[clang] 524c640 - [clang][DebugInfo] Emit DISubprogram for extern functions with reserved names
Yonghong Song via cfe-commits
cfe-commits at lists.llvm.org
Fri Oct 28 08:08:09 PDT 2022
Author: Eduard Zingerman
Date: 2022-10-28T08:07:54-07:00
New Revision: 524c640090a8463305acbafd7606f1db3c1256e2
URL: https://github.com/llvm/llvm-project/commit/524c640090a8463305acbafd7606f1db3c1256e2
DIFF: https://github.com/llvm/llvm-project/commit/524c640090a8463305acbafd7606f1db3c1256e2.diff
LOG: [clang][DebugInfo] Emit DISubprogram for extern functions with reserved names
Callsite `DISubprogram` entries are not generated for:
- builtin functions;
- external functions with reserved names (e.g. names starting from "__").
This limitation was added by the commit [1] as a workaround for the
situation described in [2] that triggered the IR verifier error.
The goal of the present commit is to lift this limitation by adjusting
the IR verifier logic.
The logic behind [1] is to avoid the following situation:
- a `DISubprogram` is added for some builtin function;
- there is some location where this builtin is also emitted by a
transformation (w/o debug location);
- the `Verifier::visitCallBase` sees a call to a function with
`DISubprogram` but w/o debug location and emits an error.
Here is an updated example of such situation taken from [2]:
```
extern "C" int memcmp(void *, void *, long);
struct a { int b; int c; int d; };
struct e { int f[1000]; };
bool foo(e g, e &h) {
// DISubprogram for memcmp is created here when [1] is commented out
return memcmp(&g, &h, sizeof(e));
}
bool bar(a &g, a &h) {
// memcmp might be generated here by MergeICmps
return g.b == h.b && g.c == h.c && g.d == h.d;
}
```
This triggers the verifier error when:
- compiled for AArch64:
`clang++ -c -g -Oz -target aarch64-unknown-linux-android21 test.cpp`;
- [1] check is commented out.
Instead of forbidding generation of `DISubprogram` entries as in [1]
one can instead adjust the verifier to additionally check if callee
has a body. Functions w/o bodies cannot be inlined and thus verifier
warning is not necessary.
E.g. `llvm::InlineFunction` requires functions for which
`GlobalValue::isDeclaration() == false`.
[1] 568db780bb7267651a902da8e85bc59fc89aea70
[2] https://bugs.chromium.org/p/chromium/issues/detail?id=1022296
Differential Revision: https://reviews.llvm.org/D136041
Added:
Modified:
clang/lib/CodeGen/CGDebugInfo.cpp
clang/test/CodeGen/debug-info-extern-call.c
llvm/lib/IR/Verifier.cpp
llvm/test/Verifier/callsite-dbgloc.ll
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index aa02821aa971..4b56e155022a 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -4228,17 +4228,11 @@ void CGDebugInfo::EmitFuncDeclForCallSite(llvm::CallBase *CallOrInvoke,
if (Func->getSubprogram())
return;
- // Do not emit a declaration subprogram for a builtin, a function with nodebug
- // attribute, or if call site info isn't required. Also, elide declarations
- // for functions with reserved names, as call site-related features aren't
- // interesting in this case (& also, the compiler may emit calls to these
- // functions without debug locations, which makes the verifier complain).
- if (CalleeDecl->getBuiltinID() != 0 || CalleeDecl->hasAttr<NoDebugAttr>() ||
+ // Do not emit a declaration subprogram for a function with nodebug
+ // attribute, or if call site info isn't required.
+ if (CalleeDecl->hasAttr<NoDebugAttr>() ||
getCallSiteRelatedAttrs() == llvm::DINode::FlagZero)
return;
- if (CalleeDecl->isReserved(CGM.getLangOpts()) !=
- ReservedIdentifierStatus::NotReserved)
- return;
// If there is no DISubprogram attached to the function being called,
// create the one describing the function in order to have complete
diff --git a/clang/test/CodeGen/debug-info-extern-call.c b/clang/test/CodeGen/debug-info-extern-call.c
index fad52d0df0b3..0d18dc436040 100644
--- a/clang/test/CodeGen/debug-info-extern-call.c
+++ b/clang/test/CodeGen/debug-info-extern-call.c
@@ -29,8 +29,8 @@
// DECLS-FOR-EXTERN: [[FN1_TYPES]] = !{[[X_TYPE:![0-9]+]],
// DECLS-FOR-EXTERN: [[X_TYPE]] = !DIDerivedType(tag: DW_TAG_typedef, name: "x",
// DECLS-FOR-EXTERN-SAME: baseType: [[INT_TYPE]])
-// DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "memcmp"
-// DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "__some_reserved_name"
+// DECLS-FOR-EXTERN: !DISubprogram(name: "memcmp"
+// DECLS-FOR-EXTERN: !DISubprogram(name: "__some_reserved_name"
// NO-DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "fn1"
// NO-DECLS-FOR-EXTERN-NOT: !DISubprogram(name: "memcmp"
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 06f03164c19e..0614f206981a 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -3468,9 +3468,11 @@ void Verifier::visitCallBase(CallBase &Call) {
// Verify that each inlinable callsite of a debug-info-bearing function in a
// debug-info-bearing function has a debug location attached to it. Failure to
// do so causes assertion failures when the inliner sets up inline scope info
- // (Interposable functions are not inlinable).
+ // (Interposable functions are not inlinable, neither are functions without
+ // definitions.)
if (Call.getFunction()->getSubprogram() && Call.getCalledFunction() &&
!Call.getCalledFunction()->isInterposable() &&
+ !Call.getCalledFunction()->isDeclaration() &&
Call.getCalledFunction()->getSubprogram())
CheckDI(Call.getDebugLoc(),
"inlinable function call in a function with "
diff --git a/llvm/test/Verifier/callsite-dbgloc.ll b/llvm/test/Verifier/callsite-dbgloc.ll
index 4fdb55da4841..fef86f6bfb02 100644
--- a/llvm/test/Verifier/callsite-dbgloc.ll
+++ b/llvm/test/Verifier/callsite-dbgloc.ll
@@ -33,18 +33,24 @@ entry:
ret void, !dbg !22
}
-declare void @i(...) #1
+declare !dbg !23 void @i(...) #1
; Function Attrs: nounwind ssp uwtable
define void @g() #0 !dbg !11 {
entry:
; Manually removed !dbg.
; CHECK: inlinable function call in a function with debug info must have a !dbg location
+; CHECK: @h()
call void @h()
; CHECK-NOT: inlinable function call in a function with debug info must have a !dbg location
+; CHECK-NOT: @j()
call void @j()
; CHECK: inlinable function call in a function with debug info must have a !dbg location
+; CHECK: @k()
call void @k()
+; CHECK-NOT: inlinable function call in a function with debug info must have a !dbg location
+; CHECK-NOT: @i()
+ call void (...) @i()
ret void, !dbg !13
}
@@ -86,3 +92,6 @@ attributes #0 = { nounwind ssp uwtable }
!20 = distinct !DISubprogram(name: "k", scope: !1, file: !1, line: 6, type: !8, isLocal: false, isDefinition: true, scopeLine: 6, isOptimized: false, unit: !0, retainedNodes: !2)
!21 = !DILocation(line: 4, column: 12, scope: !20)
!22 = !DILocation(line: 4, column: 17, scope: !20)
+!23 = !DISubprogram(name: "i", scope: !1, file: !1, line: 1, type: !24, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+!24 = !DISubroutineType(types: !25)
+!25 = !{null}
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