[KeyInstr][Clang] Copy ctor/assignment operator source atoms

[OCHyams]

No description provided.

[llvmbot]

@llvm/pr-subscribers-clang
@llvm/pr-subscribers-clang-codegen

@llvm/pr-subscribers-debuginfo

Author: Orlando Cazalet-Hyams (OCHyams)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/144346.diff

3 Files Affected:

• (modified) clang/lib/CodeGen/CGClass.cpp (+4-1)
• (added) clang/test/DebugInfo/KeyInstructions/init-member-memcopyable-2.cpp (+36)
• (added) clang/test/DebugInfo/KeyInstructions/init-member-memcopyable.cpp (+38)

diff --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp
index 13792c1042046..c78267857bc9e 100644
--- a/clang/lib/CodeGen/CGClass.cpp
+++ b/clang/lib/CodeGen/CGClass.cpp
@@ -1000,7 +1000,8 @@ namespace {
     void emitMemcpyIR(Address DestPtr, Address SrcPtr, CharUnits Size) {
       DestPtr = DestPtr.withElementType(CGF.Int8Ty);
       SrcPtr = SrcPtr.withElementType(CGF.Int8Ty);
-      CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, Size.getQuantity());
+      auto *I = CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, Size.getQuantity());
+      CGF.addInstToCurrentSourceAtom(I, nullptr);
     }
 
     void addInitialField(FieldDecl *F) {
@@ -1341,6 +1342,8 @@ void CodeGenFunction::EmitCtorPrologue(const CXXConstructorDecl *CD,
     ApplyAtomGroup Grp(getDebugInfo());
     CM.addMemberInitializer(Member);
   }
+
+  ApplyAtomGroup Grp(getDebugInfo());
   CM.finish();
 }
 
diff --git a/clang/test/DebugInfo/KeyInstructions/init-member-memcopyable-2.cpp b/clang/test/DebugInfo/KeyInstructions/init-member-memcopyable-2.cpp
new file mode 100644
index 0000000000000..3df5dc357169e
--- /dev/null
+++ b/clang/test/DebugInfo/KeyInstructions/init-member-memcopyable-2.cpp
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -gkey-instructions %s -gno-column-info -debug-info-kind=line-tables-only -emit-llvm -o - \
+// RUN: | FileCheck %s
+
+// g::h and i can be memcpy'd, check the assignment gets Key Instructions metadata.
+
+struct e {
+  e(e &);
+};
+
+struct g {
+  e f;
+  int h;
+  int i;
+};
+
+// CHECK: define{{.*}}void @_ZN1gC2ERS_
+// CHECK-NEXT: entry:
+// CHECK-NEXT: %this.addr = alloca ptr, align 8
+// CHECK-NEXT: %.addr = alloca ptr, align 8
+// CHECK-NEXT: store ptr %this, ptr %this.addr, align 8
+// CHECK-NEXT: store ptr %0, ptr %.addr, align 8
+// CHECK-NEXT: %this1 = load ptr, ptr %this.addr, align 8
+// CHECK-NEXT: %1 = load ptr, ptr %.addr, align 8
+// CHECK-NEXT: call void @_ZN1eC1ERS_
+// CHECK-NEXT: %h = getelementptr inbounds nuw %struct.g, ptr %this1, i32 0, i32 1
+// CHECK-NEXT: %2 = load ptr, ptr %.addr, align 8
+// CHECK-NEXT: %h2 = getelementptr inbounds nuw %struct.g, ptr %2, i32 0, i32 1
+// CHECK-NEXT: call void @llvm.memcpy{{.*}}(ptr align 4 %h, ptr align 4 %h2, i64 8, i1 false), !dbg [[G1R1:!.*]]
+// CHECK-NEXT: ret void, !dbg
+
+// CHECK: [[G1R1]] = !DILocation(line: 10, scope: ![[#]], atomGroup: 1, atomRank: 1)
+
+[[gnu::nodebug]]
+void fun(g *x) {
+  g y = g(*x);
+}
diff --git a/clang/test/DebugInfo/KeyInstructions/init-member-memcopyable.cpp b/clang/test/DebugInfo/KeyInstructions/init-member-memcopyable.cpp
new file mode 100644
index 0000000000000..b73683c660b4e
--- /dev/null
+++ b/clang/test/DebugInfo/KeyInstructions/init-member-memcopyable.cpp
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu -gkey-instructions %s -gno-column-info -debug-info-kind=line-tables-only -emit-llvm -o - \
+// RUN: | FileCheck %s
+
+// g::h can be memcpy'd (in this case emitted as load/stored), check the
+// assignment gets Key Instructions metadata.
+
+struct e {
+  e(e &);
+};
+
+struct g {
+  e f;
+  int h;
+};
+
+// CHECK: define{{.*}}void @_ZN1gC2ERS_
+// CHECK-NEXT: entry:
+// CHECK-NEXT: %this.addr = alloca ptr, align 8
+// CHECK-NEXT: %.addr = alloca ptr, align 8
+// CHECK-NEXT: store ptr %this, ptr %this.addr, align 8
+// CHECK-NEXT: store ptr %0, ptr %.addr, align 8
+// CHECK-NEXT: %this1 = load ptr, ptr %this.addr, align 8
+// CHECK-NEXT: %1 = load ptr, ptr %.addr, align 8
+// CHECK-NEXT: call void @_ZN1eC1ERS_
+// CHECK-NEXT: %h = getelementptr inbounds nuw %struct.g, ptr %this1, i32 0, i32 1
+// CHECK-NEXT: %2 = load ptr, ptr %.addr, align 8
+// CHECK-NEXT: %h2 = getelementptr inbounds nuw %struct.g, ptr %2, i32 0, i32 1
+// CHECK-NEXT: %3 = load i32, ptr %h2, align 4, !dbg [[G1R2:!.*]]
+// CHECK-NEXT: store i32 %3, ptr %h, align 4, !dbg [[G1R1:!.*]]
+// CHECK-NEXT: ret void, !dbg
+
+// CHECK: [[G1R2]] = !DILocation(line: 11, scope: ![[#]], atomGroup: 1, atomRank: 2)
+// CHECK: [[G1R1]] = !DILocation(line: 11, scope: ![[#]], atomGroup: 1, atomRank: 1)
+
+[[gnu::nodebug]]
+void fun(g *x) {
+  g y = g(*x);
+}

[jmorse]

From the context, it feels like clang is going to try turning groups of initializers into memcpys, is that right? If so, does that affect the desired stepping behaviour, i.e. would multiple assignments be grouped into one memcpy? I suppose it's not majorly important (but worth having test coverage)

... ah that's what you've done, right. Leaving my comment for posterity. LGTM.

[jmorse]

This'll trip on Windows machines IMO, there's a %clang_cc1 macro that ensures you're targetting an Itanium ABI I think?