US 8,266,597 B2Granted

Dynamically patching computer code using breakpoints

AssigneeInternational Business Machines Corporation

InventorsPrasanna S. Panchamukhi, Balbir Singh

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Abstract

A first section of executable computer code of a computer program is dynamically patched by performing the following. A breakpoint is inserted at the first section of executable computer code. During execution of the computer program, an instruction counter is incremented on an instruction-by-instruction basis through the computer program. The instruction counter indicates a current instruction of the computer program being executed. The breakpoint where the instruction counter points to the first section of executable computer code is encountered, which results in a breakpoint handler being called. The breakpoint handler changes the instruction pointer to instead point to a second section of executable computer code. The second section of executable computer code is a patched version of the first section of executable computer code. Upon the breakpoint handler returning, the second section of executable computer code is executed in lieu of the first section of executable computer code.

Claims19

Dependent claims

A method for dynamically patching a first section of executable computer code of a computer program, comprising:

inserting a breakpoint at the first section of executable computer code of the computer program;
during execution of the computer program by a processor of a computing device,
an instruction counter incrementing on an instruction-by-instruction basis through the computer program, the instruction counter indicating a current instruction of the computer program being executed, the instruction counter incremented by the processor;
encountering the breakpoint where the instruction pointer points to the first section of executable computer code, resulting in a breakpoint handler being called, the breakpoint encountered by the processor;
the breakpoint handler changing the instruction pointer to instead point to a second section of executable computer code, the second section of executable computer code being a patched version of the first section of executable computer code, the breakpoint handler executed by the processor;
and,
upon the breakpoint handler returning, the second section of executable computer code being executed by the processor in lieu of the first section of executable computer code,
wherein the first section of executable computer code of the computer program is dynamically patched without having to know at time of compiling a location at which the breakpoint is to be added at the first section of executable computer code.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/139,576Filed 16 Jun 2008
Published: US 2009/0313611 A117 Dec 2009
Granted: 11 Sep 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G06F 11/36
Error detection; Error correction; Monitoring: prevention of errors by analysis, debugging or testing of software
G06F 9/32
Arrangements for executing machine instructions, e.g. instruction decode: address formation of the next instruction, e.g. by incrementing the…
G06F 9/328
For non-sequential address: for runtime instruction patching
G06F
Computing and data processing