[PATCH] D79760: [WinEH64] Fix a crush issue when c++ exception nested in a particular form.

[Pengfei Wang via Phabricator via llvm-commits]

pengfei added a comment.

In D79760#2033315 <https://reviews.llvm.org/D79760#2033315>, @tentzen wrote:

> I meant did you debug into the crash of your test case in https://bugs.llvm.org/show_bug.cgi?id=42266 ?


Yes. I dumped the RSP/ESP value using below code

  #include <stdio.h>
  
  #if _WIN64
  unsigned long long rbp, rsp;
  #define DUMP_REGS(STR, ...) \
  	asm("mov %%rbp, %0\nmov %%rsp, %1" : "=m"(rbp), "=m"(rsp)); \
  	printf(STR "\tRSP = %llx\tRBP = %llx\n", __VA_ARGS__, rsp, rbp);
  #else
  unsigned long ebp, esp;
  #define DUMP_REGS(STR, ...) \
  	asm("mov %%ebp, %0\nmov %%esp, %1" : "=m"(ebp), "=m"(esp)); \
  	printf(STR "\tESP = %llx\tEBP = %llx\n", __VA_ARGS__, esp, ebp);
  #endif
  
  void foo()
  {
  	DUMP_REGS("**FOO**")
  	try {
  		throw 1;
  	}
  	catch (int x) {
  		DUMP_REGS("Catch %d", x)
  		try {
  			try {
  				throw 2;
  			}
  			catch (int x) {
  				DUMP_REGS("Catch %d", x)
  				throw 3;
  			}
  		}
  		catch (int x) {
  			DUMP_REGS("Catch %d", x)
  		}
  		DUMP_REGS("Catch %d", x)
  	}
  	DUMP_REGS("FOO ret")
  };
  
  int main()
  {
  	foo();
  }

The output on 64 bits is something like this

  **FOO** RSP = bc583bf880        RBP = bc583bf900
  Catch 1 RSP = bc583bd640        RBP = bc583bf900
  Catch 2 RSP = bc583bb400        RBP = bc583bf900
  Catch 3 RSP = bc583b91c0        RBP = bc583bf900
  Catch 1 RSP = bc583bb400        RBP = bc583bf900
  FOO ret RSP = bc583bd640        RBP = bc583bf900

Which made me guess it caused by the runtime that not set the proper stack value. Then I compared each structure LLVM generated with MSVC and found the order of try map table is the key.


Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D79760