,+dot4-insts,+dot5-insts,+dot6-insts,+dot7-insts,+dpp,+gfx8-insts,+gfx9-insts,+gfx90a-insts,+gws,+image-insts,+mai-insts,+s-memrealtime,+s-memtime-inst,+wavefrontsize64" }
+// CHECK: attributes #[[ATTR_EXTEND]] = { convergent noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="gfx90a" "target-features"="+extended-image-insts,+16-bit-insts,+atomic-buffer-global-pk-add-f16-insts,+atomic-fadd-rtn-insts,+ci-insts,+dl-insts,+dot1-insts,+dot10-insts,+dot2-insts,+dot3-insts,+dot4-insts,+dot5-insts,+dot6-insts,+dot7-insts,+dpp,+gfx8-insts,+gfx9-insts,+gfx90a-insts,+gws,+image-insts,+mai-insts,+s-memrealtime,+s-memtime-inst,+wavefrontsize64" }
+// CHECK: attributes #[[ATTR_INCOMPATIBLE]] = { convergent noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="gfx90a" "target-features"="-gfx9-insts,+16-bit-insts,+atomic-buffer-global-pk-add-f16-insts,+atomic-fadd-rtn-insts,+ci-insts,+dl-insts,+dot1-insts,+dot10-insts,+dot2-insts,+dot3-insts,+dot4-insts,+dot5-insts,+dot6-insts,+dot7-insts,+dpp,+gfx8-insts,+gfx90a-insts,+gws,+image-insts,+mai-insts,+s-memrealtime,+s-memtime-inst,+wavefrontsize64" }

clang/test/CodeGenCUDA/link-builtin-bitcode-gpu-attrs-preserved.cu

@@ -31,7 +31,7 @@
 
 
 // CHECK: define {{.*}} i64 @do_intrin_stuff() #[[ATTR:[0-9]+]]
-// INTERNALIZE: attributes #[[ATTR]] = {{.*}} "target-cpu"="gfx{{.*}}" "target-features"="+gfx11-insts"
+// INTERNALIZE: attributes #[[ATTR]] = {{.*}} "target-cpu"="gfx{{.*}}" "target-features"="{{.*}}+gfx11-insts{{.*}}"
 // NOINTERNALIZE: attributes #[[ATTR]] = {{.*}} "target-features"="+gfx11-insts"
 
 #define __device__ __attribute__((device))