From b572f6421296e7688973014d253e46c54fd64ba3 Mon Sep 17 00:00:00 2001 From: Vedant Kumar Date: Thu, 26 Jul 2018 20:56:53 +0000 Subject: [DebugInfo] LowerDbgDeclare: Add derefs when handling CallInst users LowerDbgDeclare inserts a dbg.value before each use of an address described by a dbg.declare. When inserting a dbg.value before a CallInst use, however, it fails to append DW_OP_deref to the DIExpression. The DW_OP_deref is needed to reflect the fact that a dbg.value describes a source variable directly (as opposed to a dbg.declare, which relies on pointer indirection). This patch adds in the DW_OP_deref where needed. This results in the correct values being shown during a debug session for a program compiled with ASan and optimizations (see https://reviews.llvm.org/D49520). Note that ConvertDebugDeclareToDebugValue is already correct -- no changes there were needed. One complication is that SelectionDAG is unable to distinguish between direct and indirect frame-index (FRAMEIX) SDDbgValues. This patch also fixes this long-standing issue in order to not regress integration tests relying on the incorrect assumption that all frame-index SDDbgValues are indirect. This is a necessary fix: the newly-added DW_OP_derefs cannot be lowered properly otherwise. Basically the fix prevents a direct SDDbgValue with DIExpression(DW_OP_deref) from being dereferenced twice by a debugger. There were a handful of tests relying on this incorrect "FRAMEIX => indirect" assumption which actually had incorrect DW_AT_locations: these are all fixed up in this patch. Testing: - check-llvm, and an end-to-end test using lldb to debug an optimized program. - Existing unit tests for DIExpression::appendToStack fully cover the new DIExpression::append utility. - check-debuginfo (the debug info integration tests) Differential Revision: https://reviews.llvm.org/D49454 llvm-svn: 338069 --- debuginfo-tests/asan-deque.cpp | 46 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 debuginfo-tests/asan-deque.cpp (limited to 'debuginfo-tests') diff --git a/debuginfo-tests/asan-deque.cpp b/debuginfo-tests/asan-deque.cpp new file mode 100644 index 00000000000..19183d6cc15 --- /dev/null +++ b/debuginfo-tests/asan-deque.cpp @@ -0,0 +1,46 @@ +// RUN: %clangxx -arch x86_64 %target_itanium_abi_host_triple -O1 -g %s -o %t.out -fsanitize=address +// RUN: %test_debuginfo %s %t.out +// REQUIRES: not_asan +// Zorg configures the ASAN stage2 bots to not build the asan +// compiler-rt. Only run this test on non-asanified configurations. + +#include + +struct A { + int a; + A(int a) : a(a) {} +}; + +using log_t = std::deque; + +static void __attribute__((noinline, optnone)) escape(log_t &log) { + static volatile log_t *sink; + sink = &log; +} + +int main() { + log_t log; + log.emplace_back(1234); + log.emplace_back(56789); + escape(log); + // DEBUGGER: break 25 + while (!log.empty()) { + auto record = log.front(); + log.pop_front(); + escape(log); + // DEBUGGER: break 30 + } +} + +// DEBUGGER: r + +// (at line 25) +// DEBUGGER: p log +// CHECK: 1234 +// CHECK: 56789 + +// DEBUGGER: c + +// (at line 30) +// DEBUGGER: p log +// CHECK: 56789 -- cgit v1.2.1