[clang] a26cc75 - [clang][coverage] Fix "if constexpr" and "if consteval" coverage report (#77214)
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cfe-commits at lists.llvm.org
Wed Jan 10 02:01:27 PST 2024
Author: Hana Dusíková
Date: 2024-01-10T11:01:23+01:00
New Revision: a26cc759ae5a8018e2c328cf53173992340b995a
URL: https://github.com/llvm/llvm-project/commit/a26cc759ae5a8018e2c328cf53173992340b995a
DIFF: https://github.com/llvm/llvm-project/commit/a26cc759ae5a8018e2c328cf53173992340b995a.diff
LOG: [clang][coverage] Fix "if constexpr" and "if consteval" coverage report (#77214)
Replace the discarded statement by an empty compound statement so we can keep track of the
whole source range we need to skip in coverage
Fixes #54419
Added:
Modified:
clang/docs/ReleaseNotes.rst
clang/include/clang/AST/Stmt.h
clang/lib/CodeGen/CoverageMappingGen.cpp
clang/lib/Sema/TreeTransform.h
clang/test/CoverageMapping/if.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 20872f7ddb81e9..37f8bbc89d8949 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -705,6 +705,9 @@ Bug Fixes in This Version
- Fix assertion crash due to failed scope restoring caused by too-early VarDecl
invalidation by invalid initializer Expr.
Fixes (`#30908 <https://github.com/llvm/llvm-project/issues/30908>`_)
+- Clang now emits correct source location for code-coverage regions in `if constexpr`
+ and `if consteval` branches.
+ Fixes (`#54419 <https://github.com/llvm/llvm-project/issues/54419>`_)
Bug Fixes to Compiler Builtins
diff --git a/clang/include/clang/AST/Stmt.h b/clang/include/clang/AST/Stmt.h
index da7b37ce0e1211..e1fde24e647789 100644
--- a/clang/include/clang/AST/Stmt.h
+++ b/clang/include/clang/AST/Stmt.h
@@ -1631,8 +1631,10 @@ class CompoundStmt final
SourceLocation RB);
// Build an empty compound statement with a location.
- explicit CompoundStmt(SourceLocation Loc)
- : Stmt(CompoundStmtClass), LBraceLoc(Loc), RBraceLoc(Loc) {
+ explicit CompoundStmt(SourceLocation Loc) : CompoundStmt(Loc, Loc) {}
+
+ CompoundStmt(SourceLocation Loc, SourceLocation EndLoc)
+ : Stmt(CompoundStmtClass), LBraceLoc(Loc), RBraceLoc(EndLoc) {
CompoundStmtBits.NumStmts = 0;
CompoundStmtBits.HasFPFeatures = 0;
}
diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp
index bf227386a71b78..b245abd16c3f4a 100644
--- a/clang/lib/CodeGen/CoverageMappingGen.cpp
+++ b/clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -1712,7 +1712,11 @@ struct CounterCoverageMappingBuilder
extendRegion(S->getCond());
Counter ParentCount = getRegion().getCounter();
- Counter ThenCount = getRegionCounter(S);
+
+ // If this is "if !consteval" the then-branch will never be taken, we don't
+ // need to change counter
+ Counter ThenCount =
+ S->isNegatedConsteval() ? ParentCount : getRegionCounter(S);
if (!S->isConsteval()) {
// Emitting a counter for the condition makes it easier to interpret the
@@ -1729,7 +1733,12 @@ struct CounterCoverageMappingBuilder
extendRegion(S->getThen());
Counter OutCount = propagateCounts(ThenCount, S->getThen());
- Counter ElseCount = subtractCounters(ParentCount, ThenCount);
+ // If this is "if consteval" the else-branch will never be taken, we don't
+ // need to change counter
+ Counter ElseCount = S->isNonNegatedConsteval()
+ ? ParentCount
+ : subtractCounters(ParentCount, ThenCount);
+
if (const Stmt *Else = S->getElse()) {
bool ThenHasTerminateStmt = HasTerminateStmt;
HasTerminateStmt = false;
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index e7a6550b1c993c..1a1bc87d2b3203 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -7739,7 +7739,11 @@ TreeTransform<Derived>::TransformIfStmt(IfStmt *S) {
if (Then.isInvalid())
return StmtError();
} else {
- Then = new (getSema().Context) NullStmt(S->getThen()->getBeginLoc());
+ // Discarded branch is replaced with empty CompoundStmt so we can keep
+ // proper source location for start and end of original branch, so
+ // subsequent transformations like CoverageMapping work properly
+ Then = new (getSema().Context)
+ CompoundStmt(S->getThen()->getBeginLoc(), S->getThen()->getEndLoc());
}
// Transform the "else" branch.
@@ -7748,6 +7752,13 @@ TreeTransform<Derived>::TransformIfStmt(IfStmt *S) {
Else = getDerived().TransformStmt(S->getElse());
if (Else.isInvalid())
return StmtError();
+ } else if (S->getElse() && ConstexprConditionValue &&
+ *ConstexprConditionValue) {
+ // Same thing here as with <then> branch, we are discarding it, we can't
+ // replace it with NULL nor NullStmt as we need to keep for source location
+ // range, for CoverageMapping
+ Else = new (getSema().Context)
+ CompoundStmt(S->getElse()->getBeginLoc(), S->getElse()->getEndLoc());
}
if (!getDerived().AlwaysRebuild() &&
diff --git a/clang/test/CoverageMapping/if.cpp b/clang/test/CoverageMapping/if.cpp
index 65e3d62df79db4..92d560be01f3b7 100644
--- a/clang/test/CoverageMapping/if.cpp
+++ b/clang/test/CoverageMapping/if.cpp
@@ -23,19 +23,49 @@ void foo() { // CHECK-NEXT: Gap,File 0, [[@LINE+1]]:21 -> [[@
} // CHECK-NEXT: [[@LINE-2]]:9 -> [[@LINE-1]]:5 = #1
// CHECK-NEXT: [[@LINE-2]]:5 -> [[@LINE-2]]:8 = #1
-// FIXME: Do not generate coverage for discarded branches in if consteval and if constexpr statements
-constexpr int check_consteval(int i) {
- if consteval {
- i++;
- }
- if !consteval {
- i++;
- }
- if consteval {
- return 42;
- } else {
- return i;
- }
+// FIXME: Do not generate coverage for discarded branches in if constexpr
+// CHECK-LABEL: _Z30check_constexpr_true_with_elsei:
+int check_constexpr_true_with_else(int i) { // CHECK-NEXT: [[@LINE]]:{{[0-9]+}} -> {{[0-9]+}}:2 = #0
+ // CHECK-NEXT: [[@LINE+2]]:16 -> [[@LINE+2]]:20 = #0
+ // CHECK-NEXT: Branch,File 0, [[@LINE+1]]:16 -> [[@LINE+1]]:20 = 0, 0
+ if constexpr(true) { // CHECK-NEXT: Gap,File 0, [[@LINE]]:21 -> [[@LINE]]:22 = #1
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:22 -> [[@LINE+1]]:4 = #1
+ } else { // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE]]:10 = (#0 - #1)
+ i *= 5; // CHECK-NEXT: [[@LINE-1]]:10 -> [[@LINE+1]]:4 = (#0 - #1)
+ }
+ return i;
+}
+
+// CHECK-LABEL: _Z33check_constexpr_true_without_elsei:
+int check_constexpr_true_without_else(int i) { // CHECK-NEXT: [[@LINE]]:{{[0-9]+}} -> {{[0-9]+}}:2 = #0
+ // CHECK-NEXT: [[@LINE+2]]:16 -> [[@LINE+2]]:20 = #0
+ // CHECK-NEXT: Branch,File 0, [[@LINE+1]]:16 -> [[@LINE+1]]:20 = 0, 0
+ if constexpr(true) { // CHECK-NEXT: Gap,File 0, [[@LINE]]:21 -> [[@LINE]]:22 = #1
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:22 -> [[@LINE+1]]:4 = #1
+ }
+ return i;
+}
+
+// CHECK-LABEL: _Z31check_constexpr_false_with_elsei:
+int check_constexpr_false_with_else(int i) { // CHECK-NEXT: [[@LINE]]:{{[0-9]+}} -> {{[0-9]+}}:2 = #0
+ // CHECK-NEXT: [[@LINE+2]]:16 -> [[@LINE+2]]:21 = #0
+ // CHECK-NEXT: Branch,File 0, [[@LINE+1]]:16 -> [[@LINE+1]]:21 = 0, 0
+ if constexpr(false) { // CHECK-NEXT: Gap,File 0, [[@LINE]]:22 -> [[@LINE]]:23 = #1
+ i *= 3; // CHECK-NEXT: File 0, [[@LINE-1]]:23 -> [[@LINE+1]]:4 = #1
+ } else { // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE]]:10 = (#0 - #1)
+ i *= 5; // CHECK-NEXT: File 0, [[@LINE-1]]:10 -> [[@LINE+1]]:4 = (#0 - #1)
+ }
+ return i;
+}
+
+// CHECK-LABEL: _Z34check_constexpr_false_without_elsei:
+int check_constexpr_false_without_else(int i) { // CHECK-NEXT: [[@LINE]]:{{[0-9]+}} -> {{[0-9]+}}:2 = #0
+ // CHECK-NEXT: [[@LINE+2]]:16 -> [[@LINE+2]]:21 = #0
+ // CHECK-NEXT: Branch,File 0, [[@LINE+1]]:16 -> [[@LINE+1]]:21 = 0, 0
+ if constexpr(false) { // CHECK-NEXT: Gap,File 0, [[@LINE]]:22 -> [[@LINE]]:23 = #1
+ i *= 3; // CHECK-NEXT: File 0, [[@LINE-1]]:23 -> [[@LINE+1]]:4 = #1
+ }
+ return i;
}
// CHECK-LABEL: main:
@@ -75,10 +105,6 @@ int main() { // CHECK: File 0, [[@LINE]]:12 -> {{[0-9]+}}:2 =
// CHECK-NEXT: File 0, [[@LINE+1]]:14 -> [[@LINE+1]]:20 = #6
i = i == 0?i + 12:i + 10; // CHECK-NEXT: File 0, [[@LINE]]:21 -> [[@LINE]]:27 = (#0 - #6)
- // GH-57377
- constexpr int c_i = check_consteval(0);
- check_consteval(i);
-
// GH-45481
S s;
s.the_prop = 0? 1 : 2; // CHECK-NEXT: File 0, [[@LINE]]:16 -> [[@LINE]]:17 = #0
@@ -98,3 +124,51 @@ int main() { // CHECK: File 0, [[@LINE]]:12 -> {{[0-9]+}}:2 =
void ternary() {
true ? FOO : FOO; // CHECK-NOT: Gap,{{.*}}, [[@LINE]]:8 ->
}
+
+// GH-57377
+// CHECK-LABEL: _Z40check_consteval_with_else_discarded_theni:
+// FIXME: Do not generate coverage for discarded <then> branch in if consteval
+constexpr int check_consteval_with_else_discarded_then(int i) { // CHECK-NEXT: [[@LINE]]:{{[0-9]+}} -> {{[0-9]+}}:2 = #0
+ if consteval {
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:16 -> [[@LINE+1]]:4 = #1
+ } else { // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE]]:10 = #0
+ i *= 5; // CHECK-NEXT: [[@LINE-1]]:10 -> [[@LINE+1]]:4 = #0
+ }
+ return i; // CHECK-NEXT: [[@LINE]]:3 -> [[@LINE]]:11 = (#0 + #1)
+}
+
+// CHECK-LABEL: _Z43check_notconsteval_with_else_discarded_elsei:
+// FIXME: Do not generate coverage for discarded <else> branch in if consteval
+constexpr int check_notconsteval_with_else_discarded_else(int i) { // CHECK-NEXT: [[@LINE]]:{{[0-9]+}} -> {{[0-9]+}}:2 = #0
+ if !consteval {
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:17 -> [[@LINE+1]]:4 = #0
+ } else { // CHECK-NEXT: Gap,File 0, [[@LINE]]:4 -> [[@LINE]]:10 = 0
+ i *= 5; // CHECK-NEXT: [[@LINE-1]]:10 -> [[@LINE+1]]:4 = 0
+ }
+ return i;
+}
+
+// CHECK-LABEL: _Z32check_consteval_branch_discardedi:
+// FIXME: Do not generate coverage for discarded <then> branch in if consteval
+constexpr int check_consteval_branch_discarded(int i) { // CHECK-NEXT: [[@LINE]]:{{[0-9]+}} -> {{[0-9]+}}:2 = #0
+ if consteval {
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:16 -> [[@LINE+1]]:4 = #1
+ }
+ return i; // CHECK-NEXT: [[@LINE]]:3 -> [[@LINE]]:11 = (#0 + #1)
+}
+
+// CHECK-LABEL: _Z30check_notconsteval_branch_kepti:
+constexpr int check_notconsteval_branch_kept(int i) { // CHECK-NEXT: [[@LINE]]:{{[0-9]+}} -> {{[0-9]+}}:2 = #0
+ if !consteval {
+ i *= 3; // CHECK-NEXT: [[@LINE-1]]:17 -> [[@LINE+1]]:4 = #0
+ }
+ return i;
+}
+
+int instantiate_consteval(int i) {
+ i *= check_consteval_with_else_discarded_then(i);
+ i *= check_notconsteval_with_else_discarded_else(i);
+ i *= check_consteval_branch_discarded(i);
+ i *= check_notconsteval_branch_kept(i);
+ return i;
+}
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