luke/verilator
1
0
Fork 0
mirror of https://github.com/verilator/verilator.git synced 2026-10-06 01:54:01 +02:00
Code Issues Packages Projects Releases Wiki Activity

Fix deep defines causing flex scanner overflows.

Browse Source
This commit is contained in:
Wilson Snyder
2009-09-17 22:23:18 -04:00
parent d37cc5a160
commit abc738b6f1
4 changed files with 77 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/V3PreProc.cpp
+36 -13
View File
@@ -160,6 +160,7 @@ private:
bool commentTokenMatch(string& cmdr, const char* strg);
string trimWhitespace(const string& strg);
void unputString(const string& strg);
void parsingOn() {
m_off--;
@@ -386,6 +387,18 @@ const char* V3PreProcImp::tokenName(int tok) {
}
}
void V3PreProcImp::unputString(const string& strg) {
// We used to just m_lexp->unputString(strg.c_str());
// However this can lead to "flex scanner push-back overflow"
// so instead we scan from a temporary buffer, then on EOF return.
// This is also faster than the old scheme, amazingly.
if (m_lexp->m_bufferStack.empty() || m_lexp->m_bufferStack.top()!=m_lexp->currentBuffer()) {
fileline()->v3fatalSrc("bufferStack missing current buffer; will return incorrectly");
// Hard to debug lost text as won't know till much later
}
m_lexp->scanBytes(strg);
}
string V3PreProcImp::trimWhitespace(const string& strg) {
string out = strg;
while (out.length()>0 && isspace(out[0])) {
@@ -535,7 +548,6 @@ void V3PreProcImp::openFile(FileLine* fl, const string& filename) {
addLineComment(1); // Enter
yy_flex_debug = (debug()>4)?1:0;
yy_switch_to_buffer(m_lexp->m_yyState);
}
void V3PreProcImp::insertUnreadbackAtBol(const string& text) {
@@ -560,16 +572,27 @@ void V3PreProcImp::addLineComment(int enter_exit_level) {
}
void V3PreProcImp::eof() {
// Remove current lexer
UINFO(4,fileline()<<"EOF!\n");
addLineComment(2); // Exit
delete m_lexp; m_lexp=NULL;
// Perhaps there's a parent file including us?
if (!m_includeStack.empty()) {
// Back to parent.
m_lexp = m_includeStack.top(); m_includeStack.pop();
addLineComment(0);
yy_switch_to_buffer(m_lexp->m_yyState);
// Perhaps we're completing unputString
if (m_lexp->m_bufferStack.size()>1) {
UINFO(4,fileline()<<"EOS\n");
// Switch to file or next unputString, but not a eof so don't delete lexer
yy_delete_buffer(m_lexp->currentBuffer());
m_lexp->m_bufferStack.pop(); // Must work as size>1
yy_switch_to_buffer(m_lexp->m_bufferStack.top());
} else {
// Remove current lexer
UINFO(4,fileline()<<"EOF!\n");
addLineComment(2); // Exit
// Destructor will call yy_delete_buffer
delete m_lexp; m_lexp=NULL;
// Perhaps there's a parent file including us?
if (!m_includeStack.empty()) {
// Back to parent.
m_lexp = m_includeStack.top(); m_includeStack.pop();
addLineComment(0);
if (m_lexp->m_bufferStack.empty()) fileline()->v3fatalSrc("No include buffer to return to");
yy_switch_to_buffer(m_lexp->m_bufferStack.top()); // newest buffer in older lexer
}
}
}
@@ -808,7 +831,7 @@ int V3PreProcImp::getToken() {
// Similar code in non-parenthesized define (Search for END_OF_DEFARG)
m_defRefs.pop();
if (m_defRefs.empty()) {
m_lexp->unputString(out.c_str());
unputString(out.c_str());
m_state = ps_TOP;
m_lexp->m_parenLevel = 0;
}
@@ -941,7 +964,7 @@ int V3PreProcImp::getToken() {
// Similar code in parenthesized define (Search for END_OF_DEFARG)
if (m_defRefs.empty()) {
// Just output the substitution
m_lexp->unputString(out.c_str());
unputString(out.c_str());
} else {
// Inside another define. Can't subst now, or
// `define a x,y