HELP: basic-block
{ $class-description
"Factors representation of a basic block in the Call Flow Graph (CFG). A basic block is a sequence of instructions that always are executed sequentially and doesn't contain any internal branching. It has the following slots:"
- { $table
+ { $slots
{
- { $slot "number" }
+ "number"
{ "The blocks sequence number. Generated by calling " { $link number-blocks } "." }
}
{
- { $slot "successors" }
+ "successors"
{ "A " { $link vector } " of basic blocks that may be executed directly after this block. Most blocks only have one successor but a block that checks where an if-condition should branch to would have two for example." }
}
{
- { $slot "predecessors" }
+ "predecessors"
{ "The opposite of successors -- a " { $link vector } " of basic blocks from which the execution may have arrived into this block." }
}
{
- { $slot "instructions" }
+ "instructions"
{ "A " { $link vector } " of " { $link insn } " tuples which form the instructions of the basic block." }
}
{
- { $slot "kill-block?" }
+ "kill-block?"
{ "The first and the last block in a cfg and all blocks containing " { $link ##call } " instructions are kill blocks. Kill blocks can't be optimized so they are omitted from certain optimization steps." }
}
{
- { $slot "height" }
+ "height"
"Block's height as a " { $link height-state } ". What the heights of the block was at entry and how much they were increased in the block."
}
{
- { $slot "replaces" }
+ "replaces"
{ "Used by " { $vocab-link "compiler.cfg.stacks.local" } " for local stack analysis." }
}
{
- { $slot "peeks" }
+ "peeks"
{ "Used by " { $vocab-link "compiler.cfg.stacks.local" } " for local stack analysis." }
}
{
- { $slot "kills" }
+ "kills"
{ "Used by " { $vocab-link "compiler.cfg.stacks.local" } " for local stack analysis." }
}
}
HELP: cfg
{ $class-description
"Call flow graph. It has the following slots:"
- { $table
- { { $slot "entry" } { "Root " { $link basic-block } " of the graph." } }
- { { $slot "word" } { "The " { $link word } " the cfg is produced from." } }
- { { $slot "post-order" } { "The blocks of the cfg in a post order traversal " { $link sequence } "." } }
- { { $slot "stack-frame" } { { $link stack-frame } " of the cfg." } }
- { { $slot "frame-pointer?" } { "Whether the cfg needs a frame pointer. Only cfgs generated for " { $link #alien-callback } " nodes does need it. If the slot is " { $link t } ", then the frame pointer register (" { $link RBP } " on x86.64 archs) will not be clobbered by register allocation. See " { $vocab-link "compiler.cfg.linear-scan" } " for details." } }
+ { $slots
+ { "entry" { "Root " { $link basic-block } " of the graph." } }
+ { "word" { "The " { $link word } " the cfg is produced from." } }
+ { "post-order" { "The blocks of the cfg in a post order traversal " { $link sequence } "." } }
+ { "stack-frame" { { $link stack-frame } " of the cfg." } }
+ { "frame-pointer?" { "Whether the cfg needs a frame pointer. Only cfgs generated for " { $link #alien-callback } " nodes does need it. If the slot is " { $link t } ", then the frame pointer register (" { $link RBP } " on x86.64 archs) will not be clobbered by register allocation. See " { $vocab-link "compiler.cfg.linear-scan" } " for details." } }
}
}
{ $see-also <cfg> post-order } ;