cor3ntin created this revision.
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Clang crashes when encountering an `if consteval` statement.
This is the minimum fix not to crash.
The fix is consistent with the current behavior of if constexpr,
which does generate coverage data for the discarded branches.
This is of course not correct and a better solution is
needed for both if constexpr and if consteval.
See https://github.com/llvm/llvm-project/issues/54419.
Fixes #57377
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D132723
Files:
clang/lib/CodeGen/CoverageMappingGen.cpp
clang/test/CoverageMapping/if.cpp
Index: clang/test/CoverageMapping/if.cpp
===================================================================
--- clang/test/CoverageMapping/if.cpp
+++ clang/test/CoverageMapping/if.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -std=c++1z -triple %itanium_abi_triple -main-file-name if.cpp %s | FileCheck %s
+// RUN: %clang_cc1 -mllvm -emptyline-comment-coverage=false -fprofile-instrument=clang -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -std=c++2b -triple %itanium_abi_triple -main-file-name if.cpp %s | FileCheck %s
int nop() { return 0; }
@@ -13,6 +13,22 @@
++j; // CHECK-NEXT: Branch,File 0, [[@LINE-1]]:7 -> [[@LINE-1]]:8 = #1, (#0 - #1)
} // 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;
+ }
+}
+
// CHECK-LABEL: main:
int main() { // CHECK: File 0, [[@LINE]]:12 -> {{[0-9]+}}:2 = #0
int i = 0;
@@ -50,6 +66,10 @@
// 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);
+
return 0;
}
Index: clang/lib/CodeGen/CoverageMappingGen.cpp
===================================================================
--- clang/lib/CodeGen/CoverageMappingGen.cpp
+++ clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -1372,24 +1372,29 @@
void VisitIfStmt(const IfStmt *S) {
extendRegion(S);
+
if (S->getInit())
Visit(S->getInit());
// Extend into the condition before we propagate through it below - this is
// needed to handle macros that generate the "if" but not the condition.
- extendRegion(S->getCond());
+ if (!S->isConsteval()) {
+ extendRegion(S->getCond());
+ }
Counter ParentCount = getRegion().getCounter();
Counter ThenCount = getRegionCounter(S);
- // Emitting a counter for the condition makes it easier to interpret the
- // counter for the body when looking at the coverage.
- propagateCounts(ParentCount, S->getCond());
+ if (!S->isConsteval()) {
+ // Emitting a counter for the condition makes it easier to interpret the
+ // counter for the body when looking at the coverage.
+ propagateCounts(ParentCount, S->getCond());
- // The 'then' count applies to the area immediately after the condition.
- auto Gap = findGapAreaBetween(S->getRParenLoc(), getStart(S->getThen()));
- if (Gap)
- fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), ThenCount);
+ // The 'then' count applies to the area immediately after the condition.
+ auto Gap = findGapAreaBetween(S->getRParenLoc(), getStart(S->getThen()));
+ if (Gap)
+ fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), ThenCount);
+ }
extendRegion(S->getThen());
Counter OutCount = propagateCounts(ThenCount, S->getThen());
@@ -1398,9 +1403,8 @@
if (const Stmt *Else = S->getElse()) {
bool ThenHasTerminateStmt = HasTerminateStmt;
HasTerminateStmt = false;
-
// The 'else' count applies to the area immediately after the 'then'.
- Gap = findGapAreaBetween(getEnd(S->getThen()), getStart(Else));
+ auto Gap = findGapAreaBetween(getEnd(S->getThen()), getStart(Else));
if (Gap)
fillGapAreaWithCount(Gap->getBegin(), Gap->getEnd(), ElseCount);
extendRegion(Else);
@@ -1416,9 +1420,11 @@
GapRegionCounter = OutCount;
}
- // Create Branch Region around condition.
- createBranchRegion(S->getCond(), ThenCount,
- subtractCounters(ParentCount, ThenCount));
+ if (!S->isConsteval()) {
+ // Create Branch Region around condition.
+ createBranchRegion(S->getCond(), ThenCount,
+ subtractCounters(ParentCount, ThenCount));
+ }
}
void VisitCXXTryStmt(const CXXTryStmt *S) {
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