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cxxrtl: use CXXRTL_ASSERT for RTL contract violations instead of assert. 

RTL contract violations and C++ contract violations are different:
the former depend on the netlist and will never violate memory safety
whereas the latter may. When loading a CXXRTL simulation into another
process, RTL contract violations should generally not crash it, while
C++ contract violations should.
This commit is contained in:
whitequark 2020-12-02 19:41:00 +00:00
parent 7b0cfd5c36
commit aa0a15a42c
2 changed files with 16 additions and 2 deletions
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14
backends/cxxrtl/cxxrtl.h
View File

@ -53,6 +53,20 @@
#define CXXRTL_ALWAYS_INLINE inline
#endif
// CXXRTL uses assert() to check for C++ contract violations (which may result in e.g. undefined behavior
// of the simulation code itself), and CXXRTL_ASSERT to check for RTL contract violations (which may at
// most result in undefined simulation results).
//
// Though by default, CXXRTL_ASSERT() expands to assert(), it may be overridden e.g. when integrating
// the simulation into another process that should survive violating RTL contracts.
#ifndef CXXRTL_ASSERT
#ifndef CXXRTL_NDEBUG
#define CXXRTL_ASSERT(x) assert(x)
#else
#define CXXRTL_ASSERT(x)
#endif
#endif
namespace cxxrtl {
// All arbitrary-width values in CXXRTL are backed by arrays of unsigned integers called chunks. The chunk size

4
backends/cxxrtl/cxxrtl_backend.cc
View File

@ -1154,7 +1154,7 @@ struct CxxrtlWorker {
// larger program) will never crash the code that calls into it.
//
// If assertions are disabled, out of bounds reads are defined to return zero.
f << indent << "assert(" << valid_index_temp << ".valid && \"out of bounds read\");\n";
f << indent << "CXXRTL_ASSERT(" << valid_index_temp << ".valid && \"out of bounds read\");\n";
f << indent << "if(" << valid_index_temp << ".valid) {\n";
inc_indent();
if (writable_memories[memory]) {
@ -1211,7 +1211,7 @@ struct CxxrtlWorker {
// See above for rationale of having both the assert and the condition.
//
// If assertions are disabled, out of bounds writes are defined to do nothing.
f << indent << "assert(" << valid_index_temp << ".valid && \"out of bounds write\");\n";
f << indent << "CXXRTL_ASSERT(" << valid_index_temp << ".valid && \"out of bounds write\");\n";
f << indent << "if (" << valid_index_temp << ".valid) {\n";
inc_indent();
f << indent << mangle(memory) << ".update(" << valid_index_temp << ".index, ";