[clang] [compiler-rt] [Coverage] Fix region creation after try statements (PR #133463)
Justin Cady via llvm-commits
llvm-commits at lists.llvm.org
Fri Mar 28 09:22:00 PDT 2025
https://github.com/justincady created https://github.com/llvm/llvm-project/pull/133463
In cases where a terminating statement exists within the try or catch
block the coverage mapping can be incorrect. Coverage reports display
lines following the last catch block as uncovered, when the lines have
been executed.
This change adjusts the mapping such that an extra region is only
created after a try block if the try itself contains the terminating
statement.
The testing validates coverage more broadly than the above to ensure
other mapping around exception handling does not regress with this
change.
>From 6f79ddba80fa391a8c1ddbd3b2217f2e5a9ce21b Mon Sep 17 00:00:00 2001
From: Justin Cady <desk at justincady.com>
Date: Fri, 28 Mar 2025 12:07:44 -0400
Subject: [PATCH] [Coverage] Fix region creation after try statements
In cases where a terminating statement exists within the try or catch
block the coverage mapping can be incorrect. Coverage reports display
lines following the last catch block as uncovered, when the lines have
been executed.
This change adjusts the mapping such that an extra region is only
created after a try block if the try itself contains the terminating
statement.
The testing validates coverage more broadly than the above to ensure
other mapping around exception handling does not regress with this
change.
---
clang/lib/CodeGen/CoverageMappingGen.cpp | 10 +-
clang/test/CoverageMapping/trycatch.cpp | 4 +-
.../test/profile/Linux/coverage-exception.cpp | 142 ++++++++++++++++++
3 files changed, 152 insertions(+), 4 deletions(-)
create mode 100644 compiler-rt/test/profile/Linux/coverage-exception.cpp
diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp
index 73811d15979d5..f3b819bcf3b20 100644
--- a/clang/lib/CodeGen/CoverageMappingGen.cpp
+++ b/clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -2123,11 +2123,17 @@ struct CounterCoverageMappingBuilder
Counter ParentCount = getRegion().getCounter();
propagateCounts(ParentCount, S->getTryBlock());
+ bool TryHasTerminateStmt = HasTerminateStmt;
+
for (unsigned I = 0, E = S->getNumHandlers(); I < E; ++I)
Visit(S->getHandler(I));
- Counter ExitCount = getRegionCounter(S);
- pushRegion(ExitCount);
+ if (TryHasTerminateStmt) {
+ Counter ExitCount = getRegionCounter(S);
+ pushRegion(ExitCount);
+ }
+
+ HasTerminateStmt = TryHasTerminateStmt;
}
void VisitCXXCatchStmt(const CXXCatchStmt *S) {
diff --git a/clang/test/CoverageMapping/trycatch.cpp b/clang/test/CoverageMapping/trycatch.cpp
index 89fae8af9b720..e5d2482c6b151 100644
--- a/clang/test/CoverageMapping/trycatch.cpp
+++ b/clang/test/CoverageMapping/trycatch.cpp
@@ -33,5 +33,5 @@ int main() { // CHECK-NEXT: File 0, [[@LINE]]:12 -> [[@
catch(const Warning &w) { // CHECK-NEXT: File 0, [[@LINE]]:27 -> [[@LINE+2]]:4 = #4
j = 0;
}
- return 0; // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE]]:11 = #1
-}
+ return 0; // CHECK-NOT: File 0
+} // CHECK-NOT: File 0
diff --git a/compiler-rt/test/profile/Linux/coverage-exception.cpp b/compiler-rt/test/profile/Linux/coverage-exception.cpp
new file mode 100644
index 0000000000000..c12303363fbb6
--- /dev/null
+++ b/compiler-rt/test/profile/Linux/coverage-exception.cpp
@@ -0,0 +1,142 @@
+// REQUIRES: lld-available
+// XFAIL: powerpc64-target-arch
+
+// RUN: %clangxx_profgen -std=c++17 -fuse-ld=lld -fcoverage-mapping -o %t %s
+// RUN: env LLVM_PROFILE_FILE=%t.profraw %run %t
+// RUN: llvm-profdata merge -o %t.profdata %t.profraw
+// RUN: llvm-cov show %t -instr-profile=%t.profdata 2>&1 | FileCheck %s
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define TRY_AND_CATCH_ALL(x) \
+ try { \
+ (x); \
+ } catch (...) { \
+ }
+
+#define TRY_MAYBE_CRASH(x) \
+ try { \
+ if ((x)) { \
+ printf("no crash\n"); \
+ } else { \
+ abort(); \
+ } \
+ } catch (...) { \
+ }
+
+#define TRY_AND_CATCH_CRASHES(x) \
+ try { \
+ (x); \
+ } catch (...) { \
+ abort(); \
+ }
+
+// clang-format off
+static
+int test_no_exception() { // CHECK: [[@LINE]]| 1|int test_no_exception()
+ int i = 0; // CHECK: [[@LINE]]| 1| int i
+ try { // CHECK: [[@LINE]]| 1| try {
+ i = 1; // CHECK: [[@LINE]]| 1| i =
+ } catch (...) { // CHECK: [[@LINE]]| 1| } catch (
+ abort(); // CHECK: [[@LINE]]| 0| abort();
+ } // CHECK: [[@LINE]]| 0| }
+ printf("%s: %u\n", __func__, i); // CHECK: [[@LINE]]| 1| printf(
+ return 0; // CHECK: [[@LINE]]| 1| return
+} // CHECK: [[@LINE]]| 1|}
+
+static
+int test_no_exception_macro() { // CHECK: [[@LINE]]| 1|int test_no_exception_macro()
+ int i = 0; // CHECK: [[@LINE]]| 1| int i
+ TRY_AND_CATCH_ALL(i = 1); // CHECK: [[@LINE]]| 1| TRY_AND_CATCH_ALL(
+ printf("%s: %u\n", __func__, i); // CHECK: [[@LINE]]| 1| printf(
+ return 0; // CHECK: [[@LINE]]| 1| return
+} // CHECK: [[@LINE]]| 1|}
+
+static
+int test_exception() { // CHECK: [[@LINE]]| 1|int test_exception()
+ try { // CHECK: [[@LINE]]| 1| try {
+ throw 1; // CHECK: [[@LINE]]| 1| throw
+ } catch (...) { // CHECK: [[@LINE]]| 1| } catch (
+ printf("%s\n", __func__); // CHECK: [[@LINE]]| 1| printf(
+ } // CHECK: [[@LINE]]| 1| }
+ return 0; // CHECK: [[@LINE]]| 1| return
+} // CHECK: [[@LINE]]| 1|}
+
+static
+int test_exception_macro() { // CHECK: [[@LINE]]| 1|int test_exception_macro()
+ TRY_AND_CATCH_ALL(throw 1); // CHECK: [[@LINE]]| 1| TRY_AND_CATCH_ALL(
+ printf("%s\n", __func__); // CHECK: [[@LINE]]| 1| printf(
+ return 0; // CHECK: [[@LINE]]| 1| return
+} // CHECK: [[@LINE]]| 1|}
+
+static
+int test_exception_macro_nested() { // CHECK: [[@LINE]]| 1|int test_exception_macro_nested()
+ try { // CHECK: [[@LINE]]| 1| try {
+ TRY_AND_CATCH_ALL(throw 1); // CHECK: [[@LINE]]| 1| TRY_AND_CATCH_ALL(
+ } catch (...) { // CHECK: [[@LINE]]| 1| } catch (
+ abort(); // CHECK: [[@LINE]]| 0| abort();
+ } // CHECK: [[@LINE]]| 0| }
+ printf("%s\n", __func__); // CHECK: [[@LINE]]| 1| printf(
+ return 0; // CHECK: [[@LINE]]| 1| return
+} // CHECK: [[@LINE]]| 1|}
+
+static
+int test_exception_try_crash() { // CHECK: [[@LINE]]| 1|int test_exception_try_crash()
+ int i = 1; // CHECK: [[@LINE]]| 1| int i
+ TRY_MAYBE_CRASH(i); // CHECK: [[@LINE]]| 1| TRY_MAYBE_CRASH(
+ printf("%s\n", __func__); // CHECK: [[@LINE]]| 1| printf(
+ return 0; // CHECK: [[@LINE]]| 1| return
+} // CHECK: [[@LINE]]| 1|}
+
+static
+int test_exception_crash() { // CHECK: [[@LINE]]| 1|int test_exception_crash()
+ int i = 0; // CHECK: [[@LINE]]| 1| int i
+ TRY_AND_CATCH_CRASHES(i = 1); // CHECK: [[@LINE]]| 1| TRY_AND_CATCH_CRASHES(
+ printf("%s\n", __func__); // CHECK: [[@LINE]]| 1| printf(
+ return 0; // CHECK: [[@LINE]]| 1| return
+} // CHECK: [[@LINE]]| 1|}
+
+static
+int test_conditional(int i) { // CHECK: [[@LINE]]| 1|int test_conditional(int i)
+ try { // CHECK: [[@LINE]]| 1| try {
+ if (i % 2 == 0) { // CHECK: [[@LINE]]| 1| if (
+ printf("%s\n", __func__); // CHECK: [[@LINE]]| 1| printf(
+ } else { // CHECK: [[@LINE]]| 1| } else {
+ abort(); // CHECK: [[@LINE]]| 0| abort();
+ } // CHECK: [[@LINE]]| 0| }
+ } catch (...) { // CHECK: [[@LINE]]| 1| } catch (
+ abort(); // CHECK: [[@LINE]]| 0| abort();
+ } // CHECK: [[@LINE]]| 0| }
+ return 0; // CHECK: [[@LINE]]| 1| return
+}
+
+static
+int test_multiple_catch() { // CHECK: [[@LINE]]| 1|int test_multiple_catch()
+ try { // CHECK: [[@LINE]]| 1| try {
+ throw 1; // CHECK: [[@LINE]]| 1| throw
+ } catch (double) { // CHECK: [[@LINE]]| 1| } catch (double)
+ abort(); // CHECK: [[@LINE]]| 0| abort();
+ } catch (int) { // CHECK: [[@LINE]]| 1| } catch (int)
+ printf("int\n"); // CHECK: [[@LINE]]| 1| printf(
+ } catch (float) { // CHECK: [[@LINE]]| 1| } catch (float)
+ abort(); // CHECK: [[@LINE]]| 0| abort();
+ } catch (...) { // CHECK: [[@LINE]]| 0| } catch (
+ abort(); // CHECK: [[@LINE]]| 0| abort();
+ } // CHECK: [[@LINE]]| 0| }
+ return 0; // CHECK: [[@LINE]]| 1| return
+} // CHECK: [[@LINE]]| 1|}
+
+int main() { // CHECK: [[@LINE]]| 1|int main()
+ test_no_exception(); // CHECK: [[@LINE]]| 1| test_no_exception(
+ test_no_exception_macro(); // CHECK: [[@LINE]]| 1| test_no_exception_macro(
+ test_exception(); // CHECK: [[@LINE]]| 1| test_exception(
+ test_exception_macro(); // CHECK: [[@LINE]]| 1| test_exception_macro(
+ test_exception_macro_nested(); // CHECK: [[@LINE]]| 1| test_exception_macro_nested(
+ test_exception_try_crash(); // CHECK: [[@LINE]]| 1| test_exception_try_crash(
+ test_exception_crash(); // CHECK: [[@LINE]]| 1| test_exception_crash(
+ test_conditional(2); // CHECK: [[@LINE]]| 1| test_conditional(
+ test_multiple_catch(); // CHECK: [[@LINE]]| 1| test_multiple_catch(
+ return 0; // CHECK: [[@LINE]]| 1| return
+} // CHECK: [[@LINE]]| 1|}
+// clang-format on
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