[clang] [clang][CoverageMapping] do not emit gap when either end is an `ImplicitValueInitExpr` (PR #89564)

[Wentao Zhang via cfe-commits]

https://github.com/whentojump updated https://github.com/llvm/llvm-project/pull/89564

>From abbdb318d62bb2e5ab6f07e7d0fe11f4a06b5a11 Mon Sep 17 00:00:00 2001
From: Wentao Zhang <zhangwt1997 at gmail.com>
Date: Sun, 21 Apr 2024 21:27:01 -0500
Subject: [PATCH 1/2] [clang][CoverageMapping] do not emit gap when either end
 is an ImplicitValueInitExpr

---
 clang/lib/CodeGen/CoverageMappingGen.cpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp
index 64c39c5de351c7..dd8c0577d758ca 100644
--- a/clang/lib/CodeGen/CoverageMappingGen.cpp
+++ b/clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -1368,9 +1368,12 @@ struct CounterCoverageMappingBuilder
     for (const Stmt *Child : S->children())
       if (Child) {
         // If last statement contains terminate statements, add a gap area
-        // between the two statements. Skipping attributed statements, because
-        // they don't have valid start location.
-        if (LastStmt && HasTerminateStmt && !isa<AttributedStmt>(Child)) {
+        // between the two statements. Skipping attributed statements and
+        // implicit initializations, because they don't have valid source
+        // location.
+        if (LastStmt && HasTerminateStmt && !isa<AttributedStmt>(Child) &&
+            !isa<ImplicitValueInitExpr>(Child) &&
+            !isa<ImplicitValueInitExpr>(LastStmt)) {
           auto Gap = findGapAreaBetween(getEnd(LastStmt), getStart(Child));
           if (Gap)
             fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(),

>From cc42595ea34f4f4b5b9dda968f323ec95ba712e9 Mon Sep 17 00:00:00 2001
From: Wentao Zhang <zhangwt1997 at gmail.com>
Date: Mon, 22 Apr 2024 11:17:49 -0500
Subject: [PATCH 2/2] add tests

---
 .../CoverageMapping/statement-expression.c    | 36 +++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 clang/test/CoverageMapping/statement-expression.c

diff --git a/clang/test/CoverageMapping/statement-expression.c b/clang/test/CoverageMapping/statement-expression.c
new file mode 100644
index 00000000000000..6006e3646ee943
--- /dev/null
+++ b/clang/test/CoverageMapping/statement-expression.c
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -main-file-name statement-expression.c %s
+
+// No crash for the following examples, where GNU Statement Expression extension
+// could contain region terminators (break, goto etc) before implicit
+// initializers in a struct or an array.
+// See https://github.com/llvm/llvm-project/pull/89564
+
+struct Foo {
+  int field1;
+  int field2;
+};
+
+void test1(void) {
+  struct Foo foo = {
+    .field1 = ({
+      switch (0) {
+      case 0:
+        break; // A region terminator
+      }
+      0;
+    }),
+    // ImplicitValueInitExpr introduced here for .field2
+  };
+}
+
+void test2(void) {
+  int arr[3] = {
+    [0] = ({
+        goto L0; // A region terminator
+L0:
+      0;
+    }),
+    // ImplicitValueInitExpr introduced here for subscript [1]
+    [2] = 0,
+  };
+}