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Detect tail call when scanning functions.

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Unknown W. Brackets 2013-12-01 21:56:28 -08:00
parent 1bccfa4141
commit 505f509503
1 changed files with 34 additions and 2 deletions
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36
Core/MIPS/MIPSAnalyst.cpp
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@ -240,6 +240,12 @@ namespace MIPSAnalyst {
static u32 ScanAheadForJumpback(u32 fromAddr, u32 knownStart, u32 knownEnd) {
static const u32 MAX_AHEAD_SCAN = 0x1000;
// Maybe a bit high... just to make sure we don't get confused by recursive tail recursion.
static const u32 MAX_FUNC_SIZE = 0x20000;
if (fromAddr > knownEnd + MAX_FUNC_SIZE) {
return INVALIDTARGET;
}
// Code might jump halfway up to before fromAddr, but after knownEnd.
// In that area, there could be another jump up to the valid range.
@ -320,6 +326,31 @@ namespace MIPSAnalyst {
if (target > furthestBranch) {
furthestBranch = target;
}
} else if ((op & 0xFC000000) == 0x08000000) {
u32 sureTarget = GetJumpTarget(addr);
// Check for a tail call. Might not even have a jr ra.
if (sureTarget != INVALIDTARGET && sureTarget < currentFunction.start) {
if (furthestBranch > addr) {
looking = true;
addr += 4;
} else {
end = true;
}
} else if (sureTarget != INVALIDTARGET && sureTarget > addr && sureTarget > furthestBranch) {
// A jump later. Probably tail, but let's check if it jumps back.
u32 knownEnd = furthestBranch == 0 ? addr : furthestBranch;
u32 jumpback = ScanAheadForJumpback(sureTarget, currentFunction.start, knownEnd);
if (jumpback != INVALIDTARGET && jumpback > addr && jumpback > knownEnd) {
furthestBranch = jumpback;
} else {
if (furthestBranch > addr) {
looking = true;
addr += 4;
} else {
end = true;
}
}
}
}
if (op == MIPS_MAKE_JR_RA()) {
// If a branch goes to the jr ra, it's still ending here.
@ -344,8 +375,9 @@ namespace MIPSAnalyst {
} else if (sureTarget != INVALIDTARGET) {
// Okay, we have a downward jump. Might be an else or a tail call...
// If there's a jump back upward in spitting distance of it, it's an else.
u32 jumpback = ScanAheadForJumpback(sureTarget, currentFunction.start, furthestBranch);
if (jumpback != INVALIDTARGET && jumpback > addr && jumpback > furthestBranch) {
u32 knownEnd = furthestBranch == 0 ? addr : furthestBranch;
u32 jumpback = ScanAheadForJumpback(sureTarget, currentFunction.start, knownEnd);
if (jumpback != INVALIDTARGET && jumpback > addr && jumpback > knownEnd) {
furthestBranch = jumpback;
}
}